Geokon 8020-59 Instruction Manual

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Instruction Manual

Vibrating Wire to Analog Converter

Model 8020-59

No part of this instruction manual may be reproduced, by any means, without the written consent of Geokon, Inc.

The information contained herein is believed to be accurate and reliable. However, Geokon, Inc. assumes no responsibility for

errors, omissions, or misinterpretation. The information herein is subject to change without notification.

(Doc Rev J, 05/18/2018

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Warranty Statement

Geokon, Inc. warrants its products to be free of defects in materials and workmanship, under normal use and service for a period of 13 months from date of purchase. If the unit should malfunction, it must be returned to the factory for evaluation, freight prepaid. Upon examination by Geokon, if the unit is found to be defective, it will be repaired or replaced at no charge. However, the WARRANTY is VOID if the unit shows evidence of having been tampered with or shows evidence of being damaged as a result of excessive corrosion or current, heat, moisture or vibration, improper specification, misapplication, misuse or other operating conditions outside of Geokon's control. Components which wear or which are damaged by misuse are not warranted. This includes fuses and batteries.

Geokon manufactures scientific instruments whose misuse is potentially dangerous. The instruments are intended to be installed and used only by qualified personnel. There are no warranties except as stated herein. There are no other warranties, expressed or implied, including but not limited to the implied warranties of merchantability and of fitness for a particular purpose. Geokon, Inc. is not responsible for any damages or losses caused to other equipment, whether direct, indirect, incidental, special or consequential which the purchaser may experience as a result of the installation or use of the product. The buyer's sole remedy for any breach of this agreement by Geokon, Inc. or any breach of any warranty by Geokon, Inc. shall not exceed the purchase price paid by the purchaser to Geokon, Inc. for the unit or units, or equipment directly affected by such breach. Under no circumstances will Geokon reimburse the claimant for loss incurred in removing and/or reinstalling equipment.

Every precaution for accuracy has been taken in the preparation of manuals and/or software, however, Geokon, Inc. neither assumes responsibility for any omissions or errors that may appear nor assumes liability for any damages or losses that result from the use of the products in accordance with the information contained in the manual or software.

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TABLE of CONTENTS

1. INTRODUCTION .................................................................................................................................................. 1

2. INSTALLING AND CONFIGURING THE 8020-59 SOFTWARE APPLICATION ..................................... 2

CONFIGURING THE COM PORT ........................................................................................................................... 5

2.1

3. QUICK STAR T (SINGLE CHANNEL) ............................................................................................................... 7

4. SINGLE AND MULTI-CHANNEL OPERATION ............................................................................................10

4.1

THEORY OF OPERATION .....................................................................................................................................10

OPERATING MODES ...........................................................................................................................................11

4.2

4.2.1 Single Channel Mode ................................................................................................................................11

4.2.2 16-Channel Multiplex ed M ode ..................................................................................................................12

4.2.3 32-Channel Multiplex ed M ode ..................................................................................................................13

CONVERSION TO “DIGITS” .................................................................................................................................14

4.3

CONNECTION TO A VOLTAGE INPUT DAS ..........................................................................................................15

4.4

CONNECTION TO A CURRENT INPUT DAS ..........................................................................................................15

4.5

TEMPERATURE MEASUREMENT .........................................................................................................................16

4.6

5. COMMUNICATIONS ..........................................................................................................................................17

5.1

COMMAND LINE INTERFACE ..............................................................................................................................17

6. 8020-59 WINDOWS APPLICA TION ..................................................................................................................20

6.1

SOFTWARE INSTALLATION .................................................................................................................................20

STARTIN G TH E 8020-59 APPLICATION ...............................................................................................................20

6.2

COMMUNICATIONS TIMEOUT ERROR .................................................................................................................20

6.3

SINGLE CHANNEL CONFIGURATION ...................................................................................................................21

6.4

16-CHANNEL CONFIGURATION ..........................................................................................................................22

6.5

32-CHANNEL CONFIGURATION ..........................................................................................................................25

6.6

APPENDIX A. SPECIFICATIONS .........................................................................................................................26

8020-59 SPECIFICATIONS ..................................................................................................................................26

A.1

MULTIPLEXER TIMING SPECIFICATIONS ............................................................................................................27

A.2

APPENDIX B. THERMISTOR TEMPERATURE DERI VATION .....................................................................28

APPENDIX C. WIRING CONFIGURATIONS .....................................................................................................29

C.1

VOLTAGE OUTPUT – SINGLE CHANNEL MODE (DIGITAL I/O DAS) ..................................................................29

VOLTAGE OUTPUT – 16-CHANNEL MODE (DIGITAL I/O DAS) .........................................................................30

C.2

VOLTAGE OUTPUT – 32-CHANNEL MODE (DIGITAL I/O DAS) .........................................................................31

C.3

CURRENT OUTPUT – SINGLE CHANNEL MODE (DIGITAL I/O DAS) ..................................................................32

C.4

CURRENT OUTPUT – 16-CHANNEL MODE (DIGITAL I/O DAS): ........................................................................33

C.5

CURRENT OUTPUT – 32-CHANNEL MODE (DIGITAL DAS) ................................................................................34

C.6

VOLTAGE OUTPUT – SINGLE CHANNEL MODE (PLC DAS) ..............................................................................35

C.7

VOLTAGE OUTPUT – 16-CHANNEL MODE (PLC DAS) ......................................................................................36

C.8

VOLTAGE OUTPUT – 32-CHANNEL MODE (PLC DAS) ......................................................................................37

C.9

CURRENT OUTPUT – SINGLE CHANNEL MODE (PLC DAS) .............................................................................38

C.10

CURRENT OUTPUT – 16-CHANNEL MODE (PLC DAS) ....................................................................................39

C.11

CURRENT OUTPUT – 32-CHANNEL MODE (PLC DAS) ....................................................................................40

C.12

APPENDIX D. DATA REDUCTION ......................................................................................................................41

D.1

PRESSURE CALCULATION ..................................................................................................................................41

TEMPERATURE CORRECTION.............................................................................................................................42

D.2

BAROMETRIC CORRECTION (REQUIRED ONLY ON NON-VENTED TRANSDUCERS) ...............................................43

D.3

APPENDIX E. SAMPLE CALIBRATION REPORT ...........................................................................................44

APPENDIX F. IMPROVING THE ACCURACY OF CALCULATED PRESS URES .......................................45

APPENDIX G. BAROMETRIC CORRECTION (NON-VENTED TRANSDUCERS ONLY) .........................46

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FIGURES

IGURE 1 - EXTRAC T ING THE 8020-59 INSTALLER ......................................................................................................... 2

FIGURE 2 - SELECT DESTINATION FOLDER ..................................................................................................................... 2

FIGURE 3 - EXTRACTED 8020-59 INSTALLER ................................................................................................................. 3

FIGURE 4 - INSTALL WIZARD, START SCREEN ................................................................................................................ 3

FIGURE 5 - INSTALL WIZARD, CHOOSE USERS ............................................................................................................... 3

FIGURE 6 - INSTALL WIZARD, CHOOSE START MENU FOLDER ....................................................................................... 4

FIGURE 7 - INSTALL WIZARD, INSTALLATION COMPLETE .............................................................................................. 4

FIGURE 8 - INSTALL WIZARD, LAUNCH 8020-59 APPLICATION ...................................................................................... 5

FIGURE 9 - 8020-59 SOFTWARE APPLICATION, STARTUP DIALOG .................................................................................. 5

FIGURE 10 - COMMUNICATIONS PARAMETERS DIALOG ................................................................................................. 6

FIGURE 11 - SINGLE CHANNEL CONFIGURATION SCREEN .............................................................................................. 8

FIGURE 12 - SINGLE CHANNEL MONITOR ....................................................................................................................... 8

FIGURE 13 - CONTROL SIGNAL SEQUENCE: SINGLE CHANNEL MODE .......................................................................... 11

FIGURE 14 - CONTROL SIGNAL SEQUENCE: 16-CHANNEL MODE (CHANNELS ONE AND TWO ONLY) .......................... 12

FIGURE 15 - CONTROL SIGNAL SEQUENCE: 32-CHANNEL MODE (CHANNELS ONE THROUGH FOUR ONLY) ................ 13

FIGURE 16 - COMMUNICATION TIMEOUT WARNING MESSAGE .................................................................................... 20

FIGURE 17 - 16-CHANNEL CONFIGURATION SCREEN ................................................................................................... 22

FIGURE 18 - 16-CHANNEL MONITOR SCREEN............................................................................................................... 23

FIGURE 19 - CHANNEL ONE MONITOR ......................................................................................................................... 24

FIGURE 20 - 32-CHANNEL MONITOR SCREEN............................................................................................................... 25

FIGURE 21 - CHANNEL THREE MONITOR ...................................................................................................................... 25

FIGURE 22 - 16-CHANNEL MULTIPLEXER TIMING REQUIREMENTS .............................................................................. 27

FIGURE 23 - 32-CHANNEL MULTIPLEXER TIMING REQUIREMENTS .............................................................................. 27

FIGURE 24 - CONNECTION EXAMPLE FOR ONE CHANNEL 8020-59 WITH VOLTAGE OUTPUT TO DIGITAL I/O DAS ..... 29

FIGURE 25 - CONNECTION EXAMPLE FOR 16-CHANNEL MULTIPLEXER, 8020-59 WITH VOLTAGE OUTPUT AND DIGITAL

I/O DAS ............................................................................................................................................................. 30

FIGURE 26 - CONNECTION EXAMPLE FOR 32-CHANNEL MULTIPLEXER, 8020-59 WITH VOLTAGE OUTPUT AND DIGITAL

I/O DAS ............................................................................................................................................................. 31

FIGURE 27 - CONNECTION EXAMPLE FOR ONE CHANNEL 8020-59 WITH CURRENT OUTPUT TO DIGITAL I/O DAS ..... 32

FIGURE 28 - CONNECTION EXAMPLE FOR 16-CHANNEL MULTIPLEXER, 8020-59 WITH CURRENT OUTPUT AND DIGITAL

I/O DAS ............................................................................................................................................................. 33

FIGURE 29 - CONNECTION EXAMPLE FOR 32-CHANNEL MULTIPLEXER, 8020-59 WITH CURRENT OUTPUT AND DIGITAL

I/O DAS ............................................................................................................................................................. 34

FIGURE 30 - CONNECTION EXAMPLE FOR ONE CHANNEL. 8020-59 WITH VOLTAGE OUTPUT, 8020-59 PLC AND PLC

DAS ................................................................................................................................................................... 35

FIGURE 31 - CONNECTION EXAMPLE FOR 16-CHANNEL MULTIPLEXER, 8020-59 W/ VOLTAGE OUTPUT, 8020-59 PLC

PLC DAS .................................................................................................................................................... 36

AND

FIGURE 32 - CONNECTION EXAMPLE FOR 32-CHANNEL MULTIPLEXER, 8020-59 W/ VOLTAGE OUTPUT, 8020-59 PLC

PLC DAS .................................................................................................................................................... 37

AND

FIGURE 33 - CONNECTION EXAMPLE FOR ONE CHANNEL 8020-59 WITH CURRENT OUTPUT, 8020-59 PLC AND PLC

DAS ................................................................................................................................................................... 38

FIGURE 34 - CONNECTION EXAMPLE FOR 16-CHANNEL MULTIPLEXER, 8020-59 W/CURRENT OUTPUT, 8020-59 PLC

PLC DAS .................................................................................................................................................... 39

AND

FIGURE 35 - CONNECTION EXAMPLE FOR 32-CHANNEL MULTIPLEXER, 8020-59 W/CURRENT OUTPUT, 8020-59 PLC

PLC DAS .................................................................................................................................................... 40

AND

FIGURE 36 - VIBRATING WIRE PRESSURE TRANSDUCER CALIBRATION REPORT .......................................................... 44

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TABLES

ABLE 1 - CONNECTOR PINOUT AND SIGNAL DESCRIPTION .......................................................................................... 1

TABLE 2 - THERMISTOR RESISTANCE VERSUS TEMPERATURE .....................................................................................28

TABLE 3 - ENGINEERING UNITS MULTIPLICATION FACTORS ........................................................................................42

EQUATIONS

QUATION 1 - VIBRATING WIRE FREQUENCY TO DIGITS CONVERSION ........................................................................14

EQUATION 2 - ANALOG VOLTAGE OUTPUT ..................................................................................................................14

EQUATION 3 - ANALOG CURRENT OUTPUT ..................................................................................................................14

EQUATION 4 - ANALOG VOLTAGE OUTPUT ..................................................................................................................14

EQUATION 5 - ANALOG CURRENT OUTPUT ..................................................................................................................14

EQUATION 6 - TEMPERATURE DERIVED FROM VOLTAGE OUTPUT ................................................................................16

EQUATION 7 - TEMPERATURE DERIVED FROM CURRENT OUTPUT ................................................................................16

EQUATION 8 - RESISTANCE TO TEMPERATURE .............................................................................................................28

EQUATION 9 - DIGITS CALCULATION ............................................................................................................................41

EQUATION 10 - CONVERT DIGITS TO PRESSURE ...........................................................................................................41

EQUATION 11 - TEMPERATURE CORRECTION ...............................................................................................................42

EQUATION 12 - BAROMETRIC CORRECTION ..................................................................................................................43

EQUATION 13 - CORRECTED PRESSURE CALCULATION ................................................................................................43

EQUATION 14 - SECOND ORDER POLYNOMIAL EXPRESSION.........................................................................................45

EQUATION 15 - LINEARITY CALCULATION ...................................................................................................................45

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1. INTRODUCTION

Number

Signal

Name

GND

Analog Signal Ground

V OUT

Conversion Voltage Output, 0 to 5 Volts

+24V

24 Volt Power In

+24V GND

Ground for 24V Power

I-RET

Return for Conversion Current Output

+12V

12 Volt Power Supply In OR +12V Output, if powered by 24V

GND

Ground for 12 Volt Power

TH+

Thermistor Positive Lead

TH-

Thermistor Negative Lead

C+

Vibrating Wire Positive Lead

C-

Vibrating Wire Negative Lead

VALID

Valid Output:

0V indicates conversion not done

ENABLE

Enable Input:

5V = Conversion Enabled

CLOCK

Clock Input:

32-Channel Mode: 0 → 5V transition = increment channel

I-OUT

VW and Thermistor Conversion Current Output

The Model 8020-59 Vibrating Wire (VW) to Analog Converter is a low cost module that provides a simple way to connect Geokon’s vibrating wire transducers to data acquisition systems that are not capable of reading frequency signals nor able to generate the proper signals required to excite VW transducers. The converter can operate with single transducers, as a standalone device, or with multiple transducers in conjunction with the Geokon Model 8032 Multiplexer. The converter is powered using either a 12V or a 24V supply.

The 8020-59 interface is capable of outputting a 0-5V or 4-20mA signal that is directly proportional to “digits”, a vibrating wire sensor’s native units. These outputs are easily converted to digits via several simple formulas (see Section 4.3). The analog outputs are automatically scaled to minimum and maximum parameters (defaults are 0 and 25,000) and sloped to provide their complete 0-5V or 4-20mA range for each individual transducer. These analog outputs offer 20-bit resolution (one part in 1,048,576) with an accuracy of better than 0.1% of full scale span (0-5V output) throughout the operating temperature range (-20 ºC min, +80 ºC max). In a similar fashion, the temperature reading from the transducer’s thermistor is available with 10-bit resolution (one part in 1024). When configured for single-channel operation, the 8020-59 updates the reading approximately once every second.

Signal Description

5V indicates conversion complete

Single Channel Mode: 0V = VW output (digits) 5V = Temperature output (˚C)

16/32-Channel Mode: 0V = Conversion Disabled

Single Channel Mode: 0V = 8020-59 ON 5V = 8020-59 OFF 16-Channel Mode: 0 → 5V transition = increment channel and select VW Analog or Temperature Analog

Table 1 - Connector Pinout and Signal Description

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2. INSTALLING AND CONFIGURING THE 8 0 20-59 SOFTWARE APPLICATION

A free setup and configuration application is available for download on Geokon’s website, providing a user-friendly way to set up the 8020-59 VW to Analog Converter. Follow the steps below to install the software:

1) After downloading the installer from the Geokon website, right-click on the zip file, “8020-

59_setup.zip”, and select “Extract All…” from the resulting popup menu (see Figure 1).

Figure 1 - Extracting the 8020-59 Installer

2) Another dialog will be displayed showing the editable default destination folder for the

extracted contents (see Figure 2). When satisfied with the destination folder, click on the Extract button to extract the contents of the zipped installer (see Figure 2).

Figure 2 - Select Destination Folder

3) Figure 3 on the following page shows the extracted installer in the destination folder. Double

click on the file, “setup.exe”, to start the install process.

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Figure 3 - Extracted 8020-59 Installer

4) After a few moments, the dialog shown in Figure 4 will be displayed.

Figure 4 - Install Wizard, Start Screen

5) After clicking on the “Next >” button, the dialog shown in Figure 5 is displayed.

Figure 5 - Install Wizard, Choose Users

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6) Choose whether to install the 8020-59 Software Application for all users or just for the

current user (see Figure 5). NOTE: Without administrative privileges on the PC, the only option allowed will be “Install just for me”. After making a selection, click “Next >”; this will bring up the dialog shown in Figure 6.

Figure 6 - Install Wizard, Choose Start Menu Folder

7) The dialog shown in Figure 6 allows the installer to choose where the “shortcut” to launch

the application will be located – the default is the “Geokon” folder. A “shortcut” will also be located on the desktop. Clicking on “Install” begins the process of copying files and causes the dialog box shown in Figure 7 to be displayed:

Figure 7 - Install Wizard, Installation Complete

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8) The installation process is now complete. Clicking “Next >” allows the opportunity to launch

the 8020-59 application when finished by checking the box next to “Launch 8020-59 Application” (see Figure 8). Click on “Finish” (see below) to close the install wizard.

Figure 8 - Install Wizard, Launch 8020-59 Application

2.1 Configuring the COM Port

After launching the 8020-59 Software Application, the first thing that must be done is to configure the COM Port. Click on the “Com Setup” (or press the “Alt” and the “c” key at the same time) to select a COM port for communication with the 8020-59 VW to Analog Converter (See Figure 9).

Figure 9 - 8020-59 Software Application, Startup Dialog

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Select a COM port that corresponds to an available RS-232 communication port, whether it is built-in (such as COM1) or an external one via a USB to Serial Converter (see Figure 10). Some newer PCs are so fast that a small delay between characters is needed to give the 8020-59 time to process the characters. The “Inter-character Delay” is specified in milliseconds.

Figure 10 - Communications Parameters Dialog

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3. QUICK START (SINGLE CHANNEL)

In order to properly set up and use the 8020-59 VW to Analog Converter, a field “Zero Reading” will need to be taken. This is required so that the 0-5V and 4-20mA outputs are scaled correctly for the transducer being monitored. This section will allow the user to quickly set up and obtain valid readings from the 8020-59 Converter:

Equipment Required: Personal Computer (PC) with RS-232 COM port 8020-59 Software Application RS-232 Cable (supplied) VW Transducer VW Transducer Calibration Report

1) Install the 8020-59 software on the PC that will be used to interface to the 8020-59 unit (see

Section 2).

2) Connect the 8020-59 to the computer’s serial port (typically COM1). If using an external

USB to Serial converter, drivers for this device will need to be installed before this step (see Section 2.1).

3) Connect +12VDC to connector pin six OR +24VDC to connector pin three (see Table 1 in

Section 1).

4) Connect the power supply return (or Ground) to connector pin seven OR, if using a 24V

supply, connector pin four, 24V GND (see Table 1).

5) Connect the un-pressurized VW transducer to the 8020-59 (see Table 1):

RED wire to connector pin 10 (C+). BLACK wire to connector pin 11 (C-). WHITE wire to connector pin 8 (TH+). GREEN wire to connector pin 7 (TH-) SHIELD wire to connector pin 1 (GND).

6) Start the 8020-59 program.

7) Click the “Single Channel” button (or press the “Alt” and “s” keys) from the program’s

Startup Dialog (see Section 2.1).

8) The Single Channel Configuration screen should now be displayed (see Figure 11 on the

following page). This screen is used to define the parameters that the 8020-59 uses to read the attached transducer.

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Figure 11 - Single Channel Config ur ation Screen

9) Ensure that the Transducer Model drop-down control is correctly set to the proper VW model

and that the “Use Defaults” checkbox is checked.

10) Click “Activate/Monitor” (or press the “Alt” and “m” keys). The “Upload Confirmation”

dialog will be displayed with the prompt: “Do you want to upload the current settings to the 8020-59?”. Click the “Yes” button. The Single Channel Monitor screen should now appear (see Figure 12), and after several seconds should update with a reading.

Figure 12 - Single Channel Monitor

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11) Note the digits that are displayed. Record the VW reading, barometric pressure, and

temperature. This is what is known as the “initial zero” reading. The “initial zero” reading will be used in future calculations. For example, the VW zero reading will be the R0 value in the pressure calcul ati on s equation: P = (R1 – R0) x GF, where R1 equals the “Current Reading” and GF is the Gage Factor obtained from the calibration report for the sensor being measured. See Appendix D for further information on Data Reduction.

12) Click “Exit” (or press the “Alt” and “e” keys) to return to the Setup Screen.

After setup is complete, the PC is disconnected from the 8020-59 and the sensor is in a pressurized state, the “Current Reading” (R1) “Digits” will need to be calculated from the value read from the analog voltage (V OUT, in volts) or current (I-OUT, in milliamperes) output. See Section 4.3 for more information on how to convert from an analog voltage or current value into digits. Once a “Digits” value has been obtained, translation into other engineering units is accomplished by multiplying the “Digits” value by the Gage Factor for the particular sensor read.

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4. SINGLE AND MULTI-CHANNEL OPERATION

In addition to working as a stand-alone device to interface a single transducer to a Data Acquisition System (DAS), multiple channels may be configured in similar fashion to the Single Channel. The 8020-59 works in conjunction with the 8032 Multiplexer and the user’s Data Acquisition System to select either 1 of 16 or 1 of 32 transducers.

The 8020-59 was developed with multiplexing in mind and uses the same control signals as the Geokon model 8032 Vibrating Wire Multiplexer (for control signal timing requirements, refer to the model 8032 Multiplexer Instruction Manual). With a simple control program executing on the host DAS, it is capable of working with 16 vibrating wire transducers (with thermistors), or 32 transducers (without thermistors). All setup parameters for each channel are stored in internal EEPROM memory, requiring no backup battery and can be retained for years.

The 8020-59 is powered from either a 12V or 24V supply (nominal), and draws approximately 70mA when taking readings. When it is “shut-off”, or between scans when multiplexing, the total current consumption of the 8020-59 is less than 10μA (12V) or 16.5mA (24V).

The 8020-59 setup and configuration utility runs on a PC operating under the Windows operating system and communicates to the 8020-59 via the 8020-59’s RS-232 port. A “Command Line” interface is provided in the 8020-59 internal firmware, with a command set that allows all functions to be easily set up and calibrated.

4.1 Theory of Operation

The 8020-59 provides excitation for a VW transducer using a swept frequency pluck that is optimized for the selected gage type. The period of the resulting VW signal is measured using a 25 MHz clock. This measurement is performed 512 times, resulting in an average period being stored in internal memory. The microprocessor then converts the average period into digits and scales the output accordingly, for the specific transducer being read. This information is then sent to a 20-bit D/A converter, which outputs a voltage (0-5V) that is directly proportional to the average digits. Post-processing circuitry converts this voltage to a non-isolated 4-20mA current signal. In addition, the 20-bit D/A is put through a self-calibration routine at the start of each measurement cycle to minimize errors due to temperature and power supply variations. The resulting 0-5V and 4-20mA signals are brought to the output connector for connection to the input(s) of the host DAS.

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4.2 Operating Modes

The 8020-59 has three modes of operation: single channel mode, 16-Channel mode, and 32Channel mode. Each operation mode is detailed in the subsections below.

4.2.1 Single Channel Mode

In this mode (Figure 13), the 8020-59 will maintain continuous excitation of the VW transducer and provide a continuous 0-5V and 4-20mA output to the host DAS, updated approximately every second.

By controlling the ENABLE input to the 8020-59, the 8020-59 voltage and current outputs (VOUT and IOUT) will either be proportional to the transducer’s digits (ENABLE=0V – or disconnected) or the transducer’s temperature in degrees Centigrade (ENABLE=5V).

By controlling the CLOCK input to the 8020-59, the 8020-59 will either be ON (CLOCK=0V − or disconnected) or OFF (CLOCK=5V).

Figure 13 - Control Signal Sequence: Single Channel Mode

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4.2.2 16-Channel Multiplexed Mode

In this mode (Figure 14), the 8020-59 will excite and provide output only when told to do so from the host DAS. As soon as the 8020-59 is powered, if ENABLE and CLOCK are low (0V), the 8020-59 will go to “sleep” and will wait for commands from the host DAS, drawing less than 10μA from the +12V system power supply (16.5mA if using a +24V system power supply).

When a reading is to be taken, the host system first brings ENABLE high (5V) to enable the 8020-59 and then CLOCK high (5V) to activate channel 1 of 16 (for control signal timing requirements, refer to the model 8032 Multiplexer Instruction Manual). The 802059 will “wake up” and read the transducer connected to channel one of the multiplexer. When the reading is ready (approximately one to two seconds later), the 8020-59 will bring the VALID output high (5V), indicating to the host DAS that the voltage and current outputs (proportional to the digits) are at VOUT and IOUT and are ready to be acquired.

Once the reading is acquired, the host system brings CLOCK low (0V) and then high (5V) again to read the temperature of the transducer. When this reading is ready (<100ms later), the VALID output will again go high (5V), indicating that the voltage and current outputs (now proportional to temperature) are at VOUT and IOUT and are ready to be acquired. When the host DAS again brings CLOCK low (0V) and then HIGH (5V), the 8020-59 and multiplexer increment to channel 2 of 16 and this reading sequence starts over again. This reading sequence may be used for up to 16 transducers.

When the final transducer has been read, the host DAS brings CLOCK and ENABLE both low (0V) to reset the system. The 8020-59 will go back to sleep until it is time for the next reading. Using this feature, up to 16 Vibrating Wire transducers with thermistors may be multiplexed into a single DAS.

Figure 14 - Control Signal Sequence: 16-Channel Mod e (Channels One and Two Only)

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4.2.3 32-Channel Multiplexed Mode

In this mode (Figure 15), the 8020-59 will also excite and provide output only when told to do so from the host DAS. As soon as the 8020-59 is powered, if ENABLE and CLOCK are low (0V), the 8020-59 will go to “sleep” and will wait for commands from the host DAS, drawing less than 10μA from the +12V system power supply (16.5mA if using a +24V system power supply).

When a reading is to be taken, the host system first brings ENABLE high (5V) to enable the 8020-59 and then CLOCK high (5V) to activate channel 1 of 32 (for control signal timing requirements, refer to the model 8032 Multiplexer Instruction Manual). The 802059 will “wake up” and read the transducer connected to channel one of the multiplexer. When the reading is ready (approximately one to two seconds later (typ)), the 8020-59 will bring the VALID output high (5V), indicating to the host DAS that the voltage and current outputs (proportional to the digits of transducer number one) are at VOUT and IOUT and are ready to be acquired.

Once the reading is acquired, the host system brings CLOCK low (0V), and then high (5V) again to increment the 8020-59 and multiplexer to the next transducer. When this reading is ready ( approximately one to two seconds later), the VALID output will again go high (5V), indicating that the voltage and current outputs (proportional to the digits of transducer number two) are at VOUT and IOUT and are ready to be acquired. This reading sequence may be used for up to 32 transducers.

When the final transducer has been read, the host DAS brings CLOCK and ENABLE both low (0V) to reset the system. The 8020-59 will go back to sleep until it is time for the next reading. Using this feature, up to 32 Vibrating Wire transducers may be multiplexed into a single DAS.

Figure 15 - Control Signal Sequence: 32-Channel Mode (Channels One through Four Only)

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4.3 Conversion to “Digits”

A useful frequency related unit that is directly proportional to pressure is the “digit”. These units are related to vibrating wire frequency as:

Digits = [Frequency (Hz)]² x 0.001

Equation 1 - Vibrating Wire Frequency to Digits Conversion

The 8020-59 provides analog outputs that are directly proportional to digits.

Referring to the sample calibration in Figure 36 of Appendix E, a value in digits can be derived from the voltage and current outputs as described below.

For the following “positive slope” transducers: 4000, 4100, 4150, 4200, 4210, 4300, 4350, 4360, 4400, 4420, 4425, 4450, 4650 and 4700; use Equation 2 for Analog Voltage Output (assumes Vout is in volts (V)), or Equation 3 for Analog Current (4-20mA) Output (assumes Iout is in milliamperes (mA).

Digits = (Vout * (Digits Span/5V)) + Minimum Limit

Equation 2 - Analog Voltage Output

Digits = ((I out - 4mA) * (Digits Span/16mA)) + Minimum Limit

Equation 3 - Analog C ur rent Output

For the following “negative slope” transducers: 4500, 4600, 4675, 4800 and 4900; use Equation 4 for Analog Voltage Output (assumes Vout is in Volts (V)), or Equation 5 for Analog Current (4-20mA) Output (assumes Iout is in milliamperes (mA)).

Digits = Maximum Limit – (Vout * (Digits Span/5V))

Equation 4 - Analog Voltage Output

Digits = Maximum Limit – ((Iout - 4mA) * (Digits Span/16mA))

Equation 5 - Analog C ur rent Output

Where:

Minimum Limit = Minimum limit parameter set in the channel specific setup screen of the 8020-59 configuration utility (default is zero)

Maximum Limit = maximum limit parameter set in the channel specific setup screen of the 8020-59 configuration utility (default is 25,000)

Digits Span = Maximum Limit - Minimum Limit

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Example: (Assumes the use of default values and transducer type of 4500S-100):

Minimum Limit = 0 digits Maximum Limit = 25,000 digits Digits Span = 25,000 – 0 = 25,000 digits

Vout = 3.250V

Digits = Maximum Limit – (Vout * (Digits Span/5V)) Digits = 25,000 – (3.25V * (5000 digits/V)) Digits = 25,000 – 16,250 Digits = 8750

4.4 Connection to a Voltage Input DAS

The 8020-59 outputs a voltage (V OUT, 0-5V) that is proportional to the digits of the transducer being read (ENABLE = 0V (or disconnected) in Single Channel Mode, after the first of two CLOCKS in 16-Channel Mode, or after each CLOCK in 32-Channel Mode). The 8020-59 offers a digits to voltage output with 20-bit resolution (one part in 1,048,576) of the span of the transducer (default span is 25,000 digits). This output voltage can be input directly to any Data Acquisition System capable of reading a 0-5V analog voltage.

The 8020-59 also outputs a voltage proportional to the temperature (also on V OUT) of the transducer being read (ENABLE = 5V in Single Channel Mode or after the second of two CLOCKS in 16-Channel Mode). The 8020-59 offers a temperature voltage output with 10-bit resolution (one part in 1024) over a 100º C span (-20º C to +80º C). See Section 4.6 for specific calculations.

4.5 Connection to a Current Input DAS

The 8020-59 sources a current (I-OUT, 4-20mA) that is proportional to the digits of the transducer being read (ENABLE = 0V (or disconnected) in Single Channel Mode, after the first of two CLOCKS in 16-Channel Mode, or after each CLOCK in 32-Channel Mode). The 8020-59 offers a digits current output with 20-bit resolution (one part in 1,048,576) of the span of the transducer (default span is 25,000 digits). This output current can be input directly to any Data Acquisition System capable of reading a non-isolated 4-20mA analog current.

The 8020-59 also outputs a current proportional to the temperature (also on I-OUT) of the transducer being read (ENABLE = 5V in Single Channel Mode or after the second of two CLOCKS in 16-Channel Mode). The 8020-59 offers a temperature current output with 10-bit resolution (one part in 1024) over a 100º C span (-20º C to +80º C). See Section 4.6 for specific calculations.

See Appendix C for the various voltage and current measurement options.

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4.6 Temperature Measurement

The 8020-59 is capable of reading the thermistor that is part of a VW sensor. The 8020-59 outputs this reading as a voltage (0-5V) and current (4-20mA) that are proportional to temperature whenever ENABLE is high (5V), in Single Channel Mode, or while the second clock pulse is high, in 16-Channel mode. See Figure 14 for 16-Channel mode control signal timing.

Temperature is derived from the voltage output by Equation 6. Note: Assumes Vout is in volts (V). Minimum Temperature = -20 °C, Degree Span = 100°.

°C = Minimum Temperature + (Vout * (De gree Span / 5V)) =

-20° + (20 * Vout)

Equation 6 - Temperature Derived from Voltage Output

Temperature is derived from the current output by Equation 7. Note: Assumes Iout is in milliamperes (mA).

° C = Minimum Temperature + ((Iout - 4mA) * (Degree Span / 16mA)) =

-20° + (6.25 * (Iout - 4mA))

Equation 7 - Temperature Derived from Current Output

Page 23

5. COMMUNICATIONS

The 8020-59 offers a standard 9-pin RS-232 Serial Port for connection to most desktop and laptop computers (an optional USB to Serial interface adapter is available).

If using a terminal emulator program such HyperTerminal, Putty, etc., for command line set up (see Section 5.1) of the 8020-59, configure the program’s communication parameters as follows:

Port: Serial port that 8020-59 is connected to (i.e., COM1, COM2) Bits per Second: 9600 Data bits: 8 Parity: None Stop bits: 1 Flow Control: None

5.1 Command Line Interface

When connected to a computer using a terminal emulator program such as HyperTerminal, typing <Enter> returns the title screen:

Geokon, Inc 8020-59 VW to Analog Interface Rev 4.0.2 12/05/2011 Type ? for Help

Typing ? <Return> returns the Help Screen:

*? COMMAND DESCRIPTION C1 Single VW and Thermistor C2 16 VW's and 16 Thermistors C3 32 VW's

D# Display Channel # Parameters D0 Display ALL Channel Parameters (C2 & C3 only)

E# Enable channel # (C2 and C3 only) E0 Enable ALL Channels (C2 and C3 only)

ME Enable output monitor MD Disable output monitor

U#,ddddd,+/-,g Store Upper digits,channel #,digits (25000 Max.),slope,gage type L#,ddddd Store Lower digits,channel #,digits (160 Min.)

RD Ready Disabled RE Ready Enabled

N# Disable channel # (C2 & C3 only) N0 Disable ALL Channels (C2 and C3 only)

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X4 Calibrate 4mA X12 Calibrate 12mA X20 Calibrate 20mA

S Display 8020-59 Status R Display Firmware Revision

Z Shutdown and Sleep <Esc> Exit and Start Taking Readings (C1 only) *

Commands C1, C2 and C3 configure the 8020-59 for single channel, 16-Channel multiplexing or 32-Channel multiplexing, respectively.

Note: The default value for the lower limit is zero, so for cases where this is acceptable, there is no need to explicitly set the lower limit.

Typing “D” and the channel # <Enter> displays the limits and slope for that channel. Typing “D0” <ENTER> displays the limits and slope for all channels.

Typing “E” and the channel # <Enter> ENABLES that channel (16 and 32-Channel mode only) when multiplexing. Typing “E0” <ENTER> enables all channels.

Commands ME and MD enable and disable the readings monitor.

To set the maximum digits, slope and gage type for each transducer, type “U” and the channel # (comma) maximum digits (comma) slope (+/-) (comma) gage type <Enter> Example: *U1,10590,-,1 <Enter>

To set the minimum digits type “L” and the channel # (comma) minimum digits <Enter> Example: *L1,9990 <Enter>

Command RD disabled the VALID line from activating when a non-successful vibrating wire sensor conversion takes place. A high level on the VALID line would then indicate that a successful conversion took place.

Command RE enables the VALID line to go “Ready” (high) after each CLOCK pulse while the ENABLE line is high. The VALID output then indicates that the CLOCK and ENABLE sequencing was proper but does not reflect the success of the vibrating wire sensor conversion. The default state for the 8020-59 is READY ENABLED.

Typing “N” and the channel # <Enter> DISABLES that channel (16 and 32-Channel mode only) when multiplexing. Typing “N0” <ENTER> disables all channels.

Typing “X4” <Enter> will allow calibration of the 4mA set point.

Typing “X12” <Enter> will allow calibration of the 12mA set point.

Typing “X20” <Enter> will allow calibration of the 20mA set point.

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Typing “S” <Enter> displays the 8020-59 status:

*S Monitor Enabled Configuration 2: 16 VW’s and 16 Thermistors 1,5000,1000,+,Enabled 2,25000,160,+,Disabled 3,25000,160,+,Disabled 4,25000,160,+,Disabled 5,25000,160,+,Disabled 6,25000,160,+,Disabled 7,25000,160,+,Disabled 8,25000,160,+,Disabled 9,25000,160,+,Disabled 10,25000,160,+,Disabled 11,25000,160,+,Disabled 12,25000,160,+,Disabled 13,25000,160,+,Disabled 14,25000,160,+,Disabled 15,25000,160,+,Disabled 16,25000,160,+,Disabled

Typing “R” <Enter> will return the firmware revision.

Typing “Z” <Enter> will put the 8020-59 into low power sleep mode (off), drawing less than 10μA from the 12V power source (less than 16.5mA from the 24V power source).

Finally, pressing the <Esc> key (in C1 single channel mode only) will start the readings screen with the 8020-59 outputting 0-5V and 4-20mA:

1,11665.75,22.8,-,1,# 1,11665.95,22.7,-,1,# 1,11666.50,22.8,-,1,# 1,11666.60,22.8,-,1,# 1,11667.05,22.8,-,1,# 1,11666.55,22.9,-,1,# 1,11666.10,22.8,-,1,# 1,11665.65,22.8,-,1,# 1,11666.30,22.9,-,1,# 1,11666.50,22.8,-,1,# 1,11666.65,22.8,-,1,# 1,11666.35,22.8,-,1,# 1,11665.85,22.8,-,1,# 1,11666.10,22.8,-,1,# 1,11666.60,22.8,-,1,#

Where; Comma delimited field one is the channel number, followed by the reading in digits, then the transducer temperature in deg. C, the slope, and finally the gage type. The pound sign (#) signifies the end of the data string.

Page 26

6. 8020-59 WINDOWS APPLICATION

All of the commands described in the Command Line Interface Section 5.1 of this manual are included in a simple Windows program designed to set up, control and monitor the 8020-59. This software is provided as a convenient way to set and store the various parameters associated with each transducer, and to monitor the digits and temperature output of each transducer. All settings such as communications parameters, channel enable, individual transducer type, upper limits (digits), lower limits (digits), and transducer model are set using a simple and intuitive user interface.

6.1 Software Installation

Included with the Model 8020-59 VW to Analog Converter is a CD-ROM containing the 802059 application. For more details about installing and configuring the application, please see Section 2.

6.2 Starting the 8020-59 Application

To start the 8020-59 application, select Start/Programs/8020_59/8020_59. This brings up the Startup dialog (see Figure 9).

From the Startup dialog, the major functions (Mode, Communications, and Calibration) of the 8020-59 can be accessed. Click Com Setup to select the Com Port that the 8020-59 is connected to (see Section 2.1 and Figure 10).

After the communication port that the 8020-59 is attached to is selected, click Save/Apply to return to the Startup dialog. The communication port selected will be saved to a configuration file and will not need to be set again unless the communication port changes.

6.3 Communications Timeout Error

If communications to the 8020-59 are interrupted for any reason, after approximately 15 seconds an error message will be displayed with a descriptive error status message in bold font (see Figure 16).

Figure 16 - Communication Timeout Warning Message

NOTE: In Single Channel Mode, the ENABLE line may indeed be active although the PC

should still be able to communicate with 8020-59 VW to Analog Converter.

Page 27

6.4 Single Channel Configuration

If the 8020-59 is to be used with only one transducer, the 8020-59 Mode should be set to Single Channel. Click “Single Channel” (or press the “Alt” and “s” keys) to display the Single Channel Configuration window (see Figure 11).

From this window, all of the transducer information may be entered. The transducer limits, transducer type, and slope are stored in non-volatile EEPROM internal to the 8020-59. All other information is stored to a configuration file on the host computer’s hard drive, and loaded automatically when this screen is displayed. Configurations may also be saved by using the “Save Info” button and opened later by using the “Open Info” button. Opened configurations must be sent to the 8020-59 by using the “Update Info” button to take effect.

From the Transducer Model drop-down list box, select the model of the transducer being used. This selection determines the transducer type/slope and these parameters will be set with no further interaction from the user. Enter the transducer’s limits (in digits) in the text boxes labeled, Maximum (digits) and Minimum (digits). If desired, enter a Label for the transducer.

NOTE: Minimum and maximum values can be obtained from the transducer’s calibration report by taking the lowest average reading for the minimum value and the highest average reading for the maximum value. Another option is to click on “Use Defaults” checkbox in the Limits section of the setup dialog. As of firmware revision 4.0.0, the default minimum and maximum values are 0 and 25,000, respectively. With its 20-bit Digital to Analog Converter, the 8020-59 has more than enough resolution to allow the entire voltage or current range to be divided by 25,000. This can make setup easier than previous firmware revisions.

When complete, click ‘Update Info’ to store this information to the 8020-59. (Note: to determine the information settings of the currently connected 8020-59, click “Retrieve Info”)

Clicking “Activate/Monitor” (or press the “Alt” and “m” keys) starts the 8020-59 transducer excitation and reading output functions and displays the Single Channel Monitor screen (see Figure 12). This screen displays the transducer information along with the reading in digits or microstrain (μE), the calculated reading voltage, the calculated reading current, the temperature of the transducer, and the calculated voltage and current that is representative of the temperature. The screen updates approximately every three to five seconds, providing an almost real-time display of the transducer output.

NOTE: In Single Channel Configuration, the user selects whether the actual voltage and current outputs represent the VW reading or the VW temperature by toggling the ENABLE control line (5V=VW temperature, 0V=VW reading). When left unconnected, the physical voltage and current outputs default to the VW reading.

If monitoring of the 8020-59 outputs is not of interest, then click Activate/Exit from the Configuration Window to begin the transducer excitation and reading and return to the Main Menu.

Page 28

6.5 16-Channel Configuration

The 8020-59 can be used in conjunction with the Geokon model 8032 Multiplexer to configure and monitor up to 16 vibrating wire transducers with thermistors. For wiring details of this configuration, see Appendix C. The 8020-59 Mode should be set to 16-Channel. Clicking “16- Channel” (or press the “Alt” and “1” keys) from the Startup dialog displays the 16-Channel Configuration window:

Figure 17 - 16-Channel Configuration Screen

From this window, all of the transducer information for each of the 16-Channels may be entered. The transducer type, slope, and limits are stored in non-volatile EEPROM internal to the 8020-

59. All other information is stored to a configuration file on the host computer’s hard drive, and loaded automatically when this screen is displayed. Configurations may also be saved by clicking the “Save Info” button and may be recalled later by clicking the “Open Info” button.

Page 29

From the Channel Selection section of the 16-Channel Configuration screen (see Figure 17), select the transducer channel to be configured by clicking on the up arrow (▲) or down (▼)arrow. Alternately, a number from one to 16 can be entered directly. Check “Enable” if the channel is to be read, otherwise uncheck “Enable”. The circle in the upper right corner indicates if the channel is currently enabled or not. Green is enabled, and red is disabled.

In the Transducer Information section, select the model of the transducer being used from the “Transducer Model” drop-down list box. This selection determines the transducer type/slope and these parameters will be set with no further interaction from the user. If desired, enter a “Label” for the transducer.

In the Transducer Limits section, the current minimum and maximum settings for the channels stored in the 8020-59’s on-board EEPROM are in the gray fields on the right. New values in the configuration are in the white fields on the left. Enter the transducer’s limits (in digits) from the transducer’s calibration report at “Maximum (digits)” and “Minimum (digits)”. Alternately, clicking on the “Use Defaults” checkbox will set the minimum and maximum limits to 0 and 25,000, respectively.

When complete, click “Update Info” to store this information to the 8020-59. To update all of the channels with the current configuration click “Update All Info”. To retrieve the info from the 8020-59’s EEPROM for the current configuration, click “Retrieve Info” for the current channel and “Retrieve All Info” for all channels. The “Copy” button may be used to copy the current channels settings, and the “Paste” button may be used to write the current copied settings into the currently selected channel. If the “Increment Channel Selection Before Paste” checkbox is checked, the “Paste” button may be clicked repeatedly to rapidly set the parameters of all channels to the same values. The “Label” textbox will automatically populate with channel appropriate text.

Clicking “Activate/Monitor” puts the 8020-59 into low power Standby (Sleep) mode, waiting for the proper control signals on the ENABLE and CLOCK inputs (refer to Section 4.2.2,16Channel Multiplexed Mode and Figure 22 in Appendix A.2, for signal timing details) and displays the Monitor screen (see Figure 18).

Figure 18 - 16-Channel Monitor Screen

Page 30

The 16-Channel Monitor Screen (see Figure 18) displays the readings and temperatures of any enabled transducers. Any under-range or over-range conditions are highlighted in red and the channels that are currently being read is highlighted in green and yellow. (Note: Any channels that are disabled will be “grayed-out”. Any channels that are enabled but do not have a transducer connected will display 99999 and be highlighted in red). Hovering the mouse in the lower-left corner of any channel’s frame (border) displays the tooltip: “Double-click to expand”. Double-clicking where indicated activates the reading screen (Figure 19) for that channel:

Figure 19 - Channel One Monitor

This screen displays the transducer information along with the reading in digits or

microstrain (μE), the calculated reading voltage, the calculated reading current, the

temperature of the transducer, and the calculated voltage and current that is representative of the temperature. The screen updates based on ENABLE and CLOCK timing from the Data Acquisition System.

If monitoring the 8020-59 outputs is not of interest, then click Activate/Exit from the Configuration Window to put the 8020-59 into low power Standby (Sleep) mode, waiting for the proper control input signals (refer to Section 4.2.2, for signal timing details).

Page 31

6.6 32-Channel Configuration

32-Channel Configuration and Monitor modes work identically to their 16-Channel counterparts with the only difference being that there are no temperature measurements (see Figure 20).

Figure 20 - 32-Channel Monitor Screen

Figure 21 - Channel Three Monitor

Page 32

Physical:

Dimensions (L x W x H):

111.13 mm, 108.36 mm x 36.53 mm

4.375" x 4.266" x 1.438"

Weight:

0.456 lbs.

Operating Temperature:

-20 to +80 degrees Celsius

Power Requirements:

+12V Input Voltage Range:

9 to 15 VDC (12V nominal)

+24V Input Voltage Range:

18 to 30 VDC (24V nominal)

Operating Current:

90mA (max) at 12V @ 25 ºC 75mA (max) at 24V @ 25 ºC

Sleep Current:

10uA (max) at 12V @ 25 ºC

16.5mA (max) at 24V @ 25 °C

VW Frequency Range:

400 – 5000 Hz

Internally Generated Fsweep (pluck):

Gage Type 0:

Frequency (start): 400 Hz

Sweep Shape: Linear

Gage Type 1:

Frequency (start): 1400 Hz

Sweep Shape: Linear

Gage Type 2:

Frequency (start): 2800 Hz

Sweep Shape: Linear

Gage Type 3:

Frequency (start): 400 Hz

Sweep Shape: Linear

Gage Type 4:

Frequency (start): 1200 Hz

Sweep Shape: Linear

Gage Type 5:

Frequency (start): 2500 Hz

Sweep Shape: Linear

Gage Type 6:

Frequency (start): 800 Hz

Sweep Shape: Linear

Accuracy:

Vibrating Wire (0-5V output):

≤ ± 0.1% of Full Scale over temperature

Vibrating Wire (4-20mA output):

≤ ± 0.5% of Full Scale over temperature

Temperature:

≤ ± 0.5% of Full Scale over temperature

Voltage Output Resolution (20 bit):

4.77 uV

Current Output Resolution (20 bit):

0.015 uA

APPENDIX A. SPECIFICATIONS

A.1 8020-59 Specifications

Frequency (end): 5000 Hz Sweep Duration: 200 mSec

Frequency (end): 3500 Hz Sweep Duration: 50 mSec

Frequency (end): 4500 Hz Sweep Duration: 60 mSec

Frequency (end): 1200 Hz Sweep Duration: 300 mSec

Frequency (end): 2800 Hz Sweep Duration: 120 mSec

Frequency (end): 6000 Hz Sweep Duration: 50 mSec

Frequency (end): 1600 Hz Sweep Duration: 50 mSec

Page 33

Digital Control Input – ENABLE:

(Single Channel) 5V CMOS levels:

0V = VW OUT 5V = °C OUT

(Multiplexed) 5V CMOS levels:

0V = SLEEP 5V = READ

Digital Control Input – CLOCK:

(Single Channel) 5V CMOS levels:

0V = ON 5V = OFF

(Multiplexed) 0-5V transition:

Channel increment

Digital Control Output – VALID:

5V CMOS levels:

0V = READING

READY

Thermistor Excitation Voltage:

2.5 VDC

Enable

Clock

Channel 1

No Channel

Selected

No Channel

Selected

Channel 16

Pulse 1

Pulse 2

Pulse 31

Timing:

T2, T4 = indefinate

T3 = 250 µsec( min.)

T1,T5 = 250 µsec(min.)

Selected

Pulse 32

Enable

Clock

Channel 1

Channel 2

No Channel

Selected

No Channel

Selected

Channel 32

Pulse 1

Pulse 2

Pulse 32

Selected

Timing:

T2 = indefinate

T1,T3 = 250 µsec(min.)

A.2 Multiplexer Timing Specifications

NOT READY 5V = READING

Figure 22 - 16-Channel Multiplexer Timing Requirements

Figure 23 - 32-Channel Multiplexer Timing Requirements

Page 34

Ohms

Temp

Ohms

Temp

Ohms

Temp

Ohms

Temp

Ohms

Temp

201.1K

-50

16.60K

-10

2417

+30

525.4

+70

153.2

+110

187.3K

-49

15.72K

-9

2317

507.8

149.0

111

174.5K

-48

14.90K

-8

2221

490.9

145.0

112

162.7K

-47

14.12K

-7

2130

474.7

141.1

113

151.7K

-46

13.39K

-6

2042

459.0

137.2

114

141.6K

-45

12.70K

-5

1959

444.0

133.6

115

132.2K

-44

12.05K

-4

1880

429.5

130.0

116

123.5K

-43

11.44K

-3

1805

415.6

126.5

117

115.4K

-42

10.86K

-2

1733

402.2

123.2

118

107.9K

-41

10.31K

-1

1664

389.3

119.9

119

101.0K

-40

9796 0 1598

376.9

116.8

120

94.48K

-39

9310

1535

364.9

113.8

121

88.46K

-38

8851 2 1475

353.4

110.8

122

82.87K

-37

8417 3 1418

342.2

107.9

123

77.66K

-36

8006 4 1363

331.5

105.2

124

72.81K

-35

7618 5 1310

321.2

102.5

125

68.30K

-34

7252 6 1260

311.3

99.9

126

64.09K

-33

6905 7 1212

301.7

97.3

127

60.17K

-32

6576 8 1167

292.4

94.9

128

56.51K

-31

6265 9 1123

283.5

92.5

129

53.10K

-30

5971

1081

274.9

90.2

130

49.91K

-29

5692

1040

266.6

87.9

131

46.94K

-28

5427

1002

258.6

85.7

132

44.16K

-27

5177

965.0

250.9

83.6

133

41.56K

-26

4939

929.6

243.4

81.6

134

39.13K

-25

4714

895.8

236.2

79.6

135

36.86K

-24

4500

863.3

229.3

77.6

136

34.73K

-23

4297

832.2

222.6

75.8

137

32.74K

-22

4105

802.3

216.1

73.9

138

30.87K

-21

3922

773.7

209.8

72.2

139

29.13K

-20

3748

746.3

203.8

100

70.4

140

27.49K

-19

3583

719.9

197.9

101

68.8

141

25.95K

-18

3426

694.7

192.2

102

67.1

142

24.51K

-17

3277

670.4

186.8

103

65.5

143

23.16K

-16

3135

647.1

181.5

104

64.0

144

21.89K

-15

3000

624.7

176.4

105

62.5

145

20.70K

-14

2872

603.3

171.4

106

61.1

146

19.58K

-13

2750

582.6

166.7

107

59.6

147

18.52K

-12

2633

562.8

162.0

108

58.3

148

17.53K

-11

2523

543.7

157.6

109

56.8

149

Table 2 - Thermistor Resistance Versus Temperature

55.6

150

APPENDIX B. THERMISTOR TEMPERATURE DERIVATION

Thermistor Type: YSI 44005, Dale #1C3001-B3, Alpha #13A3001-B3 Resistance to Temperature Equation:

A+B(LnR)+C(LnR)

Equation 8 - Resistance to Temperature

Where; T = Temperature in °C. LnR = Natural Log of Thermistor Resistance

A = 1.4051 × 10-3 B = 2.369 × 10-4 C = 1.019 × 10-7

Note: Coefficients calculated over the −50 to +150° C. span.

-273.2

Page 35

APPENDIX C. WIRING CONFI G URATIONS

C.1 Voltage Output – Single Channel Mode (Digital I/O DAS)

Figure 24 - Connection Example for One Channel 8020-59 with Voltage Output to Digital I/O DAS

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C.2 Voltage Output – 16-Channel Mode (Digital I/O DAS)

Figure 25 - Connection Example for 16-Channel Multiplexer, 8020-59 with Voltage Output and Digital I/O DAS

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C.3 Voltage Output – 32-Channel Mode (Digital I/O DAS)

Figure 26 - Connection Example for 32-Channel Multiplexer, 8020-59 with Voltag e Output and Digital I/O DAS

Page 38

C.4 Current Output – Single Channel Mode (Digital I/O DAS)

Figure 27 - Connection Example for One Channel 8020-59 with Current Output to Digital I/O DAS

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C.5 Current Output – 16-Channel Mode (Digital I/O DAS):

Figure 28 - Connection Example for 16-Channel Multiplexer, 8020-59 with Current Output and Digital I/O DAS

Page 40

C.6 Current Output – 32-Channel Mode (Digital DAS)

Figure 29 - Connection Example for 32-Channel Multiplexer, 8020-59 with Current Output and Digital I/O DAS

Page 41

C.7 Voltage Output – Single Channel Mode (PLC DAS)

Figure 30 - Connection Example for One Channel. 8020-59 with Voltage Output, 8020-59 PLC and PLC DAS

Page 42

C.8 Voltage Output – 16-Channel Mode (PLC DAS)

Figure 31 - Connection Example for 16-Channel Multiplexer, 8020-59 w/ Voltage Output, 8020-59 PLC and PLC DAS

Page 43

C.9 Voltage Output – 32-Channel Mode (PLC DAS)

Figure 32 - Connection Example for 32-Channel Multiplexer, 8020-59 w/ Voltage Output, 8020-59 PLC and PLC DAS

Page 44

C.10 Current Output – Single Channel Mode (PLC DAS)

Figure 33 - Connection Example for One Channel 8020-59 with Current Out put, 8020-59 PLC and PLC DAS

Page 45

C.11 Current Output – 16-Channel Mode (PLC DAS)

Figure 34 - Connection Example for 16-Channel Multiplexer, 8020-59 w/Current Output, 8020-59 PLC and PLC DAS

Page 46

C.12 Current Output – 32-Channel Mode (PLC DAS)

Figure 35 - Connection Example for 32-Channel Multiplexer, 8020-59 w/Current Output, 8020-59 PLC and PLC DAS

Page 47

APPENDIX D. DATA REDUCTION

D.1 Pressure Calculation

The digits that are calculated from the voltage and current outputs are based on the equation:

Digits =

󰇡

Period

x 10-3

󰇢

Digits=

Equation 9 - Digits Calculation

For example, a piezometer reading 8000 digits corresponds to a period of 354 µs and a frequency of 2828 Hz. Note that in the above equation, the period is in seconds.

Digits are directly proportional to the applied pressure.

1000

Pressure =

(Current Reading - Initial Zero Reading) × Linear Calibration Factor

P = (R1 – R0) ×G

Equation 10 - Convert Digits to Pressure

Since the linearity of most sensors is within 0.2% FS the errors associated with non-linearity are of minor consequence. However, for those situations requiring the highest accuracy it may be desirable to use a second order polynomial to get a better fit of the data points. The use of a second order polynomial is explained in Appendix F.

The calibration report included with each transducer shows the data from which the linear gage factor and the second order polynomial coefficients are derived. Columns on the right show the size of the error incurred by assuming a linear coefficient and the improvement that can be expected by going to a second order polynomial. In many cases, the difference is minor. The calibration reports give the pressure in certain engineering units. These can be converted to other engineering units using the multiplication factors shown in Table 3 below.

Page 48

From →

↓

psi "H2

"HG

mm HG

atm

mbar

bar

kPa

MPa

psi

.036127

.43275

.0014223

1.4223

.49116

.019337

14.696

.014503

14.5039

.14503

145.03

27.730 1 12

.039372

39.372

13.596

.53525

406.78

.40147

401.47

4.0147

4016.1

2.3108

.08333

.003281

3.281

1.133

.044604

33.8983

.033456

33.4558

.3346

334.6

mm H

704.32

25.399

304.788

1000

345.32

13.595

10332

10.197

10197

101.97

101970

m H

.70432

.025399

.304788

.001

.34532

.013595

10.332

.010197

10.197

.10197

101.97

"HG

2.036

.073552

.882624

.0028959

2.8959

.03937

29.920

.029529

29.529

.2953

295.3

mm HG

51.706

1.8683

22.4196

.073558

73.558

25.4 1 760

.75008

750.08

7.5008

7500.8

atm

.06805

.0024583

.0294996

.0000968

.0968

.03342

.0013158

.0009869

.98692

.009869

9.869

mbar

68.947

2.4908

29.8896

.098068

98.068

33.863

1.3332

1013.2

1000

10000

bar

.068947

.0024908

.0298896

.0000981

.098068

.033863

.001333

1.0132

.001 1 .01

kPa

6.8947

.24908

2.98896

.0098068

9.8068

3.3863

.13332

101.320

100 1 1000

MPa

.006895

.000249

.002988

.00000981

.009807

.003386

.000133

.101320

.0001

.001

O 'H2O mm H20 m H20

Table 3 - Engineering Units Multiplication Factors

Note: Due to changes in specific gravity with temperature, the factors for mercury and water in

Table 3 are approximations.

D.2 Temperature Correction

Careful selection of materials is made in constructing the vibrating wire piezometer to minimize thermal effects; however, most units still have a slight temperature coefficient. Consult the supplied calibration report to obtain the coefficient for a given piezometer.

Since piezometers are normally installed in a tranquil and constant temperature environment, corrections are not normally required. If however, that is not the case for a selected installation, corrections can be made using the internal thermistor for temperature measurement.

Temperature correction equation is as follows:

Temperatur e Correction =

(Current Temperature - Initial Zero Temperature) × Therm al Facto r

PT = (T1-T0) x K

Equation 11 - Temperature Correction

The calculated correction would then be added to the Pressure calculated using Equation 10. (If the engineering units were converted, remember to apply the same conversion to the calculated temperature correction!) For example, assume the initial temperature was 22° C, the current temperature is 15° C, and the thermal coefficient is −.01879 PSI per °C rise. The temperature correction is 0.13 PSI. Adding this to the calculated pressure in the beginning of this appendix results in a temperature corrected pressure of 19.98 PSI.

Page 49

D.3 Barometric Correction (required only on non-vented transducers)

Since the standard piezometer is hermetically sealed and unvented, it responds to changes in atmospheric pressure. That being the case, corrections may be necessary, particularly for the sensitive, low-pressure models. For example, a barometric pressure change from 29 to 31 inches of mercury would result in ≈1 PSI of error (or ≈2.3 feet if monitoring water level in a well!). Thus, it is advisable to read and record the barometric pressure every time the piezometer is read. A separate pressure transducer (piezometer), kept out of the water, may be used for this purpose.

Barometric correction equation is as follows;

Barometric Correctio n =

(Current Barometer - Initial Zero Barometer) × Conversion F actor

PB = (S1-S0) x F

Equation 12 - Barometric Correction

Since barometric pressure is usually recorded in inches of mercury, a Conversion Factor is necessary to convert to PSI. The Conversion Factor for inches of mercury to PSI is .491. Table 3 lists other common Conversion Factors.

The calculated correction is usually subtracted from the Pressure calculated using Equation 10. If the engineering units were converted, remember to apply the same conversion to the calculated barometric correcti on!

The user should be cautioned that this correction scheme assumes ideal conditions. In reality, conditions are not always ideal. For example, if the well is sealed, barometric effects at the piezometer level may be minimal or attenuated from the actual changes at the surface. Thus, errors may result when applying a correction that is not required.

An alternative to making barometric correction is to use piezometers that are vented to the atmosphere.

Equation 13 describes the pressure calculation with temperature and barometric correction applied.

corrected

= ((R1 - R0) x G) + ((T1-T0) x K) - ((S1-S0) x F)

Equation 13 - Corrected Pressure Calculation

Page 50

APPENDIX E. SAMPLE CALIBRATION REPORT

Figure 36 - Vibrating Wire Pressure Transducer Calibration Report

Page 51

APPENDIX F. IMPROVING THE ACCUR ACY OF CALCULATED PRESSURES

Most vibrating wire pressure transducers are sufficiently linear (± 0.2 % FS) that use of the linear calibration factor satisfies normal requirements. However, it should be noted that the accuracy of the calibration data, which is dictated by the accuracy of the calibration apparatus, is always ±

0.1 % FS.

This level of accuracy can be recaptured, even where the transducer is non-linear, by the use of a second order polynomial expression, which gives a better fit to the data then does a straight line.

The polynomial expression has the form:

Pressure = AR2 + BR + C

Equation 14 - Second Order Polynomial Expression

Where; R is the reading (digits) A, B, and C, are coefficients

Figure 36 shows a calibration report of a transducer that has a comparatively high non-linearity. The figure under the “Linearity (%FS)” column is:

1-R0

F.S.

)

-P x 100%

Calculated Pressure-True Pressure

G(R

x 100%=

Full Scale Pressure

Equation 15 - Linearity Calc ulation

For example when P= 40 psi, G (R0 - R1) gives a calculated pressure of 39.642 psi. The error is

0.357 psi or as much as 9.9 inches of water!

Whereas the polynomial expression gives a calculated pressure of A (7773)2 + B (7773) + C =

39.996 psi and the actual error is only 0.004 psi or 0.1 inch of water.

Note: If the polynomial equation is used, it is important that the value of C, in the polynomial equation, be taken in the field. The field value of C is calculated by inserting the initial zero reading into the polynomial equation with the pressure, P, set to zero. As of 8/2011, Geokon no longer includes the C coefficient on its calibration reports, ensuring that, to properly use the polynomial equation, users must calculate a C coefficient.

It should be noted that where changes of water levels are being monitored it makes little difference whether the linear coefficient or the polynomial expression is used.

Page 52

APPENDIX G. BAROMETRIC CORRECTI O N ( NO N-VENTED TRANSDUCERS ONLY)

Since the standard piezometer is hermetically sealed and unvented, it responds to changes in atmospheric pressure. That being the case, corrections may be necessary, particularly for the sensitive, low-pressure models. The digits for the range of the transducer, as shown on the calibration report, may vary considerably with changes in elevation (offset). It is a simple matter to compensate for this offset with the 8020-59.

Referring to the example calibration report (Appendix E, Figure 36), note that the average zero reading (0 psi) is 9139 digits (8020-59 maximum digits) and the average maximum reading (100 psi) is 5691 digits (8020-59 minimum digits). These readings were recorded at an atmospheric pressure of 1001.4 mbar, corresponding to the conditions and altitude at the Geokon factory. To compensate for elevation change, take a new zero reading at the site location. This new zero reading becomes the maximum digits entered into the 8020-59. Add the difference between the new zero reading and the original zero reading to the maximum reading shown on the calibration report. This becomes the new minimum digits entered into the 8020-59.

For example:

0 psi Average Reading 100 psi Average Reading

Calibration Report: 9139 5691

Site Location: 9950 (+811 digits) 6502

(new maximum digits) (new minimum digits)

Geokon 8020-59 Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1. INTRODUCTION

2. INSTALLING AND CONFIGURING THE 8 0 20-59 SOFTWARE APPLICATION

2.1 Configuring the COM Port

3. QUICK START (SINGLE CHANNEL)

4. SINGLE AND MULTI-CHANNEL OPERATION

4.1 Theory of Operation

4.2 Operating Modes

4.2.1 Single Channel Mode

4.2.2 16-Channel Multiplexed Mode

4.2.3 32-Channel Multiplexed Mode

4.3 Conversion to “Digits”

4.4 Connection to a Voltage Input DAS

4.5 Connection to a Current Input DAS

4.6 Temperature Measurement

5. COMMUNICATIONS

5.1 Command Line Interface

6. 8020-59 WINDOWS APPLICATION

6.1 Software Installation

6.2 Starting the 8020-59 Application

6.3 Communications Timeout Error

6.4 Single Channel Configuration

6.5 16-Channel Configuration

6.6 32-Channel Configuration

APPENDIX A. SPECIFICATIONS

A.1 8020-59 Specifications

A.2 Multiplexer Timing Specifications

APPENDIX B. THERMISTOR TEMPERATURE DERIVATION

APPENDIX C. WIRING CONFI G URATIONS

C.1 Voltage Output – Single Channel Mode (Digital I/O DAS)

C.2 Voltage Output – 16-Channel Mode (Digital I/O DAS)

C.3 Voltage Output – 32-Channel Mode (Digital I/O DAS)

C.4 Current Output – Single Channel Mode (Digital I/O DAS)

C.5 Current Output – 16-Channel Mode (Digital I/O DAS):

C.6 Current Output – 32-Channel Mode (Digital DAS)

C.7 Voltage Output – Single Channel Mode (PLC DAS)

C.8 Voltage Output – 16-Channel Mode (PLC DAS)

C.9 Voltage Output – 32-Channel Mode (PLC DAS)

C.10 Current Output – Single Channel Mode (PLC DAS)

C.11 Current Output – 16-Channel Mode (PLC DAS)

C.12 Current Output – 32-Channel Mode (PLC DAS)

APPENDIX D. DATA REDUCTION

D.1 Pressure Calculation

D.2 Temperature Correction

D.3 Barometric Correction (required only on non-vented transducers)

APPENDIX E. SAMPLE CALIBRATION REPORT

APPENDIX F. IMPROVING THE ACCUR ACY OF CALCULATED PRESSURES

APPENDIX G. BAROMETRIC CORRECTI O N ( NO N-VENTED TRANSDUCERS ONLY)