Campbell Scientific CR5000 User Manual

Download

CR5000 Measurement and

Control System

Revision: 11/06

Campbell Scientific, Inc.

Warranty and Assistance

The CR5000 MEASUREMENT AND CONTROL SYSTEM is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for thirty-six (36) months from date of shipment unless specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products. The customer shall assume all costs of removing, reinstalling, and shipping defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will return such products by surface carrier prepaid. This warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products which have been subjected to modification, misuse, neglect, accidents of nature, or shipping damage. This warranty is in lieu of all other warranties, expressed or implied, including warranties of merchantability or fitness for a particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special, indirect, incidental, or consequential damages.

Products may not be returned without prior authorization. The following contact information is for US and International customers residing in countries served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs for customers within their territories. Please visit www.campbellsci.com to determine which Campbell Scientific company serves your country. To obtain a Returned Materials Authorization (RMA), contact CAMPBELL SCIENTIFIC, INC., phone (435) 753-2342. After an applications engineer determines the nature of the problem, an RMA number will be issued. Please write this number clearly on the outside of the shipping container. CAMPBELL SCIENTIFIC's shipping address is:

CAMPBELL SCIENTIFIC, INC.

RMA#_____ 815 West 1800 North Logan, Utah 84321-1784

CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

CR5000 MEASUREMENT AND CONTROL SYSTEM

PDF viewers note: These page numbers refer to the printed version of this document. Use the Adobe Acrobat® bookmarks tab for links to specific sections.

PAGE

OV1. PHYSICAL DESCRIPTION

OV1.1 Measurement Inputs...........................................................................................................OV-1

OV1.2 Communication and Data Storage...................................................................................... OV-4

OV1.3 Power Supply and AC Adapter...........................................................................................OV-5

OV2. MEMORY AND PROGRAMMING CONCEPTS

OV2.1 Memory...............................................................................................................................OV-5

OV2.2 Measurements, Processing, Data Storage.........................................................................OV-5

OV2.3 Data Tables......................................................................................................................... OV-6

OV3. PC9000 APPLICATION SOFTWARE

OV3.1 Hardware and Software Requirements ..............................................................................OV-6

OV3.2 PC9000 Installation.............................................................................................................OV-6

OV3.3 PC9000 Software Overview................................................................................................ OV-7

OV4. KEYBOARD DISPLAY

OV4.1 Data Display...................................................................................................................... OV-12

OV4.2 Run/Stop Program............................................................................................................OV-16

OV4.3 File Display........................................................................................................................OV-17

OV4.4 Configure Display.............................................................................................................. OV-19

OV5. SPECIFICATIONS..........................................................................................................OV-20

1. INSTALLATION AND MAINTENANCE

1.1 Protection from the Environment........................................................................................... 1-1

1.2 Power Requirements ............................................................................................................. 1-1

1.3 CR5000 Power Supplies........................................................................................................ 1-2

1.4 Solar Panels........................................................................................................................... 1-4

1.5 Direct Battery Connection to the CR5000 Wiring Panel........................................................ 1-4

1.6 Vehicle Power Supply Connections....................................................................................... 1-4

1.7 CR5000 Grounding................................................................................................................ 1-6

1.8 Powering Sensors and Peripherals ....................................................................................... 1-9

1.9 Controlling Power to Sensors and Peripherals.................................................................... 1-10

1.10 Maintenance ........................................................................................................................ 1-12

2. DATA STORAGE AND RETRIEVAL

2.1 Data Storage in CR5000........................................................................................................ 2-1

2.2 Internal Data Format.............................................................................................................. 2-2

2.3 Data Collection....................................................................................................................... 2-3

2.4 Data Format on Computer................................................................................................... 2-10

CR5000 TABLE OF CONTENTS

3. CR5000 MEASUREMENT DETAILS

3.1 Analog Voltage Measurement Sequence.............................................................................. 3-1

3.2 Single Ended and Differential Voltage Measurements.......................................................... 3-4

3.3 Signal Settling Time............................................................................................................... 3-5

3.4 Thermocouple Measurements............................................................................................... 3-7

3.5 Bridge Resistance Measurements.......................................................................................3-17

3.6 Measurements Requiring AC Excitation.............................................................................. 3-19

3.7 Pulse Count Measurements................................................................................................. 3-20

3.8 Self Calibration..................................................................................................................... 3-21

4. CRBASIC - NATIVE LANGUAGE PROGRAMMING

4.1 Format Introduction................................................................................................................4-1

4.2 Programming Sequence........................................................................................................4-2

4.3 Example Program .................................................................................................................. 4-4

4.4 Numerical Entries................................................................................................................... 4-7

4.5 Logical Expression Evaluation...............................................................................................4-7

4.6 Flags ......................................................................................................................................4-8

4.7 Parameter Types ................................................................................................................... 4-9

4.8 Program Access to Data Tables.......................................................................................... 4-10

5. PROGRAM DECLARATIONS ........................................................................................... 5-1

6. DATA TABLE DECLARATIONS AND OUTPUT PROCESSING INSTRUCTIONS

6.1 Data Table Declaration.......................................................................................................... 6-1

6.2 Trigger Modifiers.................................................................................................................... 6-2

6.3 Export Data Instructions......................................................................................................... 6-8

6.4 Output Processing Instructions............................................................................................ 6-11

7. MEASUREMENT INSTRUCTIONS

7.1 Voltage Measurements.......................................................................................................... 7-3

7.2 Thermocouple Measurements............................................................................................... 7-3

7.3 Half Bridges............................................................................................................................ 7-5

7.4 Full Bridges............................................................................................................................ 7-8

7.5 Current Excitation ................................................................................................................ 7-11

7.6 Excitation/Continuous Analog Output.................................................................................. 7-13

7.7 Self Measurements.............................................................................................................. 7-15

7.8 Digital I/O ............................................................................................................................. 7-19

7.9 Peripheral Devices...............................................................................................................7-29

8. PROCESSING AND MATH INSTRUCTIONS............................................................... 8-1

9. PROGRAM CONTROL INSTRUCTIONS....................................................................... 9-1

APPENDIX

A. CR5000 STATUS TABLE....................................................................................................A-1

INDEX ......................................................................................................................................... INDEX-1

CR5000 Overview

The CR5000 provides precision measurement capabilities in a rugged, battery-operated package. The system makes measurements at a rate of up to 5,000 samples/second with 16-bit resolution. The CR5000 includes CPU, keyboard display, power supply, and analog and digital inputs and outputs. The on-board, BASIC-like programming language includes data processing and analysis routines. PC9000 Software provides program generation and editing, data retrieval, and realtime monitoring.

19 20

17 18

15 16

13 14

11 12

910

DIFF

25 26

23 24

21 22

H L

DIFF

VX1

VX3

VX2

VX4

CONTROL I/O

POWER

Logan, Utah

CR5000 MICROLOGGER

27 28

CAO1

CAO2

IX1

IX2

>2.0V

<0.8V

33 34

31 32

29 30

H L

CONTRO

IX3

IX4

IXR

C1C2C3

SDI-12

12V

SDM-C1

SDM-C2

SDM-C3

12V

POWER OUT

A B C

D E F

PgUp

G H I

J K L

M N O

Graph/

char

P R S

T U V

W X Y

End

PgDn

- + ( * / )

< = >

Del

Ins

ESC

SN:

35 36

H L

L I/O

SW-12

CURSOR

ALPHA

SHIFT

Spc Cap

BKSPC

$ Q Z

ENTER

37 38

H L

POWER IN

11 - 16 VDC

CAUTION DC ONLY

12V

MADE IN USA

CS I/O

39 40

H L

RS-232

COMPUTER

(OPTICALLY ISOLATED)

GROUND

LUG

pc card

status

FIGURE OV1-1. CR5000 Measurement and Control System

OV1. Physical Description

Figure OV1-2 shows the CR5000 panel and the associated program instructions. Unless otherwise noted, they are measurement instructions (Section 7).

OV1.1 Measurement Inputs

OV1.1.1 Analog Inputs

There are 20 differential or 40 single-ended inputs for measuring voltages up to ±5 V. A thermistor installed in the wiring panel can be used to measure the reference temperature for thermocouple measurements, and a heavy copper grounding bar and connectors combine with the case design to reduce temperature gradients for accurate thermocouple measurements. Resolution on the most sensitive range is 0.67 µV

OV-1

CR5000 Overview

SWITCHED VOLTAGE EXCITATION (VX)

Excite BrFull BrFull6w BrHalf BrHalf3W BrHalf4W

VX1

23 24

VX2

VX3

DIFF

CONTINUOUS ANALOG OUTPUTS (CAO)

ExciteCAO

SWITCHED CURRENT EXCITATION (IX)

ExciteI Resistance

910

25 26

27 28

VX4

CAO1

CAO2

IX1

IX2

IX3

29 30

IX4

11 12

31 32

IXR

13 14

33 34

PULSE INPUTS

PulseCount PulseCountRese

15 16

17 18

35 36

37 38

CONTROL I/O

C1C2C3

CONTROL I/O

PortGet PortSet ReadIO TimerIO WriteIO

19 20

39 40

COMPUTER RS-232

CS I/O

(OPTICALLY ISOLATED)

ANALOG INPUTS

Voltage VoltDiff VoltSE Thermocouple TCDiff TCSE Bridge measurements (use VX) BrFull BrFull6W BrHalf BrHalf3W BrHalf4W Others Resistance PanelTemp PeriodAvg AM25T

SIGNAL GROUND ( FOR

Analog Pulse Excitation

CS I/O

DSP4 (Data Tables and Output)

GC5C6C7C8G>2.0VG>0.8V5V5VGSDI-12

CONTROL I/O POWER

Logan, U

CR5000 MICROLOGGER

POWER UP

PowerOff

(program control)

tah

SDI-12 12 V

SDM CONNECTIONS

CS7500 CSAT3 SDMINT8 SDMSpeed SDMTrigger

12VGSDM-C1

SDM-C2

SDM-C3G12VGSW-12

POWER OUT

A B C

G H I

J K L

Graph/

char

P R S

T U V

End

- + (

Del

SN:

SW-12

CAUTION DC ONLY

G12V

POWER IN

11 - 16 VDC

GROUND

LUG

pc card status

RS-232

CHARGER INPUT

GROUND LUG

D E F

CURSOR

PgUp

M N O

W X Y

PgDn

< = >

ESC

ALPHA

SHIFT

Spc Cap

BKSPC

$ Q Z

ENTER

POWER IN

POWER GROUND (G), FOR

* / )

Ins

SW-12 12V

MADE IN USA

PCMCIA PC CARD

CardOut (Data Tables and Output)

SWITCHED 12 VOLTS SW-12

PortSet SW12

OV-2

FIGURE OV1-2. CR5000 Panel and Associated Instructions.

OV1.1.2 Signal Grounds ( )

The Signal Grounds ( ) should be used as the reference for Single-ended Analog inputs, Excitation returns, and sensor shield wires.

Signal returns from the CAO and Pulse channels should use the located on the CAO and Pulse terminal strip to minimize current flow through

grounds on the analog terminal strips.

the

OV1.1.3 Power Grounds (G)

The Power Grounds (G) should be used as the returns for the 5V, SW12, 12V, and C1-C8 outputs. Use of the G grounds for these outputs with potentially large currents will minimize current flow through the analog section, which can cause Single-ended voltage measurement errors.

OV1.1.4 Ground Lug

The large ground lug is used to connect a heavy gage wire to earth ground. A good earth connection is necessary fix the ground potential of the datalogger and to send to earth transients that come in on either the G or are shunted to ground via the spark gaps protecting other inputs.

CR5000 Overview

terminals

terminals or

OV1.1.5 Power In

The G and 12V terminals on the unplugable Power In connector are for connecting power from an external battery to the CR5000. These are the only terminals that can be used to input battery power; the other 12V and SW-12V terminals are out only. Power from this input will not charge internal CR5000 batteries. Power to charge the internal batteries (17-28 VDC or 18 VRMS AC) must be connected to the charger input on the side of the LA battery back.

OV1.1.6 Switched 12 Volts SW-12

The SW-12 terminals provide an unregulated 12 volts that can be switched on and off under program control.

OV1.1.7 Switched Voltage Excitation (VX)

Four switched excitation channels provide precision programmable voltages within the ±5 Volt range for bridge measurements. Each analog output will provide up to 50 mA between ±5 V.

OV1.1.8 Switched Current Excitation (IX)

Four Switched Current Excitation channels provide precision current excitations programmable within ±2.5 mA for resistance or bridge measurements.

OV1.1.9 Continuous Analog Outputs (CAO)

Two Continuous Analog Outputs (CAO) with individual outputs under program control for proportional control (e.g., PID algorithm) and waveform generation. Each analog output will provide up to 15 mA between ±5 V.

OV-3

CR5000 Overview

OV1.1.10 Control I/O

OV1.1.11 Pulse Inputs

OV1.1.12 Power Up

There are 8 digital Input/Output channels (0 V low, 5 V high) for frequency measurement, digital control, and triggering.

Two Pulse input channels can count pulses from high-level (5 V square wave), switch closure, or low-level A/C signals.

The CR5000 allows shutting off power under program control. The Power Up inputs allow an external signal to awaken the CR5000 from a powered down state (PowerOff, Section 9). When the CR5000 is in this power off state the ON Off switch is in the on position but the CR5000 is off. If the "<0.5 " input is switched to ground or if the ">2" input has a voltage greater than 2 volts applied, the CR5000 will awake, load and run the “run on power-up” program. If the "< 0.5" input continues to be held at ground while the CR5000 is powered on and goes through its 2-5 second initialization sequence, the CR5000 will not run “run on power-up” program.

OV1.1.13 SDM Connections

The Synchronous Device for Measurement (SDM) connections C1,C2, and C3 along with the adjacent 12 volts and ground terminals are used to connect SDM sensors and peripherals.

OV1.2 Communication and Data Storage

OV1.2.1 PCMCIA PC Card

One slot for a Type I/II/III PCMCIA card. The keyboard display is used to check card status. The card must be powered down before removing it. The card will be reactivated if not removed.

CAUTION

OV1.2.2 CS I/O

OV1.2.3 Computer RS-232

Removing a card while it is active can cause garbled data and can actually damage the card. Do not switch off the CR5000 power while the card is present and active.

A 9-pin serial I/O port supports CSI peripherals.

OV-4

RS-232 Port

OV1.3 Power Supply and AC Adapter

The CR5000 has two base options the low profile without any power supply and the lead acid battery power supply base. The low profile base requires an external DC power source connected to the Power In terminal on the panel.

The battery base has a 7 amp hour battery with built in charging regulator and includes an AC adapter for use where 120 VAC is available (18 VAC RMS output). Charging power can also come from a 17-28 VDC input such as a solar panel. The DCDC18R is available for stepping the voltage up from a nominal 12 volt source (e.g., vehicle power supply) to the DC voltage required for charging the internal battery.

OV2. Memory and Programming Concepts

OV2.1 Memory

The CR5000 has 2MB SRAM and 1MB Flash EEPROM. The operating system and user programs are stored in the flash EEPROM. The memory that is not used by the operating system and program is available for data storage. The size of available memory may be seen in the status file. Additional data storage is available by using a PCMCIA card in the built in card slot.

CR5000 Overview

OV2.2 Measurements, Processing, Data Storage

The CR5000 divides a program into two tasks. The measurement task manipulates the measurement and control hardware on a rigidly timed sequence. The processing task processes and stores the resulting measurements and makes the decisions to actuate controls.

The measurement task stores raw Analog to Digital Converter (ADC) data directly into memory. As soon as the data from a scan is in memory, the processing task starts. There are at least two buffers allocated for this raw ADC data (more under program control), thus the buffer from one scan can be processed while the measurement task is filling another.

When a program is compiled, the measurement tasks are separated from the processing tasks. When the program runs, the measurement tasks are performed at a precise rate, ensuring that the measurement timing is exact and invariant.

Processing Task: Measurement Task:

Digital I/O task

Read and writes to digital I/O ports (ReadI/O, WriteI/O)

Processes measurements

Determines controls (port states) to set next scan Stores data

Analog measurement and excitation sequence and timing Reads Pulse Counters Reads Control Ports (GetPort) Sets control ports (SetPort)

OV-5

CR5000 Overview

OV2.3 Data Tables

The CR5000 can store individual measurements or it may use its extensive processing capabilities to calculate averages, maxima, minima, histogams, FFTs, etc., on periodic or conditional intervals. Data are stored in tables such as listed in Table OV2-1. The values to output are selected when running the program generator or when writing a datalogger program directly.

Table OV2-1. Typical Data Table

TOA4 StnName Temp TIMESTAMP RECORD RefTemp_Avg TC_Avg(1) TC_Avg(2) TC_Avg(3) TC_Avg(4) TC_Avg(5) TC_Avg(6) TS RN degC degC degC degC degC degC degC Avg Avg Avg Avg Avg Avg Avg 1995-02-16 15:15:04.61 278822 31.08 24.23 25.12 26.8 24.14 24.47 23.76 1995-02-16 15:15:04.62 278823 31.07 24.23 25.13 26.82 24.15 24.45 23.8 1995-02-16 15:15:04.63 278824 31.07 24.2 25.09 26.8 24.11 24.45 23.75 1995-02-16 15:15:04.64 278825 31.07 24.21 25.1 26.77 24.13 24.39 23.76

OV3. PC9000 Application Software

PC9000 is a Windows™ application for use with the CR5000. The software supports CR5000 program generation, real-time display of datalogger measurements, graphing, and retrieval of data files.

OV3.1 Hardware and Software Requirements

The following computer resources are necessary:

• IBM PC, Portable or Desktop

• 8 Meg of Ram

• VGA Monitor

• Windows 95 or newer

• 30 Meg of Hard Drive Space for software

• 40 Meg of Hard Drive Space for data

• RS232 Serial Port

OV-6

The following computer resources are recommended:

• 16 Meg of Ram

• 33 MHz 486 or faster

• Mouse

OV3.2 PC9000 Installation

To install the PC9000 Software:

• Start Microsoft Windows

• Insert diskette 1 (marked 1 of 2) in a disk drive.

• From the Program Manager, select F

• Type (disk drive):\setup and press Enter e.g. a:\setup<Enter>

• The setup routine will prompt for disk 2.

ile menu and choose Run

You may use the default directory of PC9000 or install the software in a different directory. The directory will be created for you.

To abort the installation, type Ctrl-C or Break at any time.

OV3.3 PC9000 Software Overview

This overview points out the main PC9000 functions and where to find them. PC9000 has extensive on-line help to guide the user in its operation, run PC9000 to get the details. A CR5000 is not necessary to try out the programming and real time display options; a demo uses canned data for viewing. Without a CR5000, there are no communications with the datalogger; operations such as downloading programs and retrieving data will not function.

Figures OV3-1 and OV3-2 show the main PC9000 menus. The primary functions of PC9000 are accessed from the File, Comm, Realtime, and Analysis selections on the main menu (Figure OV3-1).

CR5000 Overview

OV-7

CR5000 Overview

File Edit Realtime Analysis Tools Collect Display Windows Help

CommLink

Alarms List . . .

ield Monitor . . .

F Virtual M Virtual O

-Y Plotter . . .

istogram . . .

H Fast Fourier T Level Crossing Histogram . . .

et/Set Variable . . .

Display Data Graph 1 . . . Display Data Graph 2

ID2000 . . . Ctrl + I

eter . . .

'Scope . . .

ransform . . .

Select S Select P

Logger C Logger Status . . .

ownload . . . Save and Download Logger F

agnostics

Data Retrieval . . .

cheduled Data Retrieval . . .

eries Linked Station . . . arallel Linked Station . . .

lock . . .

iles . . .

. . .

Realtime Display & Graphing

Display Data in Tables Collected From CR5000. Graphing requires no special processing of the data and provides rapid feedback to the operator.

Collect data from CR5000

PC to CR5000 communications.

CR9000 Program Generator

000 Program Generator

CR5 CR9000 Program Editor . . .

CR5000 Program Editor . . . Open W Open Data Table I

Open D Convert Binary to ASCII File . . .

P Printer Setup . . .

D File Manager . . . E

Exit PC9000

iring Diagram . . .

ata File . . .

rint . . .

OS Shell . . .

xplorer . . .

nfo File . . .

Menu-driven Program Generation.

Direct Editing of Program

View/Edit Wiring Diagram & DataTable Information (Created by Program Generator)

View Data Collected from CR5000

OV3-1. PC9000 Primary Functions

OV-8

CR5000 Overview

File Edit Realtime Analysis Tools Collect Display Windows Help

Undo Ctrl + Z Date & Time Select All Strip Remarks and Spaces Ctrl + S

Cut Ctrl + X Copy Ctrl + C Paste Ctrl + V Delete Delete Line Ctrl + Y Wrap Text Ctrl + W

Go To Line . . . Find Ctrl + F Replace Ctrl + R

OV3-2. PC9000 Editing, Help, and User Preferences

Editing Options for Active Windows

Colors . . . Fonts . . . Defaults . . .

Change fonts and/or Colors for Active Windows.

Tile Horizontal . . . Tile Vertical . . . Cascade . . . Arrange Icons . . .

ork Area Setup . . .

W List of Windows

PC9000 Help Contents . . .

earch PC9000 Help . . .

S CRBasic Help Contents . . .

Search CR Obtaining Technical Support . . . A

bout PC9000 . . .

Software Versions . . .

Basic Help . . .

OV3.3.1 File

OV3.3.2 Edit

Program Generator

Guides the user through a series of menus to configure the measurement types: thermocouple, voltage, bridge, pulse counting, frequency, and others. Creates a CR5000 program, wiring diagram, output table, description, and configuration file.

Program Editor

Create programs directly or edit those created by the program generator or retrieved from the CR5000. Provides context-sensitive help for the CR5000's BASIC-like language.

REALTIME Virtual Meter

Updates up to five displays simultaneously. Choices include analog meter, horizontal and vertical bars, independent scaling/offset, multiple alarms, and rapid on-site calibration of sensors

OV-9

CR5000 Overview

OV3.3.3 Analysis

OV3.3.4 Tools

OV3.3.5 Collect

Virtual Oscilloscope

Displays up to six channels. Time base variable from milliseconds to hours.

X-Y Plotter

Allows comparison of any two measurements in real time.

Data Graphing

Displays up to 16 fields simultaneously as strip charts or two multi-charts with up to 8 traces each. Includes 2D/3D bars, line, log/linear, area, and scatter. Line statistics available for max/min, best fit, mean, and standard deviation. Handles files of unlimited size. Historical graphing requires no special processing of the data and provides rapid feedback to the operator.

Control and Communications

Supports PC to CR5000 communications: clock read/set, status read, program download, and program retrieval.

OV3.3.6 Display

OV3.3.7 Windows

OV3.3.8 Help

Collect data from CR5000 data tables

Configure the font and color scheme in an active window.

Size and arrange windows.

On-line help for PC9000 software.

OV-10

OV4. Keyboard Display

CR5000 Overview

Power Up Screen

Press any key

CAMPBELL

SCIENTIFIC

CR5000 Datalogger

06/18/2000, 18:24:35

CPU: TRIG.CR5

Running.

for Main Menu (except < >)

Data Run/Stop Program File Status Configure, Settings

Adjust contrast with < >

< lighter darker >

Real Time Tables Real Time Custom Final Storage Data Reset Data Tables Graph Setup

New Edit Copy Delete Run Options Directory Format

ROM Version : xxxx OS Version : xxxx OS Date : xxxx OS Signature Serial Number Rev Board Station Name : xxxx Program Name : xxxxx StartTime : xxxxx Run Signature DLD Signature Battery : xxxx

Set Time/Date Settings Display

OV-11

CR5000 Overview

OV4.1 Data Display

Data Run/Stop Program File Status Configure, Settings

Curs or to Data and Press Enter

Real Time Tables Real Time Custom Final Storage Data Reset Data Table Graph Setup

List of Data Tables created by active program

OV-12

All Tables

List of Data Tables created by active program

Graph Type: Scope Scaler: Manual Upper: 0.000000 Lower: 0.000000 Display Val Off Display Max Off Display Mi n Off

OV4.1.1 Real Time Tables

List of Data Tables created by active program. For Example,

Table1 Temps

Public

Cursor to desired Table and press Enter

Tref : 23.0234 TCTemp(1) : 19.6243 TCTemp(2) : 19.3429 TCTemp(3) : 21.2003

TCTemp(3) : Flag(1) : -1.0000 Flag(2) : 0.00000 Flag(3) : 0.00000 Flag(4) : 0.00000

Public Table values can be changed. Cursor to value and press Enter to edit value.

CR5000 Overview

Tref : 23.0234 TCTemp(1) : 19.6243 TCTemp(2) : 19.3429 TCTemp(3) : 21.2003

TCTemp(3)

2 Flag(1) : -1.0000 Flag(2) : 0.00000 Flag(3) : 0.00000 Flag(4) : 0.00000

Press Graph/ Char for Graph of selected field

30.0 22.35

_____ ___ ____ __

20.00

New values are displayed as they are stored.

Scaler Manual

Press Ins for Graph Setup

Upper: 30.000000 Lower: 20.000000 Display Val On Display Max On Display Min On Graph Type Roll

OV-13

CR5000 Overview

)

OV4.1.2 Setting up Real Time Custom Display

List of Data Tables created by active program. For Example,

Table1 Temps

Public

Cursor to desired Table and Press Enter

Tref TCTemp(1) TCTemp(2) TCTemp(3)

TCTemp(3

Flag(1) Flag(2) Flag(3) Flag(4)

Cursor to position for next value and Press Enter

Cursor to desired Field and Press Enter

TCTemp(3) : 24.9496

New values are displayed as they are stored.

: : : : : :

OV-14

OV4.1.3 Final Storage Tables

List of Data Tables created by active program. For Example:

Table1 Temps

CR5000 Overview

Cursor to desired Table and Press Enter

Use Hm (oldest), End (newest), PgUp (older) , PgDn (newer),

←, →, ↑

, and ↓ to move around

in data table.

TimeStamp Record Tref TC(1) TC(2) TC(3) "2000-01-03 00:12:38" 0 21.934 22.8419 "2000-01-03 00:12:39" 1 24.1242 21.8619 21.9173 22.8364 "2000-01-03 00:12:40" 2 24.1242 21.8786 21.9229 22.8364 "2000-01-03 00:12:41" 3 "2000-01-03 00:12:42" 4 "2000-01-03 00:12:43" 5 "2000-01-03 00:12:44" 6 "2000-01-03 00:12:45" 7 "2000-01-03 00:12:46" 8

5 :2000-01-03 00:12:43

Tref TC(1)

24.1242 : 21.8786

24.1242 : 21.8675

21.8675

24.1242 : 21.8675

24.1242 : 21.8398

21.9173 22.8419

21.9173 22.8253

21.9118 22.8364

21.9173 22.8087

21.9173 22.8142

21.9395 22.8253 "2000-01-03 00:12:47" 9 24.1242 21.8176 21.9118 22.8308 "2000-01-03 00:12:48" 10 24.1242 21.8342 21.945 22.8364 "2000-01-03 00:12:49" 11 24.1242 21.8453 21.9506 22.8364

Press Ins for Jump To screen.

Go to Record:

Press Graph/ Char for Graph of selected field.

←, →

Use

, PgUp, PgDn to move cursor and window of data graphed.

press Ins to edit Table Size:

1000 Current Record: 759

30.0 21.87

______ ______ _______ ____ ___ ____ __

20.00

Press Ins for Graph Setup

Scaler Manual Upper: 30.000000 Lower: 20.000000 Display Val On Display Max On Display Min On Graph Type Roll

OV-15

CR5000 Overview

OV4.2 Run/Stop Program

PCCard Display

Data Run/Stop Program File Status Configure, S e ttin g s

Cursor to PCCard and Press Enter

Remove Card Forma t Card Table Status Card Status

CPU: List of Programs No Prog ra m CRD: List of Programs

You may now

remov e the Card.

CR500 0 close s ta ble s first.

All Card Data

Will be Lost!

Proceed? Yes No

List of Data Ta b les on card created by active program

PC Card Status: Battery OK 5Volt Card WP Disabled

OV-16

OV4.3 File Display

Data Run/Stop Program File Status Configure, Settings

Curs o r to File and Press Enter

New Edit Copy Delete Run Options Directory Format

CR5000 Overview

New F i le Name: CPU: .CR5 CRD: .CR5

CPU: CRD:

Copy From

Execute

List of files on CPU or Card.

CPU: Program No Program CRD: Program

CPU:

All programs and other files will be lost!

Proceed? Yes List of Programs No

OV-17

CR5000 Overview

)

OV4.3.1 File: Edit

List of Program files on CPU: or CRD: For Example:

CPU:

TCTEMP.CR5 0 RACE.CR5 0

Cursor to desired Program and Press Enter

The Program Editor in PC9000 is recommended for writing and editing datalogger programs. Changes in the field can be made with the keyboard display.

Save Changes? Yes No

ESC

CR5000 ' TCTemp.CR5

Public TREF,TC(3),FLAG(8) D ataTable (Temps,1,1000)

Sample (1,TREF,IEEE4) Sample (3,TC(),IEEE4)

Edit Directly or Cursor to first character of line and Press Enter

ENTER

Edit Instruction Blank Line Create Block

DataTable (Temps,1,1000)

DataTable (Temps,1,1000

Sample (1,TREF,IEEE4) Sample (3,TC(),IEEE4) EndTable

Press Ins

Edit Instruction parameters with

Cursor down to highlight desired block and press Enter

INSERT

Instruction Function Blank Line Block Insert Off

arameter names and some pick lists:

DataTable

TableName > Temps TrigVar

Size

1000

Insert blank line

Block Commands

Copy Cut Delete

BeginProg Scan(1,sec,3,0)

To insert a block created by this operation, cursor to desired place in

rogram and press Ins.

OV-18

OV4.4 Configure Display

Data Run/Stop Program File Status Configure, Settings

Cursor to Configure, Settings and Press Enter

Set Tim e /Date Settings Display

CR5000 Overview

05/24/2000, 15:10:40 Year 2000 Month 5 Day 24 Hour 15 Minute 10 Set Cancel

Security Enable RS-23 2 Time Out: No CR5000 Off

Light Dark <- * ->

Enter Passwords: Level 1: Level 2: Level 3:

click

Enter

Num

Password

Turn off dis play Back Light Contrast Adjust Display Time O ut: No, Ye s (if yes)

Time out (min) 1

OV-19

CR5000 Overview

OV5. Specifications

Electrical specifications are valid over a -25° to +50°C range unless otherwise specified;testing over -40° to +85°C available as an option, excludes batteries. Non-condensing environment required. Yearly calibrations are recommended to maintain electrical specifications.

PROGRAM EXECUTION RATE

The CR5000 can measure one channel and store the result in 500 µs; all 40 SE* channels can be measured in 8 ms (5 kHz aggregate rate).

ANALOG INPUTS

DESCRIPTION: 20 DF* or 40 SE, individually

configured. Channel expansion provided through AM16/32, AM416, and AM25T Multiplexers.

RANGES, RESOLUTION, AND TYPICAL INPUT NOISE: Basic Resolution (Basic Res) is the A/D

resolution of a single conversion. Resolution of DFM* with input reversal is half the Basic Res. Noise values are for DFM with input reversal;noise is greater with SEM.*

Input Basic 0 Int. 250 µs Int. 20/16.7 ms Int.

Rng (mV) Res (µV) (µV RMS) (µV RMS) (µV RMS)

±5000 167 70 60 30 ±1000 33.3 30 12 6 ±200 6.67 8 2.4 1.2 ±50 1.67 3.0 0.8 0.3 ±20 0.67 1.8 0.5 0.2

ACCURACY

MINIMUM TIME BETWEEN MEASUREMENTS:

COMMON MODE RANGE: ±5 V DC COMMON MODE REJECTION: >100 dB with

NORMAL MODE REJECTION: 70 dB @ 60 Hz

SUSTAINED INPUT VOLTAGE WITHOUT DAMAGE:

INPUT CURRENT: ±2 nA typ., ±10 nA max. @ 50°C INPUT RESISTANCE: 20 GΩ typical ACCURACY OF INTERNAL THERMOCOUPLE

REFERENCE JUNCTION:

†

: ±(0.05% of Reading + Offset) 0° to 40°C ±(0.075% of Reading + Offset) -25° to 50°C ±(0.10% of Reading + Offset) -40° to 85°C Offset for DFM w/input reversal =

Offset for DFM w/o input reversal =

Offset for SEM = 2Basic Res + 10 µV

Zero Integration: 125 µs 250 µs Integration: 475 µs

16.7 ms Integration: 19.9 ms 20 ms Integration: 23.2 ms

input reversal (>80 dB without input reversal)

when using 60 Hz rejection

±16 Vdc

±0.25°C, 0° to 40°C ±0.5°C, -25° to 50°C ±0.7°C, -40° to 85°C

Basic Res +1 µV

2Basic Res + 2 µV

ANALOG OUTPUTS

DESCRIPTION: 4 switched voltage; 4 switched cur-

rent; 2 continuous voltage; switched outputs active only during measurements, one at a time.

RANGE: Voltage (current) outputs programmable

between ±5 V (±2.5 mA)

RESOLUTION: 1.2 mV (0.6 µA) for voltage (current)

outputs

ACCURACY: ±10 mV (±10 µA) for voltage (current)

outputs

CURRENT SOURCING: 50 mA for switched voltage;

15 mA for continuous

CURRENT SINKING: 50 mA for switched voltage;

5 mA for continuous (15 mA w/selectable option)

COMPLIANCE VOLTAGE: ±5 V for switched current

excitation

RESISTANCE MEASUREMENTS

Provides voltage ratio measurements of 4- and 6-wire full bridges, and 2-, 3-, 4-wire half bridges. Direct resistance measurements available with current excitation. Dual-polarity excitation is recommended.

VOLTAGE RATIO ACCURACY

excitation reversal and an excitation voltage of at least 2000 mV.

±(0.04% Reading + Basic Res/4) 0° to 40°C ±(0.05% Reading + Basic Res/4) -25° to 50°C ±(0.06% Reading + Basic Res/4) -40° to 85°C

ACCURACY

†

WITH CURRENT EXCITATION: Assumes input and excitation reversal, and an excitation current, I

±(0.075% Reading + Basic Res/2I ±(0.10% Reading + Basic Res/2I ±(0.12% Reading + Basic Res/2I

†

: Assumes input and

, of at least 1 mA.

x x

) 0° to 40°C

) -25° to 50°C ) -40° to 85°C

PERIOD AVERAGING MEASUREMENTS

DESCRIPTION: The average period for a single

cycle is determined by measuring the duration of a specified number of cycles. Any of the 40 SE analog inputs can be used; signal attenuation and ac coupling may be required.

INPUT FREQUENCY RANGE:

Input Signal (peak to peak) Min. Max.

Rng (mV) Min. Max.

±5000 600 mV 10 V 2.5 µs 200 kHz ±1000 100 mV 2.0 V 5.0 µs 100 kHz

±200 4 mV 2.0 V 25 µs 20 kHz

Maximum signals must be centered around

datalogger ground. RESOLUTION: 70 ns/number of cycles measured ACCURACY: ±(0.03% of Reading + Resolution)

Pulse W. Freq

PULSE COUNTERS

DESCRIPTION: Two 16-bit inputs selectable for switch

closure, high frequency pulse, or low-level ac. MAXIMUM COUNT: 4 x 10 SWITCH CLOSURE MODE:

Minimum Switch Closed Time: 5 ms

Minimum Switch Open Time: 6 ms

Maximum Bounce Time: 1 ms open without

being counted. HIGH FREQUENCY PULSE MODE:

Maximum Input Frequency: 400 kHz

Maximum Input Voltage: ±20 V

Voltage Thresholds: Count upon transition

from below 1.5 V to above 3.5 V at low frequen-

cies. Larger input transitions are required at high

frequencies because of 1.2 µs time constant filter. LOW LEVEL AC MODE:

Internal ac coupling removes dc offsets up to

±0.5 V .

Input Hysteresis: 15 mV

Maximum ac Input Voltage: ±20 V

Minimum ac Input Voltage (sine wave):

(mV RMS) Range (Hz)

20 1.0 to 1000

200 0.5 to 10,000

1000 0.3 to 16,000

counts per scan

DIGITAL I/O PORTS

DESCRIPTION: 8 por ts selectable as binar y inputs or

control outputs. OUTPUT VOLTAGES (no load):high 5.0 V ±0.1 V;

low < 0.1 V OUTPUT RESISTANCE: 330 Ω INPUT STATE: high 3.0 to 5.3 V; low -0.3 to 0.8 V INPUT RESISTANCE: 100 kΩ

EMI and ESD PROTECTION

The CR5000 is encased in metal and incorporates EMI filtering on all inputs and outputs. Gas discharge tubes provide robust ESD protection on all terminal block inputs and outputs. The following European standards apply.

EMC tested and conforms to BS EN61326:1998. Details of performance criteria applied are available

upon request. Warning: This is a Class A product. In a domestic

environment this product may cause radio interference in which case the user may be required to correct the interference at the user’s own expense.

CPU AND INTERFACE

PROCESSOR: Hitachi SH7034 MEMORY: Battery-backed SRAM provides 2 Mbytes

for data and operating system use with 128 kbytes reserved for program storage. Expanded data storage with PCMCIA type I, type II, or type III card.

DISPLAY: 8-line-by-21 character alphanumeric or

128 x 64 pixel graphic LCD display w/backlight.

SERIAL INTERFACES: Optically isolated RS-232

9-pin interface for computer or modem. CSI/O 9-pin interface for peripherals such as CSI modems.

BAUD RATES: Selectable from 1,200 to 115,200 bps.

ASCII protocol is eight data bits, one start bit, one stop bit, no parity.

CLOCK ACCURACY: ±1 minute per month

SYSTEM POWER REQUIREMENTS

VOLTAGE:11 to 16 Vdc TYPICAL CURRENT DRAIN: 400 µA software power

off; 1.5 mA sleep mode; 4.5 mA at 1 Hz (200 mA at 5 kHz) sample rate.

INTERNAL BATTERIES: 7 Ahr rechargeable base

(optional); 1650 mAhr lithium batter y for clock and SRAM backup, 10 years of service typical, less at high temperatures.

EXTERNAL BATTERIES: 11 to 16 Vdc; reverse

polarity protected.

PHYSICAL SPECIFICATIONS

SIZE: 9.8” x 8.3” x 4.5” (24.7 cm x 21.0 cm x 11.4 cm)

WEIGHT: 4.5 lbs (2.0 kg) with low-profile base;

Terminal strips extend 0.4” (1.0 cm).

12.2 lbs (5.5 kg) with rechargeable base

WARRANTY

Three years against defects in materials and workmanship.

*SE(M): Single-Ended (Measurement) *DF(M): Differential (Measurement)

†

Sensor and measurement noise not included.

We recommend that you confirm system

configuration and critical specifications with

Campbell Scientific before purchase.

OV-20

Section 1. Installation and Maintenance

1.1 Protection from the Environment

The normal environmental variables of concern are temperature and moisture. The standard CR5000 is designed to operate reliably from -25 to +50°C (-40°C to +85°C, optional) in noncondensing humidity. When humidity tolerances are exceeded, damage to IC chips, microprocessor failure, and/or measurement inaccuracies due to condensation on the various PC board runners may result. Effective humidity control is the responsibility of the user.

The CR5000 is not hermetically sealed. Two half unit packets of DESI PAK desiccant are located by the batteries. A dry package weighs approximately 19 grams and will absorb a maximum of six grams of water at 40% humidity and 11 grams at 80%. Desiccant packets can be dried out by placing the packets in an oven at 120°C for 16 hours (desiccant only, not the CR5000).

Campbell Scientific offers two enclosures for housing a CR5000 and peripherals. The fiberglass enclosures are classified as NEMA 4X (water-tight, dust-tight, corrosion-resistant, indoor and outdoor use). A 1.25" diameter entry/exit port is located at the bottom of the enclosure for routing cables and wires. The enclosure door can be fastened with the hasp for easy access, or with the two supplied screws for more p e r m anent applications. The white plastic inserts at the corners of the enclosure must be removed to insert the screws. Both enclosures are white for reflecting solar radiation, thus reducing the internal enclosure temperature.

The Model ENC 12/14 fiberglass enclosure houses the CR5000 and one or more peripherals. Inside dimensions of the ENC 12/14 are 14"x12"x5.5", outside dimensions are 18"x13.5"x8.13" (with brackets); weight is 11.16 lbs.

The Model ENC 16/18 fiberglass enclosure houses the CR5000 and several peripherals. Inside dimensions of the ENC 16/18 are 18"x16"x8¾", outside dimensions are 18½"x18¾"x10½" (with brackets); weight is 18 lbs.

1.2 Power Requirements

The CR5000 operates at a nominal 12 VDC. Below 11.0 V or above 16 volts the CR5000 does not operate properly.

The CR5000 is diode protected against accidental reversal of the positive and ground leads from the battery. Input voltages in excess of 18 V may damage the CR5000 and/or power supply. A transzorb provides transient protection by limiting voltage at approximately 20 V.

System operating time for the batteries can be determined by dividing the battery capacity (amp-hours) by the average system current drain. The CR5000 typically draws 1.5 mA in the sleep state (with display off), 4.5 mA with a 1 Hz sample rate, and 200 mA with a 5 kHz sample rate.

1-1

Section 1. Installation and Maintenance

1.3 CR5000 Power Supplies

The CR5000 may be purchased with either a rechargeable lead acid battery or with a low profile case without a battery.

While the CR5000 has a wide operating temperature range (-40 to +85°C optional), the lead acid battery base is limited to -40 to +60°C. Exceeding this

range will degrade battery capacity and lifetime and could also cause permanent damage.

1.3.1 CR5000 Lead Acid Battery BASE

Temperature range: -40° to +60°C Charging voltage: 17 to 24 VDC or 18 V RMS AC

NOTE

In normal operation a charging source should be connected to the base at all times. The CR5000 stops measuring at ~11 V. Battery life is shortened when discharged below 10.5 V.

The CR5000 includes a 12 V, 7.0 amp-hour lead acid battery, an AC transformer (18 V RMS AC), and a temperature compensated charging circuit with a charge indicating LED (Light Emitting Dio de). An AC transformer or solar panel should be connected to the base at all times. The charging source powers the CR5000 while float charging the lead acid batteries. The internal lead acid battery powers the datalogger if the charging source is interrupted. The lead acid battery specifications are given in Table 1.3-1.

The leads from the charging source connect to a wiring terminal plug on the side of the base. Polarity of the leads to the connector does not matter. A transzorb provides transient protection to the charging circuit. A sustained input voltage in excess of 40V will cause the transzorb to limit voltage.

The red light (LED) on the base is on during charging with 17 to 24 VDC or 18 V RMS AC. The switch turns power to the CR5000 on or off. Battery charging still occurs when the switch is o ff.

Should the lead acid batteries require replacement, consult Figure 1.3-1 for wiring.

1-2

Section 1. Installation and Maintenance

LEAD ACID BATTERY REPLACEMENT

6V 7AH

LEAD ACID

BATTERY

6V 7AH

LEAD ACID

BATTERY

RED

BLACK

WHITE

FIGURE 1.3-1. Lead Acid Battery Wiring

Monitor the power supply using datalogger Instruction “Battery”. Incorporate this instruction into data acquisition programs to keep track of the state of the power supply. If the system voltage level consistently decreases through time, some element(s) of the charging system has failed. Battery measures the voltage at the CR5000 electronics, not the voltage of the lead acid battery. The measured voltage will normally be about 0.3 V less than the voltage at the internal or external 12 V input. This voltage drop is on account of a Schottkey diode. External power sources must be disconnected from the CR5000 to measure the actual lead acid battery voltage.

TABLE 1.3-1. CR5000 Rechargeable Battery and AC Transformer

Specifications

Lead Acid Battery

Battery Type Yuasa NP7-6 Float Life @ 25oC 3 years minimum Capacity 7.0 amp-hour Shelf Life, full charge 6 months Charge Time (AC Source) 40 hr full charge, 20 hr 95% charge Operating temperature -40°C to 60°C

AC Transformer

Input: 120 VAC, 60 Hz Isolated Output: 18 VAC 1.2 Amp

There are inherent hazards associated with the use of sealed lead acid batteries. Under normal operation, lead acid batteries generate a small amount of hydrogen gas. This gaseous by-product is generally insignificant because the hydrogen dissipates naturally before build-up to an explosive level (4%) occurs. However, if the batteries are shorted or overcharging takes place, hydrogen gas may be generated at a rate sufficient to create a hazard. Campbell Scientific recommends:

1. A CR5000 equipped with standard lead acid batteries should NEVER be used in applications requiring INTRINSICALLY SAFE equipment.

2. A lead acid battery should not be housed in a gas-tight enclosure.

1-3

Section 1. Installation and Maintenance

1.3.2 Low Profile CR5000

The low profile CR5000 option is not supplied with a battery base. See Section 1.5 and 1.6 for external power connection considerations.

1.4 Solar Panels

Auxiliary photovoltaic power sources may be used to maintain charge on lead acid batteries.

When selecting a solar panel, a rule-of-thumb is that on a stormy overcast day the panel should provide enough charge to meet the system current drain (assume 10% of average annual global radiation, kW/m information, if available, could strongly influence the solar panel selection. For example, local effects such as mountain shadows, fog from valley inversion, snow, ice, leaves, birds, etc. shading the panel should be considered.

Guidelines are available from the Solar e x Corporation for solar panel selection called "DESIGN AIDS FOR SMALL PV POWER SYSTEMS". It provid e s a method for calculating solar panel size based on general site location and system power requirements. If you need help in determining your system power requirements contact Campbell Scientific's Marketing Department.

). Specific site

1.5 Direct Battery Connection to the CR5000 Wiring Panel

Any clean, battery backed 11 to 16 VDC supply may be connected to the 12 V and G connector terminals on the front panel. When connecting external power to the CR5000, first, remove the green power connector from the CR5000 front panel. Insert the positive 12 V lead into the right-most terminal of the green connector. Insert the ground lead in the left terminal. Double check polarity before plugging the green connector into the panel.

Diode protection exists so that an external battery can be connected to the green G and 12 V power input connector, without loading or charging the internal batteries. The CR5000 will draw current from the source with the largest voltage. When power is connected through the front panel, switch control on the standard CR5000 power supplies is by-passed (Figure 1.7-1).

1.6 Vehicle Power Supply Connections

1.6.1 CR5000 with Battery Base

The best way to power a CR5000 with battery base from a vehicle’s 12 V power system is to use the DCDC18R to input the power to the CR5000’s charger input (Figure 1.6-1). With this configuration the CR5000’s batteries are charged when the vehicle power is available. When the vehicle’s voltage is too low or off, the CR5000 is powered from its internal batteries.

1-4

Section 1. Installation and Maintenance

19 20

17 18

15 16

13 14

11 12

910

DIFF

23 24

21 22

H L

DIFF

VX1

VX3

VX2

VX4

CONTROL I/O

Logan tah

CR5000

easurement and Control System

25 26

H L

POWER

CAO1

>2.0V

CAO2

<0.8V

27 28

IX1

ROND

CS I/O

RS-232

COPTER

(OPTICALLY ISOLATED)

pc card

status

DCDC1R

BOOST REGULATOR

V in

V out

(11-16)

G 18V G

MADE IN

USA

29 30

H L

IX2

IX3

IX4

IXR

SDI-12

12V

SDM-C1

SDM-C2

A B C

raph

char

P R S

T V

End

Del

SDM-C3

H L

CONTROL I/O

C1C2C3

12V

POWER OUT

D E

Pgp

N O

PgDn

ESC

H L

SW-12

CRSOR

Spc Cap

BSPC

ENTER

ALPA

SW-12

12V

POWER N 11 - 16 VDC

CATON DC ONL

12V

ADE N SA

H L

39 40

37 38

35 36

33 34

31 32

FIGURE 1.6-1. CR5000 with DCDC18R

It is also possible to use the vehicle's 12 V power system as the primary supply for a CR5000 with a battery base (Figure 1.6-2). When a vehicle’s starting motor is engaged, the system voltage drops considerably below the 11 volts needed for uninterrupted datalogger function. Diodes in the CR5000 in series with the 12 V Power In connector allow the battery base to supply the needed voltage during motor start. The diodes also prevent the separate power systems of the CR5000 and vehicle from attempting to charge each other.

Because this configuration does not charge the CR5000 batteries, it is not recommended.

CR5000

Panel

+12V

FIGURE 1.6-2. Alternate Connect on to Vehicle Power Supply

1-5

Section 1. Installation and Maintenance

1.6.2 CR5000 with Low Profile Base (No Battery)

If a CR5000 without batteries is to be powered from the 12 Volts of a motor vehicle, a second 12 V supply is required. When the starting motor of a vehicle with a 12 V electrical system is engaged, the voltage drops considerably below 11 V, which would cause the CR5000 to stop measurement every time the vehicle is started. The second 12 V supply prevents this malfunction. Figure 1.6-3 shows connecting the two supplies to a CR5000 without a battery base. The diodes allows the vehicle to power the CR5000 without the second supply attempting to power the vehicle.

CR5000

Panel

+12V

FIGURE 1.6-3. Connecting CR5000 without Battery Base to Vehicle

1.7 CR5000 GROUNDING

Grounding of the CR5000 and its peripheral devices and sensors is critical in all applications. Proper grounding will ensure the maximum ESD (electrostatic discharge) protection and higher measurement accuracy.

1.7.1 ESD Protection

An ESD (electrostatic discharge) can originate from several sources. However, the most common, and by far potentially the most destructive, are primary and secondary lightning strikes. Primary lightning strikes hit the datalogger or sensors directly. Secondary strikes induce a voltage in power lines or sensor wires.

The primary devices for protection against ESD are gas-discharge tubes (GDT). All critical inputs and outputs on the CR5000 are protected with GDTs or transient voltage suppression diodes. The GDTs fire at 150 V to allow current to be diverted to the earth ground lug. To be effective, the earth ground lug must be properly connected to earth (chassis) ground. As shown in Figure 1.7-1, the power ground and signal ground are independent lines until joined inside the CR5000.

Power Supply

1-6

Section 1. Installation and Maintenance

Tie analog signal shields and returns to grounds (

) located in analog input terminal strips.

Analog Grounds

Excitation, CAO,

Pulse Counter Grounds ( )

Power Grounds (G)

Tie CAO and pulse-counter returns into grounds ( ) in CAO and pulse-counter terminal strip. Large excitation return currents may also be tied into this ground in order to minimize induced single-ended offset voltages in half bridge measurements.

Tie 5 V, SW-12, 12 V and C1-C8 returns into power grounds (G).

910

11 12

13 14

15 16

17 18

37 38

POWER IN

11 - 16 V

CURSOR

ALPA

SIT

Spc Cap

BSPC

ENTER

19 20 HL

39 40 HL

CAUTION DC ONL

G 12V

5A Thermal fuse

1.5k E20A

GROUND

LUG

CS IO

COPUTER RS-232

(OPTICALL ISOLATED)

Batteries

pc card

status

On/Off

DIFF

VX1

VX2

GC5C6C7C8G>2.0VG>0.8V5V5VGSDI-12

CONTROL I/O POWER

Logan Utah

Ground Plane

23 24

25 26

VX3

VX4

CAO1

CAO2

CR5000 ICROLOGGER

27 28

IX1

IX2

IX3

To CR5000 Electronics

29 30

IX4

31 32

IXR

12VGSDM-C1

33 34

CONTROL I/O

P2C1C2C3C4

SDM-C2

SDM-C3G12VGSW-12

POWER UP

SW12 Control

1.85A

Thermal fuse

A B C

G I

Graph

char

10µf

T U V

P R S

End

)

- (

Ins

Del

35 36

SW-12

0.9A Thermal fuse

D E

PgUp

N O

PgDn

ESC

Star Ground at

Ground Lug

1.85A Thermal fuse

External

Power Input

ADE IN USA

FIGURE 1.7-1. Schematic of CR5000 Grounds

The 9-pin serial I/O ports on the CR5000 are another path for transients to enter and damage the CR5000. Communications devices such a telephone or short-haul modem lines should have spark gap protection. Spark gap protection is often an option with these products, so it should always be requested when ordering. The spark gaps for these devices must be connected to either the CR5000 earth ground lug, the enclosure ground, or to the earth (chassis) ground.

1-7

Section 1. Installation and Maintenance

A good earth (chassis) ground will minimize damage to the datalogger and sensors by providing a low resistance path around the system to a point of low potential. Campbell Scientific recommends that all dataloggers be earth (chassis) grounded. All components of the system (dataloggers, sensors, external power supplies, mounts, housings, etc.) should be referenced to one common earth (chassis) ground.

In the field, at a minimum, a proper earth ground will consist of a 6 to 8 foot copper sheathed grounding rod driven into the earth and connected to the CR5000 Ground Lug with a 12 AWG wire. In low conductive substrates, such as sand, very dry soil, ice, or rock, a single ground rod will probably not provide an adequate earth ground. For these situations, consult the literature on lightning protection or contact a qualified lightning protection consultant. An excellent source of information on lightning protection can be located via the web at http://www.polyphaser.com.

In vehicle applications, the earth ground lug should be firmly attached to the vehicle chassis with 12 AWG wire or larger.

In laboratory applications, locating a stable earth ground is not always obvious. In older buildings, new cover plates on old AC sockets may indicate that a safety ground exists when in fact the socket is not grounded. If a safety ground does exist, it is good practice to verify that it carries no current. If the integrity of the AC power ground is in doubt, also ground the system through the buildings, plumbing or another connection to earth ground.

1.7.2 Effect of Grounding on Measurements: Common Mode Range

The common mode range is the voltage range, relative to the CR5000 ground, within which both inputs of a differential measurement must lie in order for the differential measurement to be made correctly. Common mode range for the CR5000 is ±5.0 V. For example, if the high side of a differential input is at 2 V and the low side is at 0.5 V relative to CR5000 ground, a measurement made on the ±5.0 V range would indicate a signal of 1.5 V. However, if the high input changed to 6 V, the common mode range is exceeded and the measurement may be in error.

Common mode range may be exceeded when the CR5000 is measuring the output from a sensor which has its own grounded power supply and the low side of the signal is referenced to the sensors power supply ground. If the CR5000 ground and the sensor ground are at sufficiently different potentials, the signal will exceed the common mode rang e. To solve this problem, the sensor power ground and the CR5000 ground should be connected, creating one ground for the system.

In a laboratory application, where more than one AC socket may be used to power various sensors, it is not safe to assume that the power grounds are at the same potential. To be safe, the ground of all the AC sockets in use should be tied together with a 12 AWG wire.

1-8

Section 1. Installation and Maintenance

1.7.3 Effect of Grounding on Single-Ended Measurements

Low-level single-ended voltage measurements can be problematic because of ground potential fluctuations. The grounding scheme in the CR5000 has been designed to eliminate ground potential fluctuations due to changing return currents from 12 V, SW-12, 5 V, and the control ports. This is accomplished by utilizing separate signal grounds ( advantage of this design, observe the following grounding rule:

) and power grounds (G). To take

NOTE

Always connect a device’s ground next to the active terminal associated with that ground.

Examples:

1. Connect 5 Volt, 12 Volt, and control grounds to G terminals.

2. Connect excitation grounds to the closest terminal block.

3. Connect the low side of single-ended sensors to the nearest the analog input terminal blocks.

4. Connect shield wires to the nearest terminal blocks.

If offset problems occur because of shield or ground leads with large current flow, tying the problem leads into the

and pulse-counter channels should help. Problem leads can also be tied directly to the ground lug to minimize induced single-ended offset voltages.

terminal on the analog input

terminals next to the excitation, CAO,

1.8 Powering Sensors and Peripherals

terminal on the excitation

terminal on

The CR5000 is a convenient source of power for sensors and peripherals requiring a continuous or semi-continuous 5 VDC or 12 VDC source. The CR5000 has 2 continuous 12 Volt (12V) supply terminals, 2 switched 12 Volt (SW-12) supply terminals, and 2 continuous 5 Volt (5V) supply terminals. Voltage on the 12V and SW-12 terminals will change with the CR5000 supply voltage. The 5V terminal is regulated and will always remain near 5 Volts (±4%)so long as the CR5000 supply voltage remains above 11 Volts. The 5V terminal is not suitable for resistive bridge sensor excitation. Table 1.8-1 shows the current limits of the 12 Volt and 5 Volt ports. Table 1.8-2 shows current requirements for several CSI peripherals. Other devices normally have current requirements listed in their specifications. Current drain of all peripherals and sensors combined should not exceed current sourcing limits of the CR5000.

1-9

Section 1. Installation and Maintenance

Make certain that the primary source of power for the CR5000 can sustain the current drain for the period of time required. Contact a CSI applications engineer for help in determining a power budget for applications that approach the limits of a given power supply’s capabilities. Be particularly cautious about any application using solar panels and cellular telephone or radio, applications requiring long periods of time between site visits, or applications at extreme temperatures.

Table 1.8-1 Current Sourcing Limits

Terminals Current Source Limit

SW12 < 900 mA @ 20°C

< 729 mA @ 40°C < 630 mA @ 50°C < 567 mA @ 60°C < 400 mA @ 80°C

12V + SW12 < 1.85 A @ 20°C

< 1.50 A @ 40°C < 1.30 A @ 50°C < 1.17 A @ 60°C < 0.85 A @ 80°C

5V + CSI/O < 200 mA

TABLE 1.8-2. Typical Current Drain for Some CR5000 Peripherals

Typical Current Drain (mA)

Peripheral Quiescent Active

AM25T .5 1 COM100 .5 1.8 COM200 Phone Modem 0.0012 140 SDM-INT8 0.4 6.5

1.9 Controlling Power to Sensors and Peripherals

Controlling power to an external device is a common function of the CR5000.

Many devices can conveniently be controlled with the SW-12 (Switched 12 Volt) terminals on the CR5000. Table 1.8-1 shows the current available from SW-12 port.

Applications requiring more control channels or greater power sourcing capacity can usually be satisfied with the use of Campbell Scientific’s A21REL-12 Four Channel Relay Driver, A6REL-12 Six Channel Relay Driver, SDM-CD16AC 16 Channel AC/DC Relay Module, or by using the control (C1-C8) ports as described in Section 1.9.1

1-10

Section 1. Installation and Maintenance

1.9.1 Use of Digital I/O Ports for Switching Relays

Each of the eight digital I/O ports can be configured as an output port and set low or high (0 V low, 5 V high) using the PortSet or WriteIO instructions. A digital output port is normally used to operate an external relay driver circuit because the port itself has a limited drive capability (2 .0 mA minimum at 3.5 V).

Figure 1.9-1 shows a typical relay driver circuit in conjunction with a coil driven relay which may be used to switch external power to some device. In this example, when the control port is set high, 12 V from the datalogger passes through the relay coil, closing the relay which completes the power circuit to a fan, turning the fan on.

In other applications it may be desirable to simply switch power to a device without going through a relay. Figure 1.9-2 illustrates a circuit for switching external power to a device without going through a relay. If the peripheral to be powered draws in excess of 75 mA at room temperature (limit of the 2N2907A medium power transistor), the use of a relay (Figure 1.9-1) would be required.

Other control port activated circuits are possible for applications with greater current/voltage demands than shown in Figures 1.9-1 and 2. For more information contact a Campbell Scientific applications engineer.

FIGURE 1.9-1. Relay Driver Circuit with Relay

1-11

Section 1. Installation and Maintenance

FIGURE 1.9-2. Power Switching without Relay

1.10 Maintenance

The CR5000 power supplies require a minimum of routine maintenance.

When not in use, the rechargeable supply should be stored in a cool, dry environment with the AC charger active.

1.10.1 Desiccant

The CR5000 is shipped with desiccant to reduce humidity. Desiccant should be changed periodically. To prevent corrosion in uncontrolled or condensing atmospheres, the CR5000 must be placed inside a weather tight instrument enclosure with desiccant. Do not completely seal the enclosure if lead acid batteries are present. Hydrogen gas generated by the batteries may build up to an explosive concentration.

1.10.2 Replacing the Internal Battery

CAUTION

Misuse of the lithium battery or installing it improperly can cause severe injury. Fire, explosion, and severe burn hazard! Do not recharge, disass emble, heat above 100°C (212°F), solder directly to the cell, incinerate, nor expose contents to water.

The CR5000 contains a lithium battery that operates the clock and SRAM when the CR5000 is not powered. The CR5000 does not draw any power from the lithium battery while it is powered by a 12 VDC supply. In a CR5000 stored at room temperature, the lithium battery should last approximately 10 years (less at temperature extremes). Where the CR5000 is powered most or all of the time the lithium cell should last much longer.

1-12

Section 1. Installation and Maintenance

While powered from an external source, the CR5000 measures the voltage of the lithium battery daily. This voltage is displayed in the status table (Section

1.6) A new battery will have approximately 3.6 volts. The CR5000 Status

Table has a “Lithium Battery” field. This field is either “ True” (battery is good) or “False” (replace battery). If the lithium cell is removed or allowed to discharge below the safe level, the CR5000 will still operate correctly while powered. Without the lithium battery, the clock will reset and data will be lost when power is removed.

A replacement lithium battery can be purchased from Campbell (p art number

13497). Table 1.10-1 lists the specifications of the battery.

Table 1.10-1 CR5000 Lithium Battery Specifications

Model Tadiran TL-5955 (3.6 V)

Capacity 1650 mAh self discharge rate 1%/year @ 20°C Diameter 14.5 mm Length 33.5 mm Operating temperature range -55°C to 85°C

The CR5000 must be partially disassembled to replace the lithium cell.

The battery is replaced as shown in Figures 1.10-4 to 1.10-6. The battery is held in place by a band clamp. It can be removed by gently prying the band from the sides of the battery holder.

SANYO

FIGURE 1.10-4. Removal of CR5000 back plate and lithium battery

location.

1-13

Section 1. Installation and Maintenance

The new cell is placed into the battery holder, observing the polarity markings on the holder. Replace the band clamp, ensuring that both ends snap securely into the battery holder.

BATTERY2

(datalogger/cr5000)

FIGURE 1.10-5. Loosening of band clamp.

SANYO

1-14

Section 1. Installation and Maintenance

FIGURE 1.11-6. Removal of band clamp and battery.

SANYO

1-15

Section 1. Installation and Maintenance

This is a blank page.

1-16

Section 2. Data Storage and Retrieval

The CR5000 can store individual measurements or it may use its extensive processing capabilities to calculate averages, maxima, minima, histograms, FFTs, etc., on periodic or conditional intervals. Data are stored in tables. For simplicity, the PC9000 program generator allows a maximum of three data tables (in the native language up to 30 data tables can be created). The number of tables and the values to output in each table are selected when running the program generator (Overview) or when writing a datalogger program directly (Sections 4 – 9).

2.1 Data Storage in CR5000

There are two areas for data storage on the CR5000:

Internal Static RAM PCMCIA PC Card

Internal RAM is used as either the sole storage area for a data table or as a buffer area when data are sent to PC card.

When the CR5000 gets a request for data that is stored on a PC card, the CR5000 only looks for the data in the PC card when the oldest data are requested or if the data are not available in internal RAM.

In the CRBASIC program, the DataTable instr uction sets the size of the data table or buffer area. A data table can be stored in a PC card by including the CardOut instruction within the data table declaration. A maximum of 30 tables can be created by the program.

2.1.1 Internal Static RAM

Internal RAM is used as either the sole storage area for a data table or as a buffer area when data are sent to a PC card. The only limit on the number of tables is the available memory. Internal RAM is battery backed. Data remain in memory when the CR5000 is powered down under program control. Data in RAM are erased when a different program is loaded and run.

There are 2 Mbytes of SRAM. Some of this is used by the operating system and for program storage. The rest is available for data storage. When a new program is compiled, the CR5000 checks that there is adequate space in SRAM for the data tables; a program that requests more space than is available will not run.

2.1.2 PCMCIA PC Card

The CR5000 has a built in PC card slot for a Type I, Type II, or Type III PCMCIA card. PCMCIA PC Cards allows expanding the CR5000’s storage capacity. SRAM and ATA cards are supported. A program can send a maximum of 30 data tables to PC cards.

2-1

Section 2. Data Storage and Retrieval

When a new program is compiled that sends data to the PC card, the CR5000 checks if a card is present and if the card has adequate space for the data tables. If the card has adequate space, the tables will be allocated an d the CR5000 will start storing data to them. If there is no card or if there is not enough space, the CR5000 will warn that the card is not being used and will run the program, storing the data in SRAM only. When a card with enough available memory is inserted the CR5000 will create the data tables on the card and store the data that is accumulated in SRAM (Section 2.3.4).

Data stored on cards can be retrieved through the communication link to the CR5000 or by removing the card and inserting it in a PC card slot in a computer. The PCMCIA interface is much faster than the communication link. With large files transferring the PC card is faster than collecting the data over the link.

The CR5000 uses an MS DOS format for the PC cards. Cards can be formatted in a PC or in the CR5000.

2.2 Internal Data Format

TABLE 2.2-1 CR5000 DATA TYPES

Data Type Size Range Resolution LONG 4 bytes -2,147,483,648 to +2,147,483,647 1 bit (1) IEEE4 4 bytes 1.8 E -38 to 1.7 E 38 24 bits (about 7 digits) FP2 2 bytes -7999 to +7999 13 bits (about 4 digits)

Data are stored internally in a binary format. Variables and calculations are performed internally in IEEE 4 byte floating point with some operations calculated in double precision. There are two data types used to store data: IEEE4 four byte floating point and Campbell Scientific two byte floating point (FP2). The data format is selected in th e instruction that outputs the data. Within the CR5000, time is stored as integer seconds and nanoseconds into the second since midnight, the start of 1990. While IEEE 4 byte floating point is used for variables and internal calculations, FP2 is adequate for most stored data. Campbell Scientific 2 byte floating point provides 3 or 4 significant digits of resolution, and requires half the memory space as IEEE 4 byte floating point (2 bytes per value vs 4).

TABLE 2.2-2. Resolution and Range Limits of FP2 Data

Zero Minimum Magnitude Maximum Magnitude

0.000 ±0.001 ±7999.

The resolution of FP2 is redu ced to 3 significant digits when the first (left most) digit is 8 or greater (Table 2.2-2). Thus, it may be necessary to use IEEE4 output or an offset to maintain the desired resolution of a measurement. For example, if water level is to be measured and output to the nearest 0.01 foot, the level must be less than 80 feet for low resolution output to display the

0.01 foot increment. If the water level is expected to range from 50 to 90 feet the data could either be output in high resolution or could be offset by 20 feet (transforming the range to 30 to 70 feet).

2-2

Absolute Value Decimal Location

80 - 799.9 XXX.X

800 - 7999. XXXX.

2.3 Data Collection

Data can be transferred into a computer using PC9000 via a communications link or by transferring a PC card from the PC9000 to the computer. There are three ways to collect data via a link to the CR5000 using the PC9000 software. The collect menu is used to collect any or all stored data and is used for most archival purposes.

On each of the RealTime screens, there is a "write file" check box. Data stored to the table while the box is checked are also stored in a file on the PC.Logger Files under the T PC card. This can be used to retrieve a data file.

Section 2. Data Storage and Retrieval

TABLE 2.2-3 FP2 D ecimal Location

0 - 7.999 X.XXX 8 - 79.99 XX.XX

ools menu has the option of retrieving a file from a

When the CR5000 is used without a computer in the field, or large data files are collected on a PC card, the PC card can be transported to the computer with the data on it.

The format of the data files on the PC card is different than the data file formats created by PC9000 when the collect or write file options are used. Data files retrieved from the Logger Files screen or read directly from the PC card generally need to be converted into another format to be used (Section

2.3.4.2).

2.3.1 The Collect Menu

When Retrieve Data is selected in the Collect menu, PC9000 displays the Collect Data dialog box (Figure 2.3.1). The station name (may be entered by the user when a program is downloaded) is retrieved from the connected CR5000 and shown at the top.

2-3

Section 2. Data Storage and Retrieval

FIGURE 2.3.1. Collect Data Dialog Box

2.3.1.1 File Type

ASCII With Time – Click here to store the data as an ASCII (TOA5, Section

2.4) file. Each record will be date and time stam ped.

Binary With Time – Click here to store the data as a binary file (TOB1, Section 2.4). Each record will be date and tim e stamped.

ASCII Without Time – Click here to store the data as an ASCII file (TOA5, Section 2.4). There will be no date and tim e stamps.

Binary Without Time – Click here to store the data as a binary file (TOB1, Section 2.4). There will be no date and tim e stamps.

2.3.1.2 Collection Method

All Records, Create New File – Collects the entire table stored in the CR5000. PC9000 gets the current record number from the table in the CR5000 and then retrieves the oldest record in the table up to the current record number. The number in the file name is incremented to create the file name in which the data are stored.

2-4

Section 2. Data Storage and Retrieval

Since Last, Create New File – Click here to save new data in a new file. PC9000 searches for the last file with the Root name, gets the last record number from that file, then the current record from the table in the CR5000, and requests all records in between those numbers from the CR5000. The number in the file name is incremen ted to create the file name in which the data are stored.

Since Last, Append To File – Click here to append retrieved data to the end of the named file. PC9000 searches for the last file with the Root name, gets the last record number from that file, then the current record from the table in the CR5000, and requests all records in between those numbers from the CR5000. The data are appended to the existing file.

Number of Records, Create New File Collects the number of records entered in Num of Recs box. Retrieves that many records back from the current record number. The number in the file name is incremented to create the file name in which the data are stored.

Num of Recs – Enabled when Number of Records, Create New File is checked. Enter the number of records back from the current record number to retrieve.

2.3.1.3 Table Selection

All Tables – When the All Tables box is checked, all data tables except the Public and Status tables are collected when collection is executed. The data from each table are stored in a file with the table name and increment number (see Table naming). This is a convenient method of collecting all data from the CR5000. The first time data are collected, all data is checked and the file type and collection method are selected. PC9000 remembers the settings, and on subsequent collections the operator only needs to click on execute.

Stream – acts the same as Write file for the selected Table Name (Section

2.3.2).

Table Name – When "All tables" is not checked, a single data table can be selected for collection. The Table Name box is used to select the table to be retrieved.

Reset Table – Resetting a data table erases all data in the table and sets the record number back to 0. Unless the table is configured as fill and stop by the CR5000 program, it is not necessary to reset the table because the "Since Last" collection option can be used to get only the new data. If the table is configured as fill and stop, it stops collecting data once full and must be reset before more data can be collected. Use with caution.

2.3.1.4 File Control

The default naming for a file stored to disk is to use the data table name appended with a 2 digit number and the extension .DAT. If the table name is longer than 6 characters, it is truncated. For example, the table name EVENTS is stored as EVENTS00.DAT. A table named CYLTEMP is stored as CYLTEM00.DAT.

2-5

Section 2. Data Storage and Retrieval

When the file collection options that create a new file are used, each time a table is collected, the 2 digit number is incremented (e.g., EVENTS00.DAT, EVENTS01.DAT, EVENTS03.DAT ...). PC9000 searches the selected directory and adds 1 to the number of the highest numbered file of the matching name to create the new name.

When the new data are to be appended to the existing file, PC9000 searches the selected directory for the highest numbered file of the matching name, and appends the data to that file.

Change File – Press the Change File button to change the n a me of the file to be stored on disk. This is not possible when "All Tables" is selected.

Set Path – Press here to select a different disk or directory to write the files to.

EXECUTE – Press here to begin collecting data.

2.3.1.5 Status Messages

TABLE SIZE – Shows the size (in records) of the table highlighted in the Table Name box above.

COLLECTION RANGE – Displays the range of records to be collected. More records than the last number in this range may actually be retrieved.

LOGGER MESSAGE – Displays messages from the CR5000.

2.3.2 RealTime Write File

This feature is provided to allow the user to start and stop collecting data for some event without leaving the real-time window. Check this box to write the current table to a file in the computer. Writing begins with the current record and continues until the Write File box is unchecked or until the window is closed.

This collection method requires that the PC is connected to the CR5000 while the data are collected. Because the beginning and end points of the data file are roughly determined by when the box is checked, this is best suited to collecting data when the user rather than the measurements determine when data should be collected.

The bottom line of the screen will periodically display the current record being written. The name of the file written will be the f ir st six characters of the table name plus 2 digits and an extension of .DAT. If the table name is MAIN then the first file created will be named MAIN00.DAT. The nex t file will be named MAIN01.DAT and so on. It takes a little tim e to open the file so be sure it is opened in advance of the event you want to store.

2-6

The file is written to every 1 second so it is important the table size be large enough to store sufficient data between writes. During each write operation, the data may not be updated on the screen but this will not effect the stored data.

2.3.3 Logger Files Retrieve

Logger Files under the PC9000 tools menu allows the user to check the programs stored in CPU Flash memory and the files stored on the PCMCIA cards. Any of the files shown in logger files can be copied to the computer by highlighting the file and pressing the retrieve button. Data files in the CR5000 CPU and Flash memory are not shown.

The retrieved data file is stored on the co mputer in the same form that it was stored on the PC card (TOB2). This format generally needs to be converted to another format for analysis (Section 2.3.4)

Section 2. Data Storage and Retrieval

2.3.4 Via PCMCIA PC Card

When the CR5000 is used without a computer in the field, or large data files are collected on a PC card, the PC card can be transported to the computer with the data on it.

2.3.4.1 Inserting a PC Card

A card inserted in the PCMCIA slot when no program is running or when a program is running that does not use the PC card does not cause a response

FIGURE 2.3-2. Logger Files Dialog Box

2-7

Section 2. Data Storage and Retrieval

from the CR5000. When a new program is compiled that sends data to the PC card, the CR5000 checks if a card is present and if the card has adequate space for the data tables. If the card has adequate space, the tables will b e allo cated and the CR5000 will start storing data to them.

When the running program sends data to the card, and a card is inserted, the CR5000 will detect the card and display a message.

A card that has no data tables files with the same names as those created by the program causes the message:

If the card has existing data table files that match those created by the program there is the message:

New Card. Start Storing? No Yes

Tables on Card Must be Reset. Proceed? No Yes Same Card

The “No” option [do not start storing data to the card] allows using the CR5000 to check the card and to erase files or to format the card if necessary.

The “Yes” option is to start storing data right away, resetting any tables with the same name that exist on the card. This is the option that is generally used when a blank (but formatted) card is inserted or when a card is reinserted after transferring data to a computer.

The “Same Card” option is only available if the data table header matches the program exactly and the program has already run with a card. This option allows removing the card to read it and then returning it to the CR5000 and having the new data appended to the data already on the card. If you choose to use this option be aware that if the CR5000 overwrites its buffer while the card is out, there will be a gap in the data on the car d.

2.3.4.2 Removing Card from CR5000

The PC Card Status LED just above the PC card door is lit when the card is being written to.

CAUTION

Removing a card while it is active can cause garbled data and can actually damage the card. Do not switch off the power while the cards are present and active.

2-8

To remove a card, use the keyboard display to go to the PcCard menu; move the cursor to “Remove Card : and press Enter. The Status will show “You may now remove the card”. Remove the card. Th e card will be reactivated if not removed.

When the PC card is inserted in a computer, the data files can be copied to another drive or used directly from the PC card just as one would from any other disk. In most cases, however, it will be necessary to convert the file format before using the data.

2.3.4.3 Converting File Format

The CR5000 stores data on the PC card in TOB2 Format. TOB2 is a binary format that incorporates featu r es to improve reliability of the PC Cards. TOB2 allows the accurate determination of each record’s time without the space required for individual time stamps.

When TOB2 files are converted to another format, the number of records may be greater or less than the number requested in the data table declaration. There are always at least two additional frames of data allocated. When the file is converted these will result in additional records if no lapses occurred. If more lapses occur than were anticipated, there may be fewer records in the file than were allocated.

PC9000’s file converter will convert TOB1 or TOB2 files to other formats. The Convert Data Files option is in the File Menu. The options for TOB2 appear after the name of the file to convert has been selected (Figure 2.3-3.)

Section 2. Data Storage and Retrieval

FIGURE 2.3-3 File Conversion Dialog Box

2-9

Section 2. Data Storage and Retrieval

"File Format","Station","Logger","Serial No.","OS Ver","DLD File","DLD Sig","Table Name" "TIMESTAMP","RECORD","Field Name","Field Name","Field Name" "TS","RN","Field Units","Field Units","Field Units" "","","Processing","Processing","Processing" "Field Data Type","Field Data Type","Field Data Type","Field Data Type","Field Data Type"

timestamp,record number,field data , field data,field data,

FIGURE 2.4.1 Header Information

2.4 Data Format on Computer

The format of the file stored on disk can be either ASCII or Binary depending on the file type selected in the collect data dialog box. Files collected from a real time window are always stored in ASCII format.

2.4.1. Header Information

Every data file stored on disk has an ASCII header at the beginning. The header gives information on the format, datalogger and program used to collect the data. Figure 2.4.1 is a sample header where the text in the header is a generic name for the information contained in the header. The entries are described following the figure.

File Format

The format of the file on disk. TOA5 is an ASCII format. TOB1 is a Binary format. This information is used by the historical graphing and file conversion functions of PC9000.

Station Name

The station name set in the logger that the data was collected from.

Logger Model

The datalogger model that the data was collected from.

Logger Serial Number

The serial number of the logger that the data was collected from. This is the serial number of the CR5000 CPU.

Operating System Version

The version of the operating system in the logger that the data was collected from.

DLD File

The name of the DLD file that was running when the data were created.

DLD Signature

The signature of the DLD file that created the data.

2-10

Table Name

The data table name.

Section 2. Data Storage and Retrieval

Field Name

The name of the field in the data table. This name is created by the CR5000 by appending underscore ( _ ) and a three character mnemonic for the output processing.

Field Units

The units for the field in the data table. Units ar e assigned in the program with the units declaration.

Field Processing

The output processing that was used when the field was stored. Smp = Sample Max = Maximum Min = Minimum Avg = Average

Field Data Type

This header line is only in TOB1 binary f ormat and identifies the data type for each of the fields in the data table.

UINT4 = Unsigned 4 byte integer IEEE4 = 4 byte floating point

Time Stamp

This field is the date and time stamp for this r ecord. It indicates the time, according to the logger clock, that each record was stored.

Record Number

This field is the record number of this record. The number will increase up to 2E32 and then start over with zero. The record number will also start over at zero if the table is reset.

Field Data

This is the data for each of the fields in the record.

2.4.2 TOA5 ASCII File Format

The following is a sample of a file collected as ASCII with time stamps.

"TOA5","Bob's9K","CR5000","1048575","1.00","EXPLDAT.DLD","4339","Temp" "TIMESTAMP","RECORD","RefTemp_Avg","TC_Avg(1)","TC_Avg(2)","TC_Avg(3)","TC_Avg(4)" "TS","RN","degC","degC","degC","degC","degC" "","","Avg","Avg","Avg","Avg","Avg" "1995-09-19 14:31:43.84",458,29.94,25.6,25.36,25.48,25.4 "1995-09-19 14:31:43.85",459,29.93,25.6,25.36,25.41,25.35

2-11

Section 2. Data Storage and Retrieval

The following is an example of how the above data might look when imported into a spread sheet.

TOA5 Bob's9K CR5000 1048575 1.00 EXPLDAT.

DLD TIMESTAMP RECORD RefTemp_Avg TC_Avg(1) TC_Avg(2) TC_Avg(3) TC_Avg(4) TS RN degC degC degC degC degC

Avg Avg Avg Avg Avg 1995-09-19 14:31:43.84 458 29.94 25.6 25.36 25.48 25.4 1995-09-19 14:31:43.85 459 29.93 25.6 25.36 25.41 25.35

This is the same data table collected as ASCII without time stamps

"TOA5","Bob's9K","CR5000","1048575","1.00","EXPLDAT.DLD","4339","Temp" "RefTemp_Avg","TC_Avg(1)","TC_Avg(2)","TC_Avg(3)","TC_Avg(4)" "degC","degC","degC","degC","degC" "Avg","Avg","Avg","Avg","Avg"

29.94,25.6,25.36,25.48,25.4

29.93,25.6,25.36,25.41,25.35 And again, an example of how the above data might look when imported into a

spread sheet.

TOA5 Bob's9K CR5000 1048575 1.00 EXPLDAT.

DLD RefTemp_Avg TC_Avg(1) TC_Avg(2) TC_Avg(3) TC_Avg(4) degC degC degC degC degC Avg Avg Avg Avg Avg

29.94 25.6 25.36 25.48 25.4

29.93 25.6 25.36 25.41 25.35

4339 Temp

2.4.2 TOB1 Binary File Format

This is a sample of a file collected as Binary with time stamps.

TOB1,Bob's9K,CR5000,1048575,1.00,EXPLDAT.DLD,4339,Temp SECONDS,NANOSECONDS,RECORD,RefTemp_Avg,TC_Avg(1),TC_Avg(2),TC_Avg(3),TC_Avg(4) SECONDS,NANOSECONDS,RN,degC,degC,degC,degC,degC ,,,Avg,Avg,Avg,Avg,Avg UINT4,UINT4,UINT4,IEEE4,IEEE4,IEEE4,IEEE4,IEEE4 (data lines are binary and not directly readable )

This is an example of binary without time stamps.

TOB1,Bob's9K,CR5000,1048575,1.00,EXPLDAT.DLD,4339,Temp RefTemp_Avg,TC_Avg(1),TC_Avg(2),TC_Avg(3),TC_Avg(4) degC,degC,degC,degC,degC Avg,Avg,Avg,Avg,Avg IEEE4,IEEE4,IEEE4,IEEE4,IEEE4 (data lines are binary and not directly readable )

2.4.3 TOB2 Binary File Format

The TOB2 binary format has a header similar to the other formats. TOB2 data is stored in fixed size “frames” that generally contain a number of records. The size of the frames is a function of the record size. The frames are time

2-12

Section 2. Data Storage and Retrieval

stamped, allowing the calculation of time stamps for their records. If there is a lapse in periodic interval records that does not occur on a frame boundary, an additional time stamp is written within th e frame and its occurrence noted in the frame boundary. This additional time stamp takes up space that would otherwise hold data.

2-13

Section 2. Data Storage and Retrieval

This is a blank page.

2-14

Section 3. CR5000 Measurement Details

3.1 Analog Voltage Measurement Sequence

The CR5000 measures analog voltages with either an integrate and hold or a sample and hold analog to digital (A/D) conversion. The A/D conversion is made with a 16 bit successive approximation technique which resolves the signal voltage to approximately one part in 60,000 of the full scale range. The maximum conversion rate is 5000 per second or one measurement every 200 µs (10,000 measurements per second on a single channel).

The timing of CR5000 measurements is precisely controlled. The measurement schedule is determined at compile time and loaded into memory. This schedule sets interrupts that drive the measur ement task.

Using two different voltage measurement instructions with the same voltage range takes the same measurement time as using one instruction with two repetitions. (This is not the case in the CR10X, 21X, CR23X and

CR7 dataloggers where there is always a setup time for each instruction.) There are four parameters in the measurement instructions that may vary the

sequence and timing of the measurement. These are options to measure and correct the ground offset on single-ended measurements each time measurements are made (MeasOfs), reverse the high and low differential inputs (RevDiff), to set the time to allow the signal to settle between switchin g to a channel and making a measurement (SettlingTime), and the length of time to integrate a measurement (Integ), and to reverse the polarity of excitation voltage (RevEx).

3.1.1 Voltage Range

The CR5000 has 5 fixed voltage ranges and autorange. The 16 bit A/D has a resolution of 1 part in 2 the A/D is applied to a range approxim ately 9% greater than the Full Scale Range resulting in the 1 part in 60,000 resolution over the FSR. For example, on the ±20 mV range the full scale range is 40 mV [20 - (-20)] and the resolution is two thirds of a microvolt; 0.04 / 0.000000667 = 60,000. The smaller the voltage range, the b etter the absolute resolution. In general, a measurement should use the smallest fixed voltage range that will accommodate the full scale output of the sensor being measured. If the voltage exceeds the range, the CR5000 indicates the overrange by returning Not-ANumber (NAN) for the measurement.

For signals that do not fluctuate too rapidly, AutoRange allows the CR5000 to automatically choose the voltage range to use. AutoRange causes the CR5000 to make two measurements. The first measurement determines the range to use. It is made with no integration on the ±5000 mV range. The second measurement is made on the appropriate range using the integration specified in the instruction. Both measurements use the settling time programmed in the instruction. AutoRange optimizes resolution but takes longer than a measurement on a fixed range, because of the two measurements required.

(65,536). To allow for some overrange capabilities

3-1

Section 3. CR5000 Measurement Details

An AutoRange measurement will return Not-A-Number if th e voltage exceeds the range picked by the first measurement. To avoid problems with a signal on the edge of a range, AutoRange selects the next larger range when the signal exceeds 90% of a range.

AutoRange is very good for a signal that occasionally exceeds a particular range, for example, a Type J thermocouple that most of the time will be less than 360 °C (±20 mV range) but will occasionally see temperatu r es as h ig h as 400 °C (±50 mV range, Table 3.4-2). AutoRange should not be used for rapidly fluctuating signals, particularly those whose signal traverses several voltage ranges rapidly because of the possibility that the signal could change ranges between the range check and the actual measurement.

3.1.2 Reversing Excitation or the Di ffer ential Input

Reversing the excitation polarity or the differential input are techniques to cancel voltage offsets that are not part of the signal. For example, if there is a +5 µV offset in the measurement circuitry, a 5 mV signal will be m easured as

5.005 mV. When the input is reversed, the measurement will be

-4.995 mV. Subtracting the second measurement from the first and dividing by 2 gives the correct answer: 5.005-(-4.995)=10, 10/2=5. Most offsets are thermocouple effects caused by temperature gradients in the measurement circuitry or wiring.

Reversing the excitation polarity cancels voltage offsets in the sensor, wiring, and measurement circuitry. One measurement is made with the excitation voltage with the polarity programmed and a second measurement is made with the polarity reversed. The excitation "on time" for each polarity is exactly the same to ensure that ionic sensors do not polarize with repetitive measurements.

Reversing the inputs of a differential measurement cancels offsets in the CR5000 measurement circuitry and improves common-mode rejection. One measurement is made with the high input referenced to the low input and a second with the low referenced to the high.

3.1.3 Measuring Single-Ended Offset

The single-ended offset is a voltage offset on a single-ended input. It is measured by internally switching the input to ground and measuring the voltage. When a single-ended measurement is made this offset is corrected for in the calibration. The offset can either be measured automatically as part of the background calibration or as part of the measurement sequence each time the measurement is made (adding to the time to make the measurement). When the offset is measured in the measurement sequence, the offset is measured once prior to completing all of the instruction reps.

The MeasOfs parameter in instructions that make single-ended voltage measurements is used to force the offset measurement. In most cases the background calibration is adequate. Additional accuracy can be gained by making the offset measurement with each measurement instruction when the offset is changing rapidly as it would during when the CR5000 is undergoing rapid temperature swings.

3-2

3.1.4 SettlingTime

When the CR5000 switches to a new channel or switches on the excitation for a bridge measurement, there is a finite amount of time required for the signal to reach its true value. Delaying between setting up a measurement (switching to the channel, setting the excitation) and making the measurement allows the signal to settle to the correct value. The default settling times are the minimum required for the CR5000 to settle to within its accuracy specifications. Additional time is necessary when working with high sensor resistances or long lead lengths (higher capacitance). Using a longer settling time increases the time required for each measurement. Section 3.3 goes into more detail on determining an adequate settling time.

When the CR5000 Reverses the differential input or the excitation polarity it delays the same settling time after the reve r sal as it d oes before the first measurement. Thus there are two delays per channel when either RevDiff or RevEx is used. If both RevDiff and RevEx are selected, there are four measurement segments, positive and negative excitations with the inputs one way and positive and negative excitations with the inputs reversed. The CR5000 switches to the channel:

Section 3. CR5000 Measurement Details

sets the excitation, delays, measures, reverses the excitation, delays, measures, reverses the excitation, reverses the inputs, delays, measures, reverses the excitation, delays, measures.

3.1.5 Integration

Thus there are four delays per channel measured. The CR5000 processes the measurement segments into the single value it returns for the measurement.

Integration is used to reduce the noise included in a measurement. The CR5000 may use a combination of analog and digital integration.

For the fastest measurements, there is a zero integration measurement. This measurement does not integrate. The signal at a precise instant is sampled and this voltage is held for A/D conversion.

With analog integration, the input signal is integrated for a precise period of time. The integrated value is held for the A/D conversion. There are three possible analog integration times 20 ms, 16.67 ms and 250 µs. The 20 ms (1/50 second) and 16.667 ms (1/60 second) are available to integrate out the effects of noise from 50 or 60 Hz AC power sources.

An integration time in microseconds is specified as part of the measurement instruction. An integration time of 0 selects the sample-and-hold, 250 selects the 250 µs integration, 16667 or “_60 Hz” selects the 60 Hz rejection (16667 µs), and 20000 or “_50 Hz” selects 50 Hz rejection (20000 µs).

In addition to the analog integrations, it is possible to average a number of the sample-and-hold or 250 µs integration measurements. The A/D conversions are made as rapidly as possible: every 100 µs for the samples and every 500 µs for the 250 µs integrations. If the integration time specified is 250 µs or a

3-3

Section 3. CR5000 Measurement Details

multiple of 500 µs, the CR5000 will repeat 250 µs integration measurements every 500 µs throughout the integration interval. If the integration time specified is 100 µs or 200 µs, the CR5000 makes one or two samples in the integration interval. The average of these measurements is stored as the result of the measurement.

The random noise level is decreased by the square root of the number of measurements made. For example, the input noise on the ±5000 mV range with one 250 µs integration is 120 µV RMS; entering 2000 µs for the integration (four measurements) will cut this noise in half (120/(√4)=60).

The integration time specified in the measurement instruction is used for each segment of the measurement. Thus, if reversing the differential input or reversing the excitation is specified, th ere will be two integrations per channel; if both reversals are specified, there will b e four integrations.

3.2 Single Ended and Differential Voltage

Measurements

A single-ended voltage measurement is made on a single input which is measured relative to ground. A differential measurement measures the difference in voltage between two inputs.

NOTE

There are two sets of channel numbers on the analog channels. Differential channels (1-20) have two inputs: high (H) and low (L). Either the high or low side of a differential channel can be used for a single ended measurement. The single-ended channels are numbered 1-40.

Because a single ended measurement is referenced to CR5000 ground, any difference in ground potential between the sensor and the CR5000 will result in an error in the measurement. For example, if the measuring junction of a copper-constantan thermocouple, being used to measure soil temperature, is not insulated and the potential of earth ground is 1 mV greater at the sensor than at the point where the CR5000 is grounded, the measured voltage would be 1 mV greater than the thermocouple output, or approximately 25 Another instance where a ground potential difference creates a problem is where external signal conditioning circuitry is powered from the same source as the CR5000. Despite being tied to the same ground, differences in current drain and lead resistance result in different ground potential at the two instruments. For this reason, a differential measurement should be made on an analog output from the external signal conditioner. Differential measurements MUST be used when the inputs are known to be different from ground, such as the output from a full bridge.

Common mode range

C high.

3-4

In order to make a differential measurement, the inputs must be within the

5 V. The common mode range is the

CR5000 common mode range of voltage range, relative to CR5000 ground, within which both inputs of a differential measurement must lie, in order for the differential measurement to

Section 3. CR5000 Measurement Details

be made. For example, if the high side of a differential input is at 4 V and the low side is at 3 V relative to CR5000 ground, there is no problem. A

measurement made on the the high input is at 5.8 V and the low input is at 4.8 V, the measurement can not be made because the high input is outside of the range (the CR5000 will indicate the overrange by returning not-a-number (NAN)).

Sensors that have a floating output or are not referenced to ground through a separate connection may need to have one side of the differential input connected to ground to ensure the signal remains within the common mode range.

Problems with exceeding common mode range may be encountered when the CR5000 is used to read the output of external signal conditioning circuitry if a good ground connection does not exist between the external circuitry and the CR5000. When operating where AC power is available, it is not always safe to assume that a good ground connection exists through the AC wiring. If a CR5000 is used to measure the output from a laboratory instrument (both plugged into AC power and referencing ground to outlet ground), it is best to run a ground wire between the CR5000 and the external circuitry. Even with this ground connection, the ground potential of the two instruments may not be at exactly the same level, which is why a differential measurement is desired.

5000 mV range will return 1000 mV. However, if

5 V common mode

A differential measurement has the option of reversing the inputs to cancel offsets as described above.

NOTE

Sustained voltages in excess of ±16 V will damage the CR5000 circuitry.

3.3 Signal Settling Time

Whenever an analog input is switched into the CR5000 measurement circuitry prior to making a measurement, a finite amount of time is required for the signal to stabilize at it's correct value. The rate at which the signal settles is determined by the input settling time constant which is a function of both the source resistance and input capacitance.

The CR5000 delays after switching to a channel to allow the input to settle before initiating the measurement. The default delays used by the CR5000 depend on the integration used and the voltage range. For the sample-andhold, the default delay is 100 µs on the ±5000, ±1000, ±200, and ±50 mV ranges and 200 µs on the ±20 mV range. The default delay is 200 µs for 250 µs integrations and 3 ms for 50 Hz or 60 Hz rejection integrations. This settling time is the minimum required to allow the input to settle to the resolution specification.

Additional wire capacitance associated with long sensor leads can increase the settling time constant to the point that measurement errors may occur. There are three potential sources of error wh ich must settle before the measurement is made:

3-5

Section 3. CR5000 Measurement Details

1. The signal must rise to its correct valu e.

2. A small transient caused by switching the analog input into the measurement circuitry must settle.

3. When a resistive bridge measurement is made using a switched excitation channel, a larger transient caused when the excitation is switched must settle.

3.3.1 Minimizing Settl i ng Errors

When long lead lengths are mandatory, the following general practices can be used to minimize or measure settling error s:

1. DO NOT USE WIRE WITH PVC INSULATED CONDUCTORS. PVC has a high dielectric which extends input settling time.

2. Where possible run excitation leads and signal leads in separate shields to minimize transients.

3. When measurement speed is not a prime consideration, additional time can be used to ensure ample settling time. The settlin g time required can be measured with the CR5000.

3.3.2 Measuring the Necessary Settling Time

The CR5000 can measure the time required for a particular sensor/cable configuration to settle. This is done by allowing the signal to settle the minimum amount of time and then making zero integration measurements every 100 µs. Looking at the series of measurements it is possible to see the settling of the sensor signal. By counting the number of measurements before the signal settles the correct settling time can be determined (100 µs per measurement plus an extra 100 µs if the measurement is made on the 20 mV range where the default settling time is 200 µs).

NOTE

This technique for measuring settling time can only be u sed with instructions that measure only one voltage per repetition. The settling time to use with instructions that make more than one measurement can be determined with an instruction that uses only one measurement. For example, for the BrFull6W determine the settling time with BrFull; for BrHalf3W use BrHalf.

The following example demo nstrates measuring the settling time for a differential voltage measurement. If you are not yet familiar with CR5000 programming, you may want to read Section 4 before trying to follow the example.

3-6

The series of measurements on the sensor is made with one instruction. Measurement instructions have a repetitions parameter that allow one instruction to repeat the measurement on a number of channels. There is also the capability to repeat measurements on th e same channel. When

Section 3. CR5000 Measurement Details

measurements are repeated on the same ch annel the settling time is only necessary before the first measurement (as long as the excitation polarity and differential inputs are not reversed).

Before the program to measu re the settling time is run, the sensor with the cable that will be used in the installation needs to be connected and the sensor needs to be stabilized. If the sensed value is changing rapidly it will be difficult to separate the settling time from true changes in the value measured. The following program measures the settling time on a full bridge pressure transducer.

'CR5000 'Program to measure the settling time on a Pressure Transducer

'Declare the variable array for the 20 Pressure Transducer measurements:

public PT(20)

'Set up the output table for the measurement data:

DataTable (SetlDat,1,5) Sample (20,PT(),IEEE4) EndTable

'The following program repeats the 20 measurements 5 times:

BeginProg Scan (1,Sec,3,5) 'The -1 in the differential channel parameter of BrFull tells 'the CR5000 to make the 20 measurements on channel 1: BrFull (PT(),20,mV50,-1,Vx1,20,5000,False,False,0,0,1.0,0) CallTable SetlDat NextScan EndProg

The program was run on a Druck water level pressure transducer with 200 feet of cable. The first six measurements of each of the 5 readings are shown in Table 3.3-1. The reading has settled by the second measurement, PT(2), thus a settling time of 200 µs is adequate.

Table 3.3-1. First Six Values of Settling Time Data

PT(1) PT(2) PT(3) PT(4) PT(5) PT(6)

0.291257 0.052925 0.053937 0.054274 0.057645 0.056296

0.292269 0.052925 0.053262 0.054948 0.055622 0.056633

0.286538 0.053937 0.054274 0.055959 0.053599 0.054948

0.284515 0.052925 0.052925 0.053599 0.057645 0.055285

0.286875 0.052925 0.052925 0.054611 0.056296 0.057308

3.4 Thermocouple Measurements

A thermocouple consists of two wires, each of a different metal or alloy, which are joined together at each end. If the two junctions are at different temperatures, a voltage proportional to the difference in temperatures is induced in the wires. If the junctions are at the same temperature, there is no voltage. When a thermocouple is used for temperature measurement, the wires are soldered or welded together at the measuring junction. The second

3-7

Section 3. CR5000 Measurement Details

junction, which becomes the reference junction, is formed where the other ends of the wires are connected to the measuring device. (With the connectors at the same temperature, the chemical dissimilarity between the thermocouple wire and the connector does not induce any voltage.) When the temperature of the reference junction is known, the temperature of the measuring junction can be determined by measuring the thermocouple voltage and adding the corresponding temperature difference to the reference temperature.

The CR5000 determines thermocouple temperatures using the following sequence. First the temperature of the reference junction is measured and stored in °C. If the reference junction is the CR5000 analog input terminals, the temperature is measured with the bu ilt in thermistor (PanelTemp instruction). The thermocouple measurement instruction measures the thermocouple voltage (TCDiff or TCSE). The thermocouple instruction calculates the voltage that a thermocouple of the type specified would output at the reference junction temperature if its reference junction were at 0 adds this voltage to the thermocouple voltage. The temperature of the measuring junction is then calculated from a polynomial approximation of the NIST TC calibrations

3.4.1 Error Analysis

C, and

Panel Temperature

The error in the measurement of a thermocouple temperature is the sum of the errors in the reference junction temperature, the thermocouple output (deviation from standards published in NIST Monograph 175), the thermocouple voltage measurement, and the linearization error (difference between NIST standard and CR5000 polynomial approximations). The discussion of errors which fo llows is limited to these errors in calibration and measurement and does not include errors in installation or matching the sensor to the environment being measured.

A brass bar is just under the CR5000 panel between the two rows of analog input terminals. This bar helps to reduce temperature gradients between the terminals. The panel temperature thermistor is in a depression in the center of this bar.

The thermistor (Betatherm 10K3A1A) has an interchangability specification of

0.1 °C for temperatures between 0 and 70 °C. Below freezing and at higher

temperatures this specification is degraded (Figure 3.4.1). Combined with possible errors in completion resistors and the measurement, the accuracy of panel temperature is ±0.25 °C 0 to 40 °C, ±0.5 °C -25 to 50 °C, and ±0.7 °C

-40 to 85 °C.

3-8

Section 3. CR5000 Measurement Details

0.3

0.25

0.2

0.15

Thermistor Tolerance ºC

0.1

0.05

-60-50-40-30-20-100 102030405060708090100

Temperature ºC

FIGURE 3.4-1. Thermistor Tolerance

The error in the reference temperature measurement is a combination of the error in the thermistor temperature and the difference in temperature between the panel thermistor and the terminals the thermocouple is connected to. The terminal strip cover should always be used when making thermocouple measurements. It insulates the terminals from drafts and rapid fluctuations in temperature as well as conducting heat to reduce temperature gradients. In a typical installation where the CR5000 is in a weather proof enclosure not subject to violent swings in temperature or lopsided solar radiation loading, the temperature difference between the terminals and the thermistor is likely to be less than 0.2 °C.

With an external driving gradient, the temperature gradients on the input panel can be much worse. For example, the CR5000 with the rechargeable battery back was placed in a controlled temperature chamber. Thermocouples in channels at the ends and middle of each analog terminal strip measured the temperature of an insulated aluminum bar outside the chamber. The temperature of this bar was also measured by another datalogger. Differences between the temperature measured by one of the thermocouples and the actual temperature of the bar are due to the temperature difference between the terminals the thermocouple is connected to and the thermistor reference (the figures have been corrected for thermistor errors). Figure 3.4-2 shows the errors when the chamber was changed from -55 to 80 °C in approximately 15 minutes. Figure 3.4-3 shows the results when going from 80 to 25 °C in approximately 45 minutes, a less dramatic change but still greater than would be seen in most natural circumstances. During these rapid changes in temperature, the temperature of panel thermistor will tend to lag behind the terminals because it is buried a bit deeper in the CR5000 and is closer to the

3-9

Section 3. CR5000 Measurement Details

thermal mass of the batteries. Note that the smallest errors are on channels 5 and 16 in the middle of th e ter minal strips closest to the thermistor.

Reference Temperature Errors Due to Panel Gradient Chamber changed from -55 to 80 °C at maximum rate

-1

-2

-3

Measured - Actual (°C)

-4

-5

-6

-7 0

-5

Chanel 1 Chanel 5 Chanel 10 Chanel 11 Chanel 16 Chanel 20 Panel Chamber

Time (minu te s )

-20

-40

-60

FIGURE 4.3-2. Panel Temperature Gradients During -55 to 80 °C change

Chamber and CR5000 Panel Temperature (°C)

3-10

Section 3. CR5000 Measurement Details

Reference Temperatu re Errors Due to Panel Gradient

Chamber Changed From 80 to 25 °C at 1.3 °C/M inu te

1.4

1.2

0.8

0.6

0.4

Measured - Actual (°C)

0.2

-0.2

-0.4 0

-5

FIGURE 4.3-3. Panel Temperature Gradients During 80 to 25 °C change

Thermocouple Limits of Error

Time (minutes)

Channel 1 Channel 5 Channel 10 Channel 11 Channel 16 Channel 20 Panel Chamber

Chamber and CR5000 Panel Temperature (°C)

The standard reference which lists thermocouple output voltage as a function

of temperature (reference junction at 0

C) is the National Institute of Standa r ds and Technology Monograph 175 (1993). The American National Standards Institute has established limits of error on thermocouple wire which is accepted as an industry standard (ANSI MC 96.1, 1975). Table 3.4-1 gives the ANSI limits of error for standard and special grade thermocouple wire of the types accommodated by the CR5000.

TABLE 3.4-1. Limits of Error for Thermocouple Wire (Reference Junction at 0

Limits of Error

Thermocouple Temperature (Whichever is greater)

Type Range oC Standard Special

T -200 to 0

0 to 350

J 0 to 750

E -200 to 0

0 to 900

K -200 to 0

0 to 1250

R or S 0 to 1450

B 800 to 1700

1.0oC or 1.5%

1.0oC or 0.75%

2.2oC or 0.75%

1.7oC or 1.0%

1.7oC or 0.5%

2.2oC or 2.0%

2.2oC or 0.75%

1.5oC or 0.25%

0.5% Not Estab.

0.5oC or 0.4%

1.1oC or 0.4%

1.0oC or 0.4%

1.1oC or 0.4%

0.6oC or 0.1%

3-11

Section 3. CR5000 Measurement Details

When both junctions of a thermocouple are at the same temperature there is no voltage produced (law of interm ed iate metals). A consequence of this is that a thermocouple can not have an offset error; any deviation from a standard (assuming the wires are each homogeneous and no secondary junctions exist) is due to a deviation in slope. In light of this, the fixed temperature limits of error

1.0 °C for type T as opposed to the slope error of 0.75% of the temperature)

(e.g., in the table above are probably greater than one would experience when considering temperatures in the environmental range (i.e., the reference junction, at 0 °C, is relatively close to the temperature being measured, so the absolute error the product of the temperature difference and the slope error - should be closer to the percentage error than the fixed error). Likewise, because thermocouple calibration error is a slope error, accuracy can be increased when the reference junction temperature is close to the measurement temperature. For the same reason differential temperature measurements, over a small temperature gradient, can be extremely accurate.

In order to quantitatively evaluate thermocouple error when the reference

junction is not fixed at 0

C, one needs limits of error for the Seebeck coefficient (slope of thermocouple voltage vs. temperature curve) for the various thermocouples. Lacking this information, a reasonable approach is to apply the percentage errors, with perhaps 0.25% added on, to the difference in temperature being measured by the thermocouple.

Accuracy of the Thermocouple Voltage Measurement

The -25 to 50 °C accuracy of a CR5000 differential voltage measurement is specified as ± (0.075% of the measured voltage plus the input offset error of 2 times the basic resolution of the range being used to make the measurement plus 2 µV). The input offset error reduces to the basic resolution if the differential measurement is made utilizin g the option to reverse the differential input.

For optimum resolution, the ±20 mV range is used for all but high temperature measurements (Table 3.4-2). The input offset error dominates the voltage measurement error for environmental measurements. A temperature difference of 45 to 65 °C between the measurement and reference junctions is required for a thermocouple to output 2.67 mV, the voltage at which 0.075% of the reading is equal to 2 µV. For example, assume that a type T thermocouple is used to measure a temperature of 45 °C and that the reference temperature is 25 °C. The voltage output by the thermocouple is 830.7 µV. At 45 degrees a type T thermocouple outputs 42.4 µV per measurement is 0.00075x830.7 µV = 0.62 µV or 0.014 basic resolution on the ±20 mV range is 0.67 µV or 0.01

is an error of 0.047 measurement is 0.081

C. Thus, the possible error due to the voltage

C on a non-reversing differential, or 0.024 oC with a reversing differential measurement. The value of using a differential measurement with reversing input to improve accuracy is readily apparent.

C. The possible slope error in the voltage

C (0.62/42.4). The

C. The 2 µV offset

3-12

The error in the temperature due to inaccuracy in the measurement of the thermocouple voltage is worst at temperature extremes, particularly when the temperature and thermocouple type require using the 200 mV range. For example, assume type K (chromel-alumel) thermocouples are used to measure

temperatures around 1300

C. The TC output is on the order of 52 mV,

Section 3. CR5000 Measurement Details

requiring the ±200 mV input range. At 1300

34.9 µV per

0.00075x52 mV = 39 µV or 1.12 mV range is 6.67 µV or 0.19 measurement is 1.56

C. The possible slope error in the voltage measurement is

C (39/34.9). The basic resolution on the 200

C on a non-reversing differential, or 1.31 oC with a

C. Thus, the possible error due to the voltage

C, a K thermocouple outputs

reversing differential measurement.

TABLE 3.4-2. Voltage Range for maximum Thermocouple reso l ution

TC Type and temp.

range

Temp. range for ±20 mV range

Temp. range for ±50 mV range

Temp. range for ±200 mV range

T -270 to 400 -270 to 400 not used not used E -270 to 1000 -270 to 280 -270 to 660 >660 K --270 to 1372 -270 to 610 -270 to 1230 >1230 J -210 to 1200 -210 to 360 -210 to 870 > 870 B 0 to 1820 0 to 1820 not used not used R -50 to 1768 -50 to 1680 -50 to 1768 not used S -50 to 1768 -50 to 1768 not used not used N -270 to 1300 -270 to 580 -270 to 1300 not used

When the thermocouple measurement junction is in electrical contact with the object being measured (or has the possibility of making contact) a differential measurement should be made.

Noise on Voltage Measurement

The typical input noise on the ±20 mV range for a differential measurement with no integration and input reversal is 1.8 µV RMS. On a type T

thermocouple (approximately 40 µV/

C) this is 0.05 oC. Note that this is an RMS value, some individual read ings will vary by greater than this. By integrating for 250 µs the noise level is reduced to 0.6 µV RMS.

Thermocouple Polynomial: Voltage to Temperature

NIST Monograph 175 gives high order polynomials for computing the output voltage of a given thermocouple type over a broad range of temperatures. In order to speed processing and accommodate the CR5000's math and storage capabilities, 4 separate 6th order polynomials are used to convert from volts to temperature over the range covered by each thermocouple type. Table 3.4-3 gives error limits for the thermocouple polynomials.

3-13

Section 3. CR5000 Measurement Details

TABLE 3.4-3. Limits o f Error on CR5000 Thermocouple Polynomials

Type Range oC Limits of Error oC

T -270 to 400

(Relative to NIST Standards)

-270 to -200

-200 to -100

-100 to 100 100 to 400

18 @ -270

0.08

0.001

0.015

J -150 to 760

-100 to 300

± ±

0.008

0.002

E -240 to 1000

-240 to -130

-130 to 200 200 to 1000

± ± ±

0.4

0.005

0.02

K -50 to 1372

-50 to 950 950 to 1372

± ±

0.01

0.04

Reference Junction Compensation: Temperature to Voltage

The polynomials used for reference junction compensation (converting reference temperature to equivalent TC output voltage) do not cover the entire thermocouple range. Substantial errors will result if the reference junction temperature is outside of the linearization range. The ranges covered by these linearizations include the CR5000 environmental operating range, so there is no problem when the CR5000 is used as the reference junction. External reference junction boxes however, must also be within these temperature ranges. Temperature difference measurements made outside of the reference temperature range should be made by obtaining the actual temperatures referenced to a junction within the reference temperature range and subtracting one temperature from the other. Table 3.4-3 gives the reference temperature ranges covered and the lim its of error in the linearizations within these ranges.

3-14

Two sources of error arise when the reference temperature is out of range. The most significant error is in the calculated compensation voltage, however error is also created in the temperature difference calculated from the thermocouple output. For example, suppose the reference temperature for a measurement on

a type T thermocouple is 300 CR5000 corresponds to a temperature of 272.6 T thermocouple with the measuring junction at 290

would output -578.7

V; using the reference temperature of 272.6

CR5000 calculates a temperature difference of -10.2 temperature calculated by the CR5000 would be 262.4

C. The compensation voltage calculated by the

C, a -27.4

C error. The type

C and reference at 300

C, a -0.2

C, 27.6

C, the

C error. Th e

C low.

Section 3. CR5000 Measurement Details

TABLE 3.4-4. Reference Temperature Compensation Range and

Polynomial Error Relative to NIST St andards

Type Range oC Limits of Error oC

Error Summary

T -100 to 100

0.001

J -150 to 296 ± 0.005

E -150 to 206 ± 0.005

K -50 to 100 ± 0.01

The magnitude of the errors descr ib ed in the previous sections illustrate that the greatest sources of error in a thermocouple temperature measurement with the CR5000 are likely to be due to the limits of error on the thermocouple wire and in the reference temperature. Errors in the thermocouple and reference temperature linearizations are extremely small, and error in the voltage measurement is negligible.

To illustrate the relative magnitude of these errors in the environmental range, we will take a worst case situation where all errors are maximu m and additive.

A temperature of 45 thermocouple, using the 1 µV (0.01% of 10 mV) which at 45

The RTD is 25 thermocouple is connected to is 0.05

C is measured with a type T (copper-constantan)

20 mV range. The nominal accuracy on this range is

C but is indicating 25.1

C changes the temperature by 0.012

C, and the terminal that the

C cooler than the RTD.

TABLE 3.4-5. Example of Errors in Thermocouple Temperature

Source Error: oC : % of Total Error

Single Differential

No Integration ANSI TC Error (1oC)

TC Error 1% Slope

Reversing Differential

250 µs Integration ANSI TC Error (1oC)

TC Error 1%

Slope Reference Temp. 0.15o:11.5% 0.15o:29.8% 0.15o:12.6% 0.15o:38.4% TC Output 1.0o:76.7% 0.2o:39.8% 1.0o:84% 0.2o:51.2%

Voltage

0.081

:6.2% 0.081o:16.1% 0.024o:2% 0.024o:6.1% Measurement Noise 0.07o:5.4% 0.07o:13.9% 0.015o:1.2% 0.015o:3.8%

Reference

0.001

:0.1% 0.001o:0.2% 0.001o:0.1% 0.001o:0.25% Linearization

Output

0.001

:0.1% 0.001o:0.2% 0.001o:0.1% 0.001o:0.25% Linearization Total Error 1.303o:100% 0.503o:100% 1.191o:100% 0.391o:100%

3.4.2 Use of External Reference Junction or Junction Box

An external junction box is often used to facilitate connections and to reduce the expense of thermocouple wire when the temperature measurements are to be made at a distance from the CR5000. In most situations it is preferable to make the box the reference junction in which case its temperature is measured and used as the reference for the thermocouples and copper wires are run from

3-15

Section 3. CR5000 Measurement Details

the box to the CR5000. Alternatively, the junction box can be used to couple extension grade thermocouple wire to the thermocouples, and the CR5000 panel temperature used as the reference. Extension grade thermocouple wire has a smaller temperature range than standard thermocouple wire, but meets the same limits of error within that ran g e . Th e only situation where it would be necessary to use extension grade wire instead of a external measuring junction is where the junction box temperature is outside the range of reference junction compensation provided by the CR5000. This is only a factor when using type K thermocouples, where the upper limit of the reference compensation linearization is 100

C. With the other types of thermocouples the reference compensation range equals or is greater than the extension wire range. In any case, errors can arise if temperature gradients exist within the junction box.

Figure 3.4-1 illustrates a typical junction box. Terminal strips will be a different metal than the thermocouple wire. Thus, if a temperature gradient exists between A and A' or B and B', the junction box will act as another thermocouple in series, creating an error in the voltage measured by the CR5000. This thermoelectric offset voltage is a factor whether or not the junction box is used for the reference. This offset can be minimized by making the thermal conduction between the two points large and the distance small. The best solution in the case where extension grade wire is being connected to thermocouple wire would be to use connectors which clamped the two wires in contact with each other.

C and the upper limit of the extension grade wire is 200

CR9000

CR5000 Junction Box

Junction Box

A' A

B' B

FIGURE 3.4-1. Diagram of Junction Box

An external reference junction box must be constructed so that the entire terminal area is very close to the same temperature. This is necessary so that a valid reference temperature can be measured and to avoid a thermoelectric offset voltage which will be induced if the terminals at which the thermocouple leads are connected (points A and B in Figure 3.4-1) are at different temperatures. The box should contain elements of high thermal conductivity, which will act to rapidly equilibrate any thermal gradients to which the box is subjected. It is not necessary to design a constant temperature box, it is desirable that the box respond slowly to external temperature fluctuations.

Radiation shielding must be provided when a junction box is installed in the field. Care must also be taken that a thermal gradient is not induced by conduction through the incoming wires. The CR5000 can be used to measure the temperature gradients within the junction box.

3-16

Section 3. CR5000 Measurement Details

3.5 Bridge Resistance Measurements

There are six bridge measurement instructions included in the standard CR5000 software. Figure 3.5-1 shows the circuits that would typically be measured with these instructions. In the diagrams, the resistors labeled R would normally be the sensors and those labeled Rf would normally be fixed resistors. Circuits other than those diagrammed could be measured, provided the excitation and type of measurements were appropriate.

All of the bridge measurements have the option (RevEx) to make one set of measurements with the excitation as programmed and another set of measurements with the excitation polarity reversed. The offset error in the two measurements due to thermal emfs can then be accounted for in the processing of the measurement instruction. The excitation channel maintains the excitation voltage or current until the hold for the analog to digital conversion is completed. When more than one measurement per sensor is necessary (four wire half bridge, three wire half bridge, six wire full bridge), excitation is applied separately for each measurement. For example, in the four wire half bridge when the excitation is reversed, the differential measurement of the voltage drop across the sensor is made with the excitation at both polarities and then excitation is again applied and reversed for the measurement of the voltage drop across the fixed resistor.

BrHalf

BrHalf3W

Calculating the actual resistance of a sensor which is one of the legs of a resistive bridge usually requires additional processing following the bridge measurement instruction. In addition to the schematics of the typical bridge configurations, Figure 3.5-1 lists the calculations necessary to compute the resistance of any single resistor, provided the values of the other resistors in the bridge circuit are known.

X = result w/mult = 1, offset = 0

VRRR

xssf

X = result w/mult = 1, offset = 0

−

VVRR

−

RRX

−

()

3-17

Section 3. CR5000 Measurement Details





BrHalf4W

BrFull

BrFull6W

X = result w/mult = 1, offset = 0

VVR

X = result w/mult = 1, offset = 0

X 1000

 



R3R



1000

−

R1R

X = result w/mult = 1, offset = 0

1000 1000



RRRRR



−

34212

 







 

RRX

XX RRR

=− + +

1000

1334

−

()

−

=++

1000

2212

−

()

Resistance

IXR

Resistance

used to measure full bridge

IXR

FIGURE 3.5-1. Circuits Used with Bridge Measurement Instructions

X = result w/mult = 1, offset = 0

RR R RR R

31 2 23 4

()()





bridge

RRRRR



34212

+− +

+++

RRRR

1234

− +

−− ++

RR X R R R

24 2 3 4

  

RR X R R R

13 1 3 4

−−++

RR X R R R

24 1 2 4

RR X R R R

13 1 2 3

()

−

−++

()

−

−++

()

3-18

Section 3. CR5000 Measurement Details

3.6 Measurements Requiring AC Excitation

Some resistive sensors require AC excitation. These include electrolytic tilt sensors, soil moisture blocks, water conductivity sensors and wetness sensing grids. The use of DC excitation with these sensors can result in polarization, which will cause an erroneous measuremen t, and may shift the calibration of the sensor and/or lead to its rapid decay.

Other sensors like LVDTs (without built in electronics) require an AC excitation because they rely on inductive coupling to provide a signal. DC excitation would provide no output.

Any of the bridge measurements can reverse excitation polarity to provide AC excitation and avoid ion polarization. The frequency of the excitation can be determined by the delay and integ r ation time used with the measurement. The highest frequency possible is 5 kHz, the excitation is switched on and then reversed 100 µs later when the first measurement is held and then is switched off after another 100 µs when the second measurement is held (i.e., reverse the excitation, 100 µs delay, no integration).

Influence of Ground Loop on Measurements

When measuring soil moisture blocks or water conductivity the potential exists for a ground loop which can adversely affect the measurement. This ground loop arises because the soil and water provide an alternate path for the excitation to return to CR5000 ground, and can be represented by the model diagrammed in Figure 3.6-1.

FIGURE 3.6-1. Model of Resistive Sensor with Ground Loop

In Figure 3.6-1, V sensor resistance, and R CR5000 earth ground. With R

is the excitation voltage, Rf is a fixed resistor, Rs is the

is the resistance between the excited electrode and

in the network, the measured signal is:

()

RRRRR

sf sfG

[3.6-1]

R equation reduces to the ideal. The geometry of the electrodes has a great effect on the magnitude of this error. The Delmhorst gypsum block used in the 227 probe has two concentric cylindrical electrodes. The center electrode is used

is the source of error due to the ground loop. When RG is large the

sRf/RG

3-19

Section 3. CR5000 Measurement Details

for excitation; because it is encircled by the ground electrode, the path for a ground loop through the soil is greatly reduced. Moisture blocks which consist of two parallel plate electrodes are particularly susceptible to ground loop problems. Similar considerations apply to the geometry of the electrodes in water conductivity sensors.

The ground electrode of the conductivity or soil moisture probe and the CR5000 earth ground form a galvanic cell, with the water/soil solution acting as the electrolyte. If current was allowed to f low, the resulting oxidation or reduction would soon damage the electrode, just as if DC excitation was used to make the measurement. Campb ell Scientific probes are built with series capacitors in the leads to block this DC curren t. I n addition to preventing sensor deterioration, the capacitors block any DC component from affecting the measurement.

3.7 Pulse Count Measurements

Many pulse output type sensors (e.g., anemometers and flow-meters) are calibrated in terms of frequency (counts/second). For these measurements the accuracy is related directly to the accuracy of the time interval over which the pulses are accumulated. Frequency dependent measurements should have the PulseCount instruction programmed to return frequency. If the number of counts is primary interest, PulseCount should be programmed to return counts (i.e., the number of times a door opens, the number of tips of a tipping bucket rain gage).

The interval of the scan loop that PulseCount is in is not the sole determining factor in the calculation of frequency. While normally the counters will be read on the scan interval, if execution is delayed, for example by lengthy output processing, the pulse counters are not read until the scan is synchronized with real time and restarted. The CR5000 actually measures the elapsed time since the last time the counters were read when determining frequency so in the case of an overrun, the correct frequency will still be output.

The resolution of the pulse counters is one count. The resolution of the calculated frequency depends on the scan interval: frequency resolution = 1/scan interval (e.g., a pulse count in a 1 second scan has a frequency resolution of 1 Hz, a 0.5 second scan gives a resolution of 2 Hz, and a 1 ms scan gives a resolution of 1000 Hz). The resultant measurement will bounce around by the resolution. For example, if you are scanning a 2.5 Hz input once a second, in some intervals there will be 2 counts and in some 3 as shown in figure 3.7-1. If the pulse measur em ent is averaged, the correct value will be the result.

3 2 3 2

3-20

FIGURE 3.7-1. Varying counts within Pulse interval.

The resolution gets much wo r se with the shorter intervals used with higher speed measurements. As an example, assume that engine RPM is being measured from a signal that outputs 30 pulses per revolution. At 2000 RPM, the signal has a frequency of 100 Hz (2000 RPMx(1 min/60 s)x30=1000). The multiplier to convert from frequency to RPM is 2 RPM/Hz (1 RPM/(30 pulses/60s) = 2). At a 1 second scan interval, the resolution is 2 RPM. However, if the scan interval were 1 ms, the resolution would be 2000 RPM. At the 1 ms scan, if every thing was perfect, each interval there would be 1 count. However, a slight variation in the frequency might cause 2 counts within one interval and none in the next, causing the result to vary between 0 and 4000 RPM!

3.8 Self Calibration

The CR5000 performs a self-calibration of the analog voltage measurements and excitation voltages. The range gains and offsets and the excitation voltage output will vary with temperature. The self calibration allows the CR5000 to maintain its specifications over the temp erature range.

Rather than make all of the measurements required to calibrate all range/integration type combinations possible in the CR5000, the calibration only measures the range/integration type combinations that occur in the running CR5000 program. The calibration may occur in three different modes.

Section 3. CR5000 Measurement Details

1. Compile time calibration. This occurs prior to running the program and calibrates all integration/range combinations needed. For the 250 usc and zero integrations multiple measurements are m ade and averaged to come up with gain values to use in the measurements. Ten measurements are made on the zero integration ranges and five measurements for the 250 usec integrations. When this calibration is performed the values in the calibration table are completely replaced (i.e., no filtering is used).

2. System background calibration. This automatically takes place in the background while the user program is running. Multiple measurements are not averaged, but a filter is applied to th e new gain/offset values obtained. The filter is used so that the calibration values change slowly. The filter combines the newly measu r ed value multiplied by 0.1 with the previous calibration value by 0.9 to arrive at the new calibration value. A piece of the background calibration is added to each fast scan in the user program. The background calibration measurements will be repeated every 4 seconds or the time it takes to complete them, whichever is longer. If there is not enough time to do the background calibration, the CR5000 will display: “Warning when Fast Scan X is running background calibration will be disabled.” (X is the number of the fast scan where the first scan entered in the program is 1, the next scan is 2, etc.)

3. Calibration under program control. When the calibrate instruction is included in a program, the calibr ation is identical to the compile time calibration. The calibration table values are replaced with those calculated. The fast integrations have averaging as in the compile calibrate. When a calibrate instruction is found in any scan the

3-21

Section 3. CR5000 Measurement Details

background calibration will be disabled (even if the scan is not executed). The calibrate instruction is described in Section 7.

The self calibration does not take place if there is not enough time to run it or if the calibrate instruction is in the CR5000 program and never executed. Without the self calibration the drift in accuracy with temperature is about a factor of 10 worse. For example, over the extended temperature range (-40 to 85°C) the accuracy specification is approximately 0.1% of reading. If the self calibration is disabled, the accuracy over the range is approximately 1% of reading. Temperature is the main factor causing a calibration shift and the need for the self calibration. If the temperature of the CR5000 remains the same there will be little calibration drift with the self calibration disabled.

The time constant for the background calibration (at the 4 second rate) is approximately 36 seconds. This allows the CR5000 to remain calibrated during fairly rapid temperature changes. In cases of extreme temperature change, such as bringing a vehicle fr o m equilibrium in a chamber at -30°C out into a hot Arizona day, it may be worthwhile to override the background calibration by running the calibration instruction in the scan with the measurements.

Another case where using the calibration instruction makes sense is where there is not time for the background calibration in the normal scan but the program can periodically stop making measurements and run the calibration instruction in a separate scan.

3-22

Section 4. CRBasic - Native Language Programming

The CR5000 is programmed in a language that has some similarities to a structured basic. There are special instructions for making measurements and for creating tables of output data. The results of all measurements are assigned variables (given names). Mathematical operations are written out much as they would be algebraically. This section describes a program, its syntax, structure, and sequence.

4.1 Format Introduction

4.1.1 Mathematical Operations

Mathematical operations are written out much as th ey would be algebraically. For example, to convert a temperature in Celsius to Fahrenheit one might write:

TempF = TempC * 1.8 + 32

With the CR5000 there may be 2 or 20 temperature (or other) measurements. Rather than have 20 different names, a elements may be used. A thermocouple temperature might be called TCTemp. With an array of 20 elements the names of the individual temperatures are TCTemp(1), TCTemp(2), TCTemp(3), ... TCTemp(20). The array notation allows compact code to perform operations on all the variables. For example, to convert ten temperatures in a variable array from C to F:

variable array

with one name and 20

For I=1 to 10

TCTemp(I)=TCTemp(I)*1.8+32

Next I

4.1.2 Measurement and Output Processing Instructions

Measurement instructions are procedures that set up the measurement hardware to make a measurement and place the results in a variable or a variable array. Output processing instructions are procedures that store the results of measurements or calculated values. Output processing includes averaging, saving maximum or minimum, standard deviation, FFT, etc.

The instructions for making measurements and outputting data are not found in a standard basic language. The instructions Campbell Scientific has created for these operations are in the form of procedures. The procedure has a keyword name and a series of parameters that contain the information needed to complete the procedure. For example, the instruction for measuring the temperature of the CR5000 input panel is:

PanelTemp

(Dest, Integ)

4-1

Section 4. CRBasic - Native Language Programming

PanelTemp is the keyword name of the instruction. The two parameters associated with PanelTemp are: to put the temperature; and measurement. To place the panel temperature in the variable RefTemp (using a 250 microsecond measurement integration time) the code is:

PanelTemp(RefTemp, 250)

The use of these instructions should become clearer as we go through an introductory example.

4.1.3 Inserting Comments Into Program

Comments can be inserted into a program by preceding the comment with a single quote ('). Comments can be entered either as independent lines or following CR5000 code. When the CR5000 compiler sees the ' it ignores the rest of the line.

' The declaration of variables starts here. Public Start(6) 'Declare the start time array

ination, the name of the variable in wh ich

Dest

ration, the length of time to integrate the

Integ

4.2 Programming Sequence

The following table describes the structure of a typical CR5000 program:

Declarations

Declare constants Declare Public variables

Dimension variables

Define Aliases Define data tables.

Process/store trigger

Table size Other on-line storage

devices

Make a list of what to measure and calculate. Within this list, include the fixed constants used, indicate the values that the user is able to view

while the program is running,

the number of each measurement that will be

made, and specific names for any of the measurements. Describe, in detail, tables of data th at will be

saved from the experiment. Set when the data should be stored. Are they

stored when some condition is met? Are data

stored on a fixed interval? Are they stored on

a fixed interval only while some condition is

met? Set the size of the table in CR5000 RAM Should the data also be sent to the PC card?

4-2

Processing of Data

What data are to be output (current value,

average, maximum, minimum, etc.)

Section 4. CRBasic - Native Language Programming

Define Subroutines

Program

Set scan interval

Measurements Processing

Call Data Table(s)

Initiate controls

NextScan

End Program

If there is a process or series of calculations

that need to be repeated several times in the program, it can be packaged in a subroutine and called when needed rather than repeating all the code each time.

The program section defines the action of

datalogging

The scan sets the interval for a series of

measurements Enter the measurements to make Enter any additional processing with the

measurements The Data Table must be called to process output

data Check measurements and Initiate controls if

necessary Loop back (and wait if necessary) for the next

scan

4-3

Section 4. CRBasic - Native Language Programming

4.3 Example Program

Const RevDiff=1 Const Del=0 Const Integ=250 Const Mult=1 Const Offset=0

'default

Declare constants

Public RefTemp Public TC(6) Units RefTemp=degC Units TC=DegC

Declare public variables , dimension array, and declare units.

DataTable (Temp,1,2000)

DataInterval (0,100,mSec,10) Average (1,RefTemp,FP2,0)

Define Data Table

Average (6,TC(),FP2,0)

EndTable

BeginProg

Scan (10,mSec,3,0) PanelTemp (RefTemp, 250) TCDiff (TC(),6,mV20C ,1,TypeT,RefTemp,RevDiff,Del,Integ,Mult,Offset) CallTable Temp

Call Data Table

NextScan

EndProg

4.3.1 Data Tables

Data storage follows a fixed structure in the CR5000 in order to optimize the time and space required. Data are stored in tables such as:

Declarations

Measure

Scan loop

TOA4 StnName Temp TIMESTAMP RECORD RefTemp_Avg TC_Avg(1) TC_Avg(2) TC_Avg(3) TC_Avg(4) TC_Avg(5) TC_Avg(6) TS RN degC degC degC degC degC degC degC

Avg Avg Avg Avg Avg Avg Avg 1995-02-16 15:15:04.61 278822 31.08 24.23 25.12 26.8 24.14 24.47 23.76 1995-02-16 15:15:04.62 278823 31.07 24.23 25.13 26.82 24.15 24.45 23.8 1995-02-16 15:15:04.63 278824 31.07 24.2 25.09 26.8 24.11 24.45 23.75 1995-02-16 15:15:04.64 278825 31.07 24.21 25.1 26.77 24.13 24.39 23.76

The user's program determines the values that are output and their sequence. The CR5000 automatically assigns names to each field in the data table. In the above table, TIMESTAMP, RECORD, RefTemp_Avg, and TC_Avg(1) are fieldnames. The fieldnames are a combination of the variable name (or alias if one exists) and a three letter mnemonic for the processing instruction that outputs the data. Alternatively, the FieldNames instruction can be used to override the default names.

The data table header also has a row that lists units for the output values. The units must be declared for the CR5000 to fill this row out (e.g., Units RefTemp

4-4

Section 4. CRBasic - Native Language Programming

= degC). The units are strictly for the user's documentation; the CR5000 makes no checks on their accuracy.

The above table is the result of the data table description in the example program:

DataTable (Temp,1,2000)

DataInterval(0,10,msec,10) Average(1,RefTemp,fp2,0) Average(6,TC(1),fp2,0)

EndTable

All data table descriptions begin with DataTable and end with EndTable. Within the description are instructions that tell what to output and that can modify the conditions under which output occurs.

DataTable( DataTable (Temp,1,2000)

DataInterval( DataInterval(0,10,msec,10)

Name, Trigger, Size

The DataTable instruction has three parameters: a user specified name for the table, a trigger condition, and the size to make the table in CR5000 RAM. The trigger condition may be a variable, expression, or constant. The trigger is true if it is not equal to 0. Data are output if the tr igger is true and there are no other conditions to be met. No output occurs if the trigger is false (=0). The example creates a table name Temp, outputs any time other conditions are met, and retains 2000 records in RAM.

TintoInt, Interval, Units, Lapses

DataInterval is an instruction that modifies the conditions under which data are stored. The four parameters are the time into the interval, the interval on which data are stored, the units for time, and the number of lapses or gaps in the interval to keep track of. The example outputs at 0 time into (on) the interval relative to real time, the interval is 10 milliseconds, and the table will keep track of 10 lapses. The DataInterval instruction reduces the memory required for the data table because the time of each record can be calculated from the interval and the time of the most recent record stored. Other output condition modifiers are: Worst Case and FillandStop.

The output processing instructions included in a data table declaration determine the values output in the table. The table must be called by the program in order for the output processing to take place. That is, each time a new measurement is made, the data table is called. When the table is called, the output processing instructions within the table process the current inputs. If the trigger conditions for the are true, the processed values are output to the data table. In the example, several averages are output.

)

4-5

Section 4. CRBasic - Native Language Programming

Average( Average(1,RefTemp,fp2,0) Average(6,TC(1),fp2,0)

Code Data Format Size Range Resolution

FP2 Campbell Scientific floating point 2 bytes IEEE4 IEEE four byte floating point 4 bytes 1.8 E -38 to 1.7 E 38 24 bits (about 7 digits) LONG 4 byte Signed Integer 4 bytes -2,147,483,648 to

Reps, Source, DataType, DisableVar

Average is an output processing instr uction that will output the average of a variable over the output interval. The parameters are repetitions - the number of elements in an array to calculate averages for, the Source variable or array to average, the data format to store the result in (Table 4.3-1), and a disable variable that allows excluding readings from the average if conditions are not met. A reading will not be included in th e average if the disable variable is not equal to 0; the example has 0 entered for the disable variable so all readings are included in the average.

TABLE 4.3-1 Formats for Output Data

)

±7999

+2,147,483,647

13 bits (about 4 digits)

1 bit (1)

4.3.2 The Scan -- Measurement Timing and Processing

Once you know what you want, the measurements and calculations have been listed and the output tables defined, the program itself may be relatively short. The executable program begins with BeginProg and ends with EndProg. The measurements, processing, and calls to output tables bracketed by the Scan and NextScan instructions determine the sequence and timing of the datalogging.

BeginProg Scan(1,MSEC,3,0)

ModuleTemp(RefTemp, 250) TCDiff(TC(),6,mV50,4,1,TypeT,RefTemp,RevDiff,Del,Integ,Mult,Offset)

CallTable Temp NextScan EndProg

The Scan instruction determines h ow frequently the measurements within the scan are made:

Scan

(Interval, Units, BufferSize, Count)

Scan(1,MSEC,3,0)

The Scan instruction has four parameters. The scans. one minute. The RAM that holds the raw results of measur ements. Using a buffer allows the processing in the scan to at times lag behind the measurements without affecting the measurement timing (see the scan instruction in Section 9 for more details). instruction following NextScan. A count of 0 means to continue looping

are the time units for the interval. The max im u m scan interval is

Units

BufferSize

Count

Interval

is the size (in the number of scans) of a buffer in

is the number of scans to make before proceeding to the

is the interval between

4-6

forever (or until ExitScan). In the example the scan is 1 millisecond, three scans are buffered, and the measurements and output continue indefinitely.

4.4 Numerical Entries

In addition to entering regular base 10 numbers there are 3 additional ways to represent numbers in a program: scientific notation, binary, and hexadecimal (Table 4.4-1).

TABLE 4.4-1 Formats for Entering Numbers in CRBasic

Format Example Value Standard 6.832 6.832 Scientific notation 5.67E-8 5.67X10 Binary: &B1101 13 Hexadecimal &HFF 255

The binary format makes it easy to visualize operations where the ones and zeros translate into specific commands. For example, a block of ports can be set with a number, the binary form of which represents the status of the ports (1= high, 0=low). To set ports 1, 3, 4, and 6 high and 2, 5, 7, and 8 low; the number is &B00101101. The least significant bit is on the right and represents port 1. This is much easier to visualize than en tering 72, the decimal equivalent.

Section 4. CRBasic - Native Language Programming

-8

4.5 Logical Expression Evaluation

4.5.1 What is True?

Several different words get used to describe a condition or the result of a test. The expression, X>5, is either true or false. However, when describing the state of a port or flag, on or off or high or low sounds better. In CRBasic there are a number of conditional tests or instruction parameters the result of which may be described with one of the words in Table 4.5-1. The CR5000 evaluates the test or parameter as a number; 0 is false, not equal to 0 is true.

TABLE 4.5-1. Syno nyms for True and False

Predefined Constant True (-1) False (0) Synonym High Low Synonym On Off Synonym Yes No Synonym Trigger Do Not Trigger Number Digital port 5 Volts 0 Volts

≠0

4-7

Section 4. CRBasic - Native Language Programming

4.5.2 Expression Evaluation

Conditional tests require the CR5000 to evaluate an expression and take one path if the expression is true and another if the expression is false. For example:

If X>=5 then Y=0

will set the variable Y to 0 if X is greater than or equal to 5.

The CR5000 will also evaluate multiple expressions linked with and or or. For example:

If X>=5 and Z=2 then Y=0

will only set Y=0 if both X>=5 and Z=2 are true.

If X>=5 or Z=2 then Y=0

will set Y=0 if either X>=5 or Z=2 is true (see And and Or in Section 9). A condition can include multiple and and or links.

4.5.3 Numeric Results of Expression Evaluation

The CR5000 expression evaluator evaluates an expression and returns a number. A conditional statement uses the number to decide which way to branch. The conditional statement is false if the number is 0 and true if the number is not 0. For example:

If 6 then Y=0,

is always true, Y will be set to 0 any time the conditional statement is executed.

If 0 then Y=0

is always false, Y will never be set to 0 by this conditional statement.

4.6 Flags

The CR5000 expression evaluator evaluates the expression, X>=5, and returns

-1, if the expression is true, and 0, if the expression is false.

W=(X>Y)

will set W equal to -1 if X>Y or will set W equal to 0 if X<=Y.

The CR5000 uses -1 rather than some other non-zero number because the and and or operators are the same for logical statements and binary bitwise comparisons (see and and or in Section 8). The number -1 is expressed in binary with all bits equal to 1, the number 0 has all bits equal to 0. When -1 is anded with any other number the result is the other number, ensuring that if the other number is non-zero (true), the result will be non-zero

Any variable can be used as a flag as far as logical tests in CRBasic are concerned. If the value of the variable is non-zero the flag is high. If the value of the variable is 0 the flag is low (Section 4.5). PC9000 looks for the variable array with the name Flag when the option to display flag status is used in one of the real time screens.

4-8

4.7 Parameter Types

Instructions parameters allow different types of inputs these types are listed below and specifically identified in the description of the parameter in the following sections or in PC9000 CRBasic help.

Table 4.7-1 list the maximum length and allowed characters for the names for Variables, Arrays, Constants, etc.

TABLE 4.7-1. Rules for Names

Section 4. CRBasic - Native Language Programming

Constant Variable Variable or Array Constant, Variable, or Expression Constant, Variable, Array, or Expression Name Name or list of Names Variable, or Expression Variable, Array, or Expression

Name for Maximum Length (number of

characters)

Variable or Array 16 Letters A-Z, upper or lower. Constant 16 case, underscore “_”, and Alias 16 numbers 0-9. The name must Data Table Name 8 start with a letter. CRBasic is Field name 16 not case sensitive

Allowed characters

4.7.1 Expressions in Parameters

Many parameters allow the entry of expressions. If an expression is a comparison, it will return -1 if the comparison is true and 0 if it is false (Section 4.5.3). An example of the use of this is in the DataTable instruction where the trigger condition can be entered as an expression. Suppose the variable TC(1) is a thermocouple temperature:

DataTable(Name, TrigVar, Size)

DataTable(Temp, TC(1)>100, 5000) Entering the trigger as the expression, TC(1)>100, will cause the trigger to be

true and data to be stored whenever the temperature TC(1) is greater than 100.

4.7.2 Arrays of Multipliers Offsets for Sensor Calibration

If variable arrays are used as the multiplier and offset parameters in measurements that use repetitions, the in str uction will automatically step through the multiplier and offset arrays as it steps through the channels. This allows a single measurement instruction to measure a series of individually

4-9

Section 4. CRBasic - Native Language Programming

calibrated sensors, applying the correct calibration to each sensor. If the multiplier and offset are not arrays, the same m u ltiplier and offset are used for each repetition.

VoltSE(Dest,Reps,Range,ASlot,SEChan,Delay, Integ,Mult,Offset)

'Calibration factors: Mult(1)=0.123 : Offset(1)= 0.23 Mult(2)=0.115 : Offset(2)= 0.234 Mult(3)=0.114 : Offset(3)= 0.224 VoltSE(Pressure(),3,mV1000,6,1,1,100,Mult(),Offset()

4.8 Program Access to Data Tables

Data stored in a table can be accessed from within the program. The format used is:

Tablename.Fieldname(fieldname index,records back)

Where

Tablename

Fieldname

array even if it consists of only one variable; the be specified. from the current time (1 is the most recent record stored, 2 is the record stored prior to the most recent). For example, the expression:

Tdiff=Temp.TC_Avg(1,1)–Temp.TC_Avg(1,101)

could be used in the example program (Section 4.3) to calculate the change in the 10 ms average temperature of the first thermocouple between the most recent average and the one that occurred a second (100 x 10 ms) earlier.

In addition to accessing the data actually output in a table, there are some pseudo fields related to the data table that can be retrieved:

Tablename

table was called, = 0 if data were not output.

Tablename

where:

is the name of the field in the table. The fieldname is always an

.record(1,n) = the record number of the record output n records ago.

.output(1,1) = 1 if data were outpu t to the table the last time the

.timestamp(m,n) = element m of the timestamp output n records ago

timestamp(1,n) = microseconds since 1990

timestamp(2,n) = microseconds into the current year

timestamp(3,n) = microseconds into the current month

timestamp(4,n) = microseconds into the current day

timestamp(5,n) = microseconds into the current hour

timestamp(6,n) = microseconds into the current minute

timestamp(7,n) = microseconds into the current second

is the name of the table in which the desired value is stored.

must always

Records back

fieldname index

is the number of records back in the data table

4-10

Section 4. CRBasic - Native Language Programming

NOTE

Tablename

instruction, the last time the table was called, = 0 if the data table did not sto r e a record or if it is in the middle of an event.

The values of Tablename.output(1,1) and Tablename.eventend (1,1) are only updated when the tables are called.

The WorstCase example in Section 6.2 illu str a tes the use of this syntax.

.eventend(1,1) is only valid for a data table using the DataEvent

Tablename

.eventend(1,1) = 1 if the last record of an event occurred

4-11

Section 4. CRBasic - Native Language Programming

This is a blank page.

4-12

Section 5. Program Declarations

Alias

Used to assign a second name to a variable.

Syntax

Alias

VariableA

Remarks

Alias allows assigning a second name to a variable. Within the datalogger program, either name can be used. Only the alias is av ailable for Public variables. The alias is also used as the root name for data table fieldnames.

With aliases the program can have the efficiency of arrays for measurement and processing yet still have individually named measurements.

Alias Declaration Example

The example shows how to use the Alias declaration.

Dim TCTemp(4)

Alias TCTemp(1) = CoolantT Alias TCTemp(2) = Manifold T Alias TCTemp(3) = Exhau stT Alias TCTemp(4) = CatConvT

VariableB

Const

Declares symbolic constants for use in place of numeric entries.

Syntax

Const

Remarks The Const statement has these parts:

Part Description

constantname expression

Tip Constants can make your programs self-documenting and easier to

Caution Constants must be defined before referring to them.

Tip Use all uppercase letters for constant names to make them easy to

constantname

Name of the constant.

Expression assigned to the constant. It can consist of literals

modify. Unlike variables, constants can't be changed while your program is running.

recognize in your program listings.

expression

(such as 1.0), other constants, or any of the arithmetic or logical operators.

5-1

Section 5. Program Declarations

Dim

Const Declaration Example

The example uses Const to define the symbolic constant PI.

Const PI = 3.141592654 'Define constant. Dim Area, Circum, Radius 'Declare variables. Radius = Volt( 1 ) 'Get measurement. Circum = 2 * PI * Radius 'Calculate circumference. Area = PI * ( Radius ^ 2 ) 'Calculate area.

Declares variables and allocates storage space. In CRBasic, ALL variables MUST be declared.

Syntax

varname

Dim

Remarks The Dim statement has these parts:

Part Description

varname subscripts

subscripts

[([

Name of a variable. Dimensions of an array variable. You can declare multip le dimensions.

]) [,

varname

subscripts

[([

])]]

Public

The argument subscripts has the following syntax: size [size, size]

In CRBasic the Option Base is always 1. This means the lowest number in a dimension is 1 and not 0.

Dim A( 8, 3 )

The maximum number of array dimensions allowed in a Dim statement is 3. If a program uses a subscript that is greater than the dimensioned value, a subscript out of bounds error is recorded.

When variables are initialized, they are initialized to 0

Tip Put Dim statements at the beginning of the program.

Dimensions a variable as public and available in the Public table of the CR5000.

Syntax

Public

Remarks

More than one Public statement can be made.

list of [dimensioned] variables that make up the Public Table

(

)

5-2

Station Name

Section 5. Program Declarations

Public Declaration Example

The example shows the use of the Pu blic declaration.

Dim x( 3 ), y, z( 2, 3, 4 )

Public x, y, z Public Dim x( 3 ), y, z( 2, 3, 4 ) 'Dim is optional Public x( 3 ),y, z( 2, 3, 4 ) Public w

Sets the station name.

Syntax

StationName

Remarks

StationName is used to set the datalogger station name with the program. The station name is displayed by PC9000 and stored in the data table headers (Section 2.4).

StaName

Units

Used to assign a unit name to a field associated with a variable.

Syntax Units

Variable

Remarks

Units allows assigning a unit name to a field. Units are displayed on demand in the real-time windows of PC9000. The unit name also appears in the header of the output files and in the Data Table Info file of PC9000. The unit name is a text field that allows the user to label data. When the u ser m odifies the units, the text entered is not checked by PC9000 or the CR5000.

Example

Dim TCTemp( 1 )

TCTemp( 1 ) = Deg_C

Units

Sub, Exit Sub, End Sub

Declares the name, variables, and code that form a Subro utine.

Syntax

Sub

SubName

[

End Sub

= UnitName

VariableList

[(

statementblock

Exit Sub

statementblock

]

)]

]

5-3

Section 5. Program Declarations

The Sub statement has these parts:

Part Description

Sub Marks the beginning of a Subroutine.

SubName

VariableList

Name of the Subroutine. Because Subroutine n ames are recognized by all procedures in all modules, be the same as any other globally recognized name in the program.

List of variables that are passed to the Subroutine when it is called. The variable names used in this list should not be the same names as variables, aliases, or constants declared elsewhere. The variable names in this list can only be used within the Subroutine. Multiple variables are sep arated by commas. When the Subroutine is called, the call statement must list the program variables or values to pass into the subroutine variable. The number and sequence of the program variables/values in the call statement must match the number and sequence of the variable list in the sub declaration. Changing the value of one of the variables in this list inside the Subroutine changes the v alue of the variable passed into it in the calling procedure.

The call may pass constants or expressions that evaluate to constants (i.e., do not contain a variable) into some of the variables. If a constant is passed, the “ v ariab le” it is passed to becomes a constant and cannot be changed by the subroutine. If constants will be passed, the subroutine should be written to not try to change the value of the “variables” they will be passed into.

subname

cannot

statementblock

Exit Sub Cau s es an immediate exit from a Subroutine. Program

End Sub Marks the end of a Subroutine.

A Subroutine is a procedure that can take variables, perform a series of statements, and change the value of the variables. However, a Subroutine can't be used in an expression. You can call a Subroutine using the name followed by the variable list. See the Call statement for specific information on how to call Subroutines.

The list of Subroutine variables to pass is optional. Subroutines can operate on the global program variables declared by the Public or Dim statements. The advantage of passing variables is that the subroutine can be used to operate on whatever program variable is passed (see example).

Caution Subroutines can be recursive; that is, they can call themselves to

perform a given task. However, recursion can lead to strange results.

Any group of statements that are executed within the body of the Subroutine.

execution continues with the statement follo wing the statement that called the Subroutine. Any number of Exit Sub statements can appear anywhere in a Subroutin e.

5-4

Subroutine Example

'CR5000 'Declare Variables used in Program:

Public RefT, TC(4),PRTresist,PRTtemp,I

'Data output in deg C:

DataTable (TempsC,1,-1)

DataInterval (0,5,Min,10) Average (1,RefT,FP2,0) Average (4,TC(),FP2,0) Average (1,PRTtemp,FP2,0)

EndTable

'Same Data output in F:

DataTable (TempsF,1,-1)

DataInterval (0,5,Min,10) Average (1,RefT,FP2,0) Average (4,TC(),FP2,0) Average (1,PRTtemp,FP2,0)

EndTable

Section 5. Program Declarations

'Subroutine to convert temperature in degrees C to degrees F

Sub ConvertCtoF (Tmp)

Tmp = Tmp*1.8 +32

EndSub

BeginProg

Scan (1,Sec,3,0)

'Measure Temperatures (panel, 4 thermocouples, and 100 ohm PRT) in deg C

PanelTemp (RefT,250) TCDiff (TC(),4,mV20C ,1,TypeT,RefT,True ,0,250,1.0,0) Resistance (PRTresist,1,mV50,7,Ix1,1,500,True ,True ,0,250,0.01,0) PRT (PRTtemp,1,PRTresist,1.0,0)

'Call Output Table for C

CallTable TempsC

'Convert Temperatures to F using Subroutine:

Call ConvertCtoF(RefT)

'Subroutine call using Call statement

For I = 1 to 4

ConvertCtoF(TC(I))

'Subroutine call without Call statement

Next I ConvertCtoF(PRTtemp)

'Subroutine call without Call statement

'Call Output Table for F:

CallTable TempsF

NextScan

EndProg

5-5

Section 5. Program Declarations

This is a blank page.

5-6

Section 6. Data Table Declarations and Output Processing Instructions

6.1 Data Table Declaration

DataTable (Name, TrigVar, Size)

output trigger modifier export data destinations output processing instructions

EndTable

DataTable is used to declare/define a data table. The name of the table, output trigger and size of the table in RAM are set with DataTable. The Tab le declaration must be at the beginning of the code prior to BeginProg. The table declaration starts with DataTable and ends with EndTable. Within the declaration are output trigger modifiers (optional, e.g., DataInterval, DataEvent or WorstCase), the on-line storage devices to send the data to (optional, e.g., CardOut, DSP4), and the output processing instructions describing the data set in the table.

Parameter

& Data Type

Name

TrigVar

Constant Variable, or Expression

Size

Constant

EndTable

Enter

The name for the data tab le. The table name is limited to eight characters.

The name of the variable to test for the trigger. Trigger modifiers add additional conditions.

Value Result

0 Do not trigger

≠

0 Trigger

The size to make the data table. The number of data sets (records) to allo cate memory for in static RAM. Each time a variable or interval trigger occurs, a line (or row) of data is output with the number of values determined by the output Instructions within the table. This data is called a record. The total number of records stored equals the size..

Note

DataTable Example - see native language Section 4.

Enter a negative number and all remaining memory (after creating fixed size data tables) will be allocated to the table or partitioned between all tables with a negative value for size. The partitioning algorithm attempts to have the tables fill at the same time.

Used to mark the end of a data table. See DataTable

6-1

Section 6. Data Table Declarations and Output Processing Instructions

6.2 Trigger Modifiers

DataInterval (TintoInt, Interval, Units, Lapses)

Used to set the time interval for an outpu t tab le. DataI nterval is inserted into a data table declaration following th e DataTable instruction to establish a fixed interval table. The fixed interval table requires less memory than a conditional table because time is not stored with each record. The time of each record is calculated by knowing the time of the most recent output and the interval of the data. DataInterval does not override the Trigger in the DataTable instruction. If the trigger is not set always true by entering a constant, it is a condition that must be met in addition to the time interval before data will be stored.

The Interval determines how frequently data are stored to the tab le. Th e interval is synchronized with the real tim e clo c k . Time is kept internally as the elapsed time since the start of 1990 (01-01-1990 00:00:00). When the interval divides evenly into this elapsed time it is time to output (elapsed time MOD interval = 0). Entering 0 for the I n terval sets it equal to the scan Interval.

TintoInt allows the user to set the time into the I nterval, or offset relative to real time, at which the output occurs([elapsed time + TintoInt] MOD interval =

0). For example, 360 (TintoInt) minutes into a 720 (Interval) minute (Units) interval specifies that output should occur at 6:00 (6 AM, 360 minutes from midnight) and 18:00 (6 PM, 360 minutes from noon) where the 720 minute (12 hour) interval is set relative to midnight 00:00. Enter 0 to keep output on the even interval.

Interval driven data allows a more efficient use of memory because it is not necessary to store time with each record. The CR5000 still stores time but on a fixed spacing, only about once per 1 K of memory used for the table. As each new record is stored, time is checked to ensure that the interval is correct. The datalogger keeps track of lapses or discontinuities in the data. If a lapse has occurred, the CR5000 inserts a time stamp into the data. When the data are retrieved a time stamp can be calculated and stored with each record.

This lapse time stamp takes up some memory that would otherwise be used for data. While the CR5000 allocates some extra memory for the table, if there are a lot of lapses, it is not possible to store as many records as requested in the DataTable declaration. The Lapses parameter allows the programmer to allocate additional space for the number of lapses entered. This is used in particular when the program is written in a way that will create lapses. For example, if the data output is controlled by a trigger (e.g., a user flag) in the DataTable instruction in addition to the DataInterval, lapses would occur each time the trigger was false for a period of time longer than the interval.

To take advantage of the more efficient memory use, always enter 1 or greater for the lapses parameter even if no lapses are expected. Entering 0 causes every record to be time stamped.

Entering a negative number tells the CR5000 not to keep track of lapses. Only the periodic time stamps (approximately once per K of data) are inserted.

6-2

Section 6. Data Table Declarations and Output Processing Instructions

Parameter

& Data Type

TintoInt

Constant

Interval

Constant

Units

Constant

Lapses

Constant

OpenInterval

Enter

The time into the interval (offset to the interval) at which the table is to be output. The units for time are the same as for the interval.

Enter the time interval on which the data in the table is to be recorded. The interval may be in µs, ms, s, or minutes, whichever is selected with the make the data interval the same as the scan interval. The units for the time parameters, PowerOff is the only instruction that uses hours or days.

Alpha Code

USEC 0 microseconds MSEC 1 milliseconds SEC 2 seconds MIN 3 minutes As each new record is stored, time is checked to ensure that the in terval is correct. The datalogger keeps track of lapses or discontinuities in the data.

Numeric Code Units

Units

parameter. Enter 0 to

When the DataInterval instruction is included in a data table, the CR5000 uses only values from within an interval for time series processing (e.g., average, maximum, minimum, etc.). When data are output every interval, the output processing instructions reset each time output occurs. To ensure that data from previous intervals is not included in a processed output, processing is reset any time an output interval is skipped. (An interval could be skipped because the table was not called or another trigger condition was not met.) The CR5000 resets the processing the next time th at the table is called after an output interval is skipped. If this next call to the table is on a scheduled interval, it will not output. Output will resume on the next interval. (If Sample is the only output processing instruction in the table, data will be output any time the table is called on the interval because sampling uses only the current value and involves no processing.)

OpenInterval is used to modify an interval driven table so that tim e series processing in the table will include all values input since the last time the table output data. Data will be output whenever th e tab le is called on the output interval (provided the other trigger conditions are met), regardless of whether or not output occurred on the previous interval.

OpenInterval Example:

In the following example, 5 thermocouples are measured every 500 milliseconds. Every 10 seconds, while Flag(1) is true, the averages of the reference and thermocouple temperatures are output. The user can toggle Flag(1) to enable or disable the output. Without the OpenInterval Instruction, the first averages output after Flag(1) is set high would include only the measurements within the previous 10 second interval. This is the default and is what most users desire. With the Open interval in the program (remove the initial single quote (‘) to uncomment the instruction) all the measurements made while the flag was low will be included in the first averages output after the flag is set high.

6-3

Section 6. Data Table Declarations and Output Processing Instructions

Const RevDiff 1 'Reverse input to cancel offsets Const Del 0 'Use default delay Const Integ 0 'Use no integration Public RefTemp 'Declare the variable used for reference temperature Public TC(5) 'Declare the variable used for thermocouple measurements Public Flag(8) Units RefTemp=degC ' Units TC=degC

DataTable (AvgTemp,Flag(1),1000) 'Output when Flag(1)=true

DataInterval(0,10,sec,10) 'Output every 10 seconds(while Flag(1)=true)

'OpenInterval 'When Not Commented, include data while Flag(1)=false in next average

Average(1,RefTemp,IEEE4,0) Average(5,TC,IEEE4,0)

EndTable BeginProg

Scan(500,mSec,0,0)

PanelTemp (RefTemp,250) TCDiff (TC(),5,mV50C,9,TypeT,RefTemp,RevDiff,Del,Integ,1,0) CallTable AvgTemp

NextScan

EndProg

DataEvent (RecsBefore, StartTrig, StopTrig, RecsAfter)

Used to set a trigger to start storing records and another trigger to stop storing records within a table. The number of records before the start trigger and the number of records after the stop trigger can also be set. A filemark (Section 8) is automatically stored in the table between each event.

Parameter

& Data Type

RecsBefore

Constant

StartTrig The variable or expression test to Trigger copying the pre trigger records into the

Variable, or Expression

StopTrig

Variable, Expression or Constant

RecsAfter

Constant

Enter

The number of records to store before the Start Trigger.

data table and start storing each new record..

Value Result

0 Do not trigger

≠

0 Trigger

The variable, expression or constant to test to stop storing to the data table. The CR5000 does not start checking for the stop trigger until after the Start Trigger occurs. A non-zero (true) constant may be used to store a fixed number of records when the start trigger occurs (total number of records = PreTrigRecs+ 1 record for the trigger +PostTrigRecs.). Zero (false) could be entered if it was desired to continuously store data once the start trigger occurred.

Value Result

0 Do not trigger

≠

0 Trigger

The number of records to store after the Stop Trigger occurs.

6-4

Section 6. Data Table Declarations and Output Processing Instructions

DataEvent Example:

In this example, 5 type T thermocouples are measured. The trigger for the start of an event is when TCTemp(1) exceeds 30 degrees C. The stop trigger is when TCTemp(1) less than 29 degrees C. The event consists of 20 records prior to the start trigger an d continues to store data until 10 records following the stop trigger.

Const RevDiff 1 'Reverse input to cancel offsets Const Del 0 'Use default delay Const Integ 0 'Use no integration Public RefTemp ‘Declare the variable used for reference temperature Public TC(5) 'Declare the variable used for thermocouple measurements Public Flag(8) Units RefTemp=degC ' Units TC=degC

DataTable (Event,1,1000)

DataInterval(0,00,msec,10) 'Set the sample interval equal to the scan DataEvent(20,TC(1)>30,TC(1)<29,10) '20 records before TC(1)>30,

'after TC(1)<29 store 10 more records

Sample(1,RefTemp,IEEE4) 'Sample the reference temperature Sample(5,TC,IEEE4) 'Sample the 5 thermocouple temperatures

EndTable

FillStop

BeginProg

Scan(500,mSec,0,0)

PanelTemp (RefTemp,250)

TCDiff (TC(),5,mV50C,1,TypeT,RefTemp,RevDiff,Del,Integ,1,0)

CallTable Event

NextScan

EndProg

Data Tables are by default ring memory where, once full, the newest data are written over the oldest. Entering FillStop into a data table declaration makes the table fill and stop. Once the table is filled, no more data are stored until the table has been reset. The table can be reset from within the program by executing the ResetTable instruction. Tables can also be reset from PC9000 real time windows or the collect data window.

Example:

DataTable (Temp,1,2000)

DataInterval(0,10,msec,10)

FillStop ' the table will stop collecting data after 2000 records.

Average(1,RefTemp,fp2,0) Average(6,TC(1),fp2,0)

EndTable

6-5

Section 6. Data Table Declarations and Output Processing Instructions

WorstCase (TableName, NumCases, MaxMin, Change, RankVar)

Allows saving the most significant or “worst-case” events in separate data tables.

A data table is created that is sized to hold one event. This table acts as the event buffer. Each event that occurs is stored to this table. This table may use the DataEvent instruction or some othe r condition to determine when an event is stored. The significance of an event is determined by an algorithm in the program and a numerical ranking of the event is stored in a variable.

WorstCase creates as many clones of the specified table as the number of cases for which to keep data. When WorstCase is executed, it checks the ranking variable; if the value of the variable is a new worst case, the data in the event table replace the data in the cloned table that holds the least significant event currently stored.

An additional data table, nameWC (e.g., EvntWC) is created that holds the values of the rank variables for each of the worst case tables and the time that that table was stored.

WorstCase must be used with data tables sent to th e CPU. I t will not work if the event table is sent to the PC card.

Parameter

& Data Type

TableName

name

NumCases

MaxMin

Constant

Change

Constant

RankVar

Variable

While WorstCase acts as Trigger Modifier and a data table declaration (creating the cloned data tables), it is entered within the program to call the worst case tables (see example).

Enter

The name of the data table to clone. The length of this name should be 4 characters or less so the complete names o f the worst case tables are retained when collected (see NumCases). The number of “worst” cases to store. This is the number of clones of the data table to create. The cloned tables use the name of the table being cloned (up to the first 6 characters) plus a 2 digit number (e.g., Evnt01, Evnt02, Evnt03, …). The numbers give the tables unique names, they have no relationship to the ranking of the events. PC9000 uses this same name modification when creating a new data file for a table. To avoid confusion and ambiguous names when collecting data with PC9000, keep the base name four characters or less (4ch aract er base name + 2 digit case identifier + 2 digit collection identifier = 8 character maximum length). A code specifying whether the maximum or minimum events should be saved.

Value Result

The minimum chang e t hat must occur in the RankVariable before a new worst case is stored.

The Variable to rank the events by.

Min

, save the events associ ated with the minimum ranking; i.e., Keep track of the RankVar associated with each event stored. If a new RankVar is less than previous maximum, copy the event over the event with previous maximum)

Max

, save the events associ ated with the maximum ranking; i.e., copy if RankVar is greater than previous lowest (over event with previous minimum)

6-6

Campbell Scientific CR5000 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Warranty and Assistance

TABLE OF CONTENTS

CR5000 Overview

OV1. Physical Description

OV1.1 Measurement Inputs

OV1.1.1 Analog Inputs

OV1.1.2 Signal Grounds ( )

OV1.1.3 Power Grounds (G)

OV1.1.4 Ground Lug

OV1.1.5 Power In

OV1.1.6 Switched 12 Volts SW-12

OV1.1.7 Switched Voltage Excitation (VX)

OV1.1.8 Switched Current Excitation (IX)

OV1.1.9 Continuous Analog Outputs (CAO)

OV1.1.10 Control I/O

OV1.1.11 Pulse Inputs

OV1.1.12 Power Up

OV1.1.13 SDM Connections

OV1.2 Communication and Data Storage

OV1.2.1 PCMCIA PC Card

OV1.2.2 CS I/O

OV1.2.3 Computer RS-232

OV1.3 Power Supply and AC Adapter

OV2. Memory and Programming Concepts

OV2.1 Memory

OV2.2 Measurements, Processing, Data Storage

OV2.3 Data Tables

OV3. PC9000 Application Software

OV3.1 Hardware and Software Requirements

OV3.2 PC9000 Installation

OV3.3 PC9000 Software Overview

OV3.3.1 File

OV3.3.2 Edit

OV3.3.3 Analysis

OV3.3.4 Tools

OV3.3.5 Collect

OV3.3.6 Display

OV3.3.7 Windows

OV3.3.8 Help

OV4. Keyboard Display

OV4.1 Data Display

OV4.1.1 Real Time Tables

OV4.1.2 Setting up Real Time Custom Display

OV4.1.3 Final Storage Tables

OV4.2 Run/Stop Program

OV4.3 File Display

OV4.3.1 File: Edit

OV4.4 Configure Display

OV5. Specifications

Section 1. Installation and Maintenance

1.1 Protection from the Environment

1.2 Power Requirements

1.3 CR5000 Power Supplies

1.3.1 CR5000 Lead Acid Battery BASE

1.3.2 Low Profile CR5000

1.4 Solar Panels

1.5 Direct Battery Connection to the CR5000 Wiring Panel

1.6 Vehicle Power Supply Connections

1.6.1 CR5000 with Battery Base

1.6.2 CR5000 with Low Profile Base (No Battery)

1.7 CR5000 GROUNDING

1.7.1 ESD Protection

1.7.2 Effect of Grounding on Measurements: Common Mode Range

1.7.3 Effect of Grounding on Single-Ended Measurements

1.8 Powering Sensors and Peripherals

1.9 Controlling Power to Sensors and Peripherals

1.9.1 Use of Digital I/O Ports for Switching Relays

1.10 Maintenance

1.10.1 Desiccant

1.10.2 Replacing the Internal Battery

Section 2. Data Storage and Retrieval

2.1 Data Storage in CR5000

2.1.1 Internal Static RAM

2.1.2 PCMCIA PC Card

2.2 Internal Data Format

2.3 Data Collection