Tektronix DAS-TC/B Users Guide

DAS-TC/B

User’s Guide

A GREATER MEASURE OF CONFIDENCE

WARRANTY

Hardware

Keithley Instruments, Inc. warrants that, for a period of one (1) year from the date of shipment (3 years for Models 2000,
2001, 2002, 2010 and 2700), the Keithley Hardware product will be free from defects in materials or workmanship. This
warranty will be honored provided the defect has not been caused by use of the Keithley Hardware not in accordance with
the instructions for the product. This warranty shall be null and void upon: (1) any modification of Keithley Hardware that
is made by other than Keithley and not approved in writing by Keithley or (2) operation of the Keithley Hardware outside
of the environmental specifications therefore.

Upon receiving notification of a defect in the Keithley Hardware during the warranty period, Keithley will, at its option,
either repair or replace such Keithley Hardware. During the first ninety days of the warranty period, Keithley will, at its
option, supply the necessary on site labor to return the product to the condition prior to the notification of a defect. Failure
to notify Keithley of a defect during the warranty shall relieve Keithley of its obligations and liabilities under this
warranty.

Other Hardware

The portion of the product that is not manufactured by Keithley (Other Hardware) shall not be covered by this warranty,
and Keithley shall have no duty of obligation to enforce any manufacturers' warranties on behalf of the customer. On those
other manufacturers’ products that Keithley purchases for resale, Keithley shall have no duty of obligation to enforce any
manufacturers’ warranties on behalf of the customer.

Software

Keithley warrants that for a period of one (1) year from date of shipment, the Keithley produced portion of the software or
firmware (Keithley Software) will conform in all material respects with the published specifications provided such Keithley
Software is used on the product for which it is intended and otherwise in accordance with the instructions therefore.
Keithley does not warrant that operation of the Keithley Software will be uninterrupted or error-free and/or that the Keithley
Software will be adequate for the customer's intended application and/or use. This warranty shall be null and void upon any
modification of the Keithley Software that is made by other than Keithley and not approved in writing by Keithley.

If Keithley receives notification of a Keithley Software nonconformity that is covered by this warranty during the warranty
period, Keithley will review the conditions described in such notice. Such notice must state the published specification(s)
to which the Keithley Software fails to conform and the manner in which the Keithley Software fails to conform to such
published specification(s) with sufficient specificity to permit Keithley to correct such nonconformity. If Keithley deter­mines that the Keithley Software does not conform with the published specifications, Keithley will, at its option, provide
either the programming services necessary to correct such nonconformity or develop a program change to bypass such
nonconformity in the Keithley Software. Failure to notify Keithley of a nonconformity during the warranty shall relieve
Keithley of its obligations and liabilities under this warranty.

Other Software

OEM software that is not produced by Keithley (Other Software) shall not be covered by this warranty, and Keithley shall
have no duty or obligation to enforce any OEM's warranties on behalf of the customer.

Other Items

Keithley warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes,
and documentation.

Items not Covered under Warranty

This warranty does not apply to fuses, non-rechargeable batteries, damage from battery leakage, or problems arising from
normal wear or failure to follow instructions.

Limitation of Warranty

This warranty does not apply to defects resulting from product modification made by Purchaser without Keithley's express
written consent, or by misuse of any product or part.

Disclaimer of Warranties

EXCEPT FOR THE EXPRESS WARRANTIES ABOVE KEITHLEY DISCLAIMS ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION, ALL IMPLIED WARRANTIES OF MERCHANT­ABILITY AND FITNESS FOR A PARTICULAR PURPOSE. KEITHLEY DISCLAIMS ALL WARRANTIES WITH
RESPECT TO THE OTHER HARDWARE AND OTHER SOFTWARE.

Limitation of Liability

KEITHLEY INSTRUMENTS SHALL IN NO EVENT, REGARDLESS OF CAUSE, ASSUME RESPONSIBILITY FOR
OR BE LIABLE FOR: (1) ECONOMICAL, INCIDENTAL, CONSEQUENTIAL, INDIRECT, SPECIAL, PUNITIVE OR
EXEMPLARY DAMAGES, WHETHER CLAIMED UNDER CONTRACT, TORT OR ANY OTHER LEGAL THEORY,
(2) LOSS OF OR DAMAGE TO THE CUSTOMER'S DATA OR PROGRAMMING, OR (3) PENALTIES OR PENALTY
CLAUSES OF ANY DESCRIPTION OR INDEMNIFICATION OF THE CUSTOMER OR OTHERS FOR COSTS, DAM­AGES, OR EXPENSES RELATED TO THE GOODS OR SERVICES PROVIDED UNDER THIS WARRANTY.

Keithley Instruments, Inc.

Sales Offices: BELGIUM: Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02-363 00 40 • Fax: [phone]

CHINA: Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-6202-2886 • Fax: [phone]
FINLAND: Tietäjäntie 2 • 02130 Espoo • Phone: [phone] • Fax: [phone]
FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: [phone]
GERMANY: Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: [phone]
GREAT BRITAIN: Unit 2 Commerce Park, Brunel Road • Theale • Berkshire RG7 4AB • 0118 929 7500 • Fax: [phone]
INDIA: Flat 2B, Willocrissa • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: [phone]
ITALY: Viale San Gimignano, 38 • 20146 Milano • 02-48 39 16 01 • Fax: [phone]
JAPAN: New Pier Takeshiba North Tower 13F • 11-1, Kaigan 1-chome • Minato-ku, Tokyo 105-0022 • 81-3-5733-7555 • Fax: [phone]
KOREA: 2FL., URI Building • 2-14 Yangjae-Dong • Seocho-Gu, Seoul 137-888 • 82-2-574-7778 • Fax: [phone]
NETHERLANDS: Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
SWEDEN: c/o Regus Business Centre • Frosundaviks Allé 15, 4tr • 169 70 Solna • 08-509 04 679 • Fax: [phone]
SWITZERLAND: Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: [phone]
TAIWAN: 1FL., 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3-572-9077• Fax: [phone]

28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: [phone]

1-888-KEITHLEY (534-8453) • www.keithley.com

4/02

DAS-TC/B User’s Guide

Revision C - June 2002

Part Number: 95630

Basic™ is a trademark of Dartmouth College.

IBM® is a registered trademark of International Business Machines Corporation.

PC, XT, and AT® are trademarks of International Business Machines Corporation.

Microsoft® is a registered trademark of Microsoft Corporation.

Turbo C® is a registered trademark of Borland International.

DriverLINX is a registered trademark of Scientific Software Tools, Inc.

All other brand and product names are trademarks or registered trademarks of their
respective companies.

Information furnished by Keithley Instruments is believed to be accurate and reliable.
However, Keithley Instruments assumes no responsibility for the use of such information nor
for any infringements of patents or other rights of third parties that may result from its
use. No license is granted by implication or otherwise under any patent rights of Keithley

Instruments.

WARNING

Keithley Instruments assumes no responsibility for damages consequent to

the use of this product. This product is not designed with components of a level of

reliability suitable for use in life support or critical applications.

S

The following safety precautions should be observed before using this product and any associated instrumentation.
Although some instruments and accessories would normally be used with non-hazardous voltages, there are situations
where hazardous conditions may be present.

This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety
precautions required to avoid possible injury. Read and follow all installation, operation, and maintenance information
carefully before using the product. Refer to the manual for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product may be impaired.

The types of product users are:

Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that

the equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately
trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use

of the instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting

the line voltage or replacing consumable materials. Maintenance procedures are described in the manual. The proce­dures explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, and perform safe installations and repairs of products. Only

properly trained service personnel may perform installation and service procedures.

Keithley products are designed for use with electrical signals that are rated Installation Category I and Installation
Category II, as described in the International Electrotechnical Commission (IEC) Standard IEC 60664. Most mea­surement, control, and data I/O signals are Installation Category I and must not be directly connected to mains voltage
or to voltage sources with high transient over-voltages. Installation Category II connections require protection for high
transient over-voltages often associated with local AC mains connections. Assume all measurement, control, and data
I/O connections are for connection to Category I sources unless otherwise marked or described in the Manual.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or
test fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels
greater than 30V RMS, 42.4V peak, or 60VDC are present.

age is present in any unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that
operators are prevented access and/or insulated from every connection point. In some cases, connections must be ex­posed to potential human contact. Product operators in these circumstances must be trained to protect themselves from
the risk of electric shock. If the circuit is capable of operating at or above 1000 volts,

may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance
limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards,
install protective devices to limit fault current and voltage to the card.

Before operating an instrument, make sure the line cord is connected to a properly grounded power receptacle. Inspect
the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

afety Precautions

A good safety practice is to expect that hazardous volt-

no conductive part of the circuit

5/02

When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main
input power disconnect device must be provided, in close proximity to the equipment and within easy reach of the
operator.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the cir­cuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting
or disconnecting cables or jumpers, installing or removing switching cards, or making internal changes, such as in­stalling or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth)
ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the
voltage being measured.

The instrument and accessories must be used in accordance with its specifications and operating instructions or the
safety of the equipment may be impaired.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and op­erating information, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with same type and rating for continued protection against fire hazard.

Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth ground con­nections.

If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation re­quires the use of a lid interlock.

If or is present, connect it to safety earth ground using the wire recommended in the user documentation.

!

The symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.

The symbol on an instrument shows that it can source or measure 1000 volts or more, including the combined
effect of normal and common mode voltages. Use standard safety precautions to avoid personal contact with these
voltages.

The

WARNING

associated information very carefully before performing the indicated procedure.

The

CAUTION

the warranty.

Instrumentation and accessories shall not be connected to humans.

Before performing any maintenance, disconnect the line cord and all test cables.

To maintain protection from electric shock and fire, replacement components in mains circuits, including the power
transformer, test leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses, with applicable
national safety approvals, may be used if the rating and type are the same. Other components that are not safety related
may be purchased from other suppliers as long as they are equivalent to the original component. (Note that selected parts
should be purchased only through Keithley Instruments to maintain accuracy and functionality of the product.) If you
are unsure about the applicability of a replacement component, call a Keithley Instruments office for information.

To clean an instrument, use a damp cloth or mild, water based cleaner. Clean the exterior of the instrument only. Do
not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist
of a circuit board with no case or chassis (e.g., data acquisition board for installation into a computer) should never
require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected,
the board should be returned to the factory for proper cleaning/servicing.

heading in a manual explains dangers that might result in personal injury or death. Always read the

heading in a manual explains hazards that could damage the instrument. Such damage may invalidate

Table of Contents

Preface

1

Overview

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Supporting Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

DriverLINX Driver Software for Windows 95/98/NT . . . . . .1-2

TestPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

LabVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

2

Functional Description

Control Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

Operational Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

3

Installation

Inventorying Required Installation Resources. . . . . . . . . . . . . . .3-1

Installing the Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Installing Application Software and Drivers. . . . . . . . . . . . . . 3-2

Installing the TestPoint software and driver. . . . . . . . . . . . 3-2

Installing the LabVIEW Software and Driver . . . . . . . . . .3-3

Installing DriverLINX Software Components and

Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

DriverLINX Installation Options . . . . . . . . . . . . . . . . . . . . 3-4

DriverLINX Installation Procedure . . . . . . . . . . . . . . . . . . 3-4

Configuring Your Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Preparing and Installing Your Board . . . . . . . . . . . . . . . . . . . . . . 3-8

Unwrapping and Inspecting Your Board . . . . . . . . . . . . . . . . . 3-8

Setting the Base Address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

Installing the Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10

Checking Your Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

ix

4

Cabling and Wiring

Using Screw Terminal Accessories . . . . . . . . . . . . . . . . . . . . . . . 4-1

Features of Screw Terminal Accessories. . . . . . . . . . . . . . . . . 4-2

Cold Junction Compensation (CJC) Temperature Sensor . 4-4

Open-Thermocouple Detection Signals . . . . . . . . . . . . . . . 4-5

Ground Terminals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Connecting an STC-TC/B. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Connecting an STA-TC/B. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Connecting Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7

Understanding the DAS-TC/B Inputs. . . . . . . . . . . . . . . . . . . 4-8

Connecting an Ungrounded Thermocouple . . . . . . . . . . . 4-10

Connecting a Grounded Thermocouple . . . . . . . . . . . . . . 4-12

Connecting Other Signal Sources . . . . . . . . . . . . . . . . . . . . .4-13

Connecting a Floating Signal Source. . . . . . . . . . . . . . . . 4-13

Connecting a Grounded Signal Source . . . . . . . . . . . . . . 4-14

5

The DAS-TC/B Data Logger

Features of the DAS-TC/B Data Logger . . . . . . . . . . . . . . . . . . . 5-1

Starting the DAS-TC/B Data Logger. . . . . . . . . . . . . . . . . . . . . . 5-2

Using the DAS-TC/B Data Logger . . . . . . . . . . . . . . . . . . . . . . . 5-2

6

Calibration

7

Troubleshooting

Problem Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Testing the Board and Host Computer . . . . . . . . . . . . . . . . . . 7-3

Testing the Accessory Slot and I/O Connections . . . . . . . . . . 7-4

Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-5

A

Specifications

B

Connector Pin Assignments

C

CE Information
for the DAS-TC/B

Limitation of Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

Declaration of Conformity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

Cabling Instructions for the CE Configuration . . . . . . . . . . . . . C-3

x

List of Illustrations

Figure 2-1. Block Diagram of DAS-TC/B . . . . . . . . . . . . . . . . 2-2

Figure 3-1. Base Address Switch . . . . . . . . . . . . . . . . . . . . . .3-10

Figure 4-1. STC-TC/B Layout . . . . . . . . . . . . . . . . . . . . . . . . .4-2

Figure 4-2. STA-TC/B Layout. . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Figure 4-3. Schematic for CJC Temperature Sensor Circuit . . 4-4

Figure 4-4. Attaching an STC-TC/B to a DAS-TC/B . . . . . . .4-7

Figure 4-5. Attaching an STA-TC/B to a DAS-TC/B . . . . . . .4-7

Figure 4-6. DAS-TC/B Inputs . . . . . . . . . . . . . . . . . . . . . . . . .4-8

Figure 4-7. Connecting an Ungrounded Thermocouple. . . . .4-11

Figure 4-8. Connecting a Grounded Thermocouple. . . . . . . .4-12

Figure 4-9. Connecting a Floating Signal Source,

Method 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-13

Figure 4-10. Connecting a Floating Signal Source,

Method 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-14

Figure 4-11. Connecting a Grounded Signal Source . . . . . . . .4-15

Figure 6-1. Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

Figure B-1. Pin Assignments for DAS-TC/B

Main I/O Connector. . . . . . . . . . . . . . . . . . . . . . . B-1

Figure C-1. Connecting a DAS-TC/B Board

to an STC-TC/B. . . . . . . . . . . . . . . . . . . . . . . . . . C-3

Figure C-2. Connecting a DAS-TC/B Board

to an STA-TC/B. . . . . . . . . . . . . . . . . . . . . . . . . . C-3

xi

List of Tables

Table 7-1. Troubleshooting Information. . . . . . . . . . . . . . . . .7-1

Table A-1. Analog Input Specifications . . . . . . . . . . . . . . . . A-1

Table A-2. Conversion Rate Specifications. . . . . . . . . . . . . . A-2

Table A-3. Temperature/Voltage Specifications . . . . . . . . . . A-2

Table A-4. Voltage Input Specifications . . . . . . . . . . . . . . . . A-2

Table A-5. Thermocouple Input Specifications. . . . . . . . . . . A-3

Table A-6. Noise Specifications . . . . . . . . . . . . . . . . . . . . . . A-3

Table A-7. Maximum Gain Error Temperature Coefficients A-4

Table A-8. Environmental and Physical Requirements. . . . . A-4

Table A-9. Power Requirements . . . . . . . . . . . . . . . . . . . . . . A-4

Table A-10. Board Requirements . . . . . . . . . . . . . . . . . . . . . . A-5

xii

Preface

The

DAS-TC/B User’s Guide

handling and using a DAS-TC/B thermocouple/voltage measuring board.
To follow the information and instructions contained in this manual, you
must be familiar with data-acquisition principles, with your application,
and with the Windows
computers. This product works best with a computer having a
Pentium-series processor.

The

DAS-TC/B User’s Guide

• Section 1 describes board features, software, and accessories.

• Section 2 describes operating features of a board in more detail. This
section contains a block diagram and brief descriptions of the features
as they relate to your options for setting up and using a board.

• Section 3 contains instructions for inspection, software installation,
configuration, and board installation.

contains information and instructions for

®

95/98/NT operating system and compatible

is organized as follows:

• Section 4 shows the preferred methods of making I/O (Input/Output)
connections, using the available accessories and cables.

• Section 5 summarizes the features of the DriverLINX DAS-TC/B
Data Logger program, how to start the program, how to access
detailed information, and instructions.

• Section 6 describes calibration requirements.

• Section 7 contains information on troubleshooting and on obtaining
technical support.

xiii

• Appendix A contains specifications.

• Appendix B contains pin assignments for the main I/O connector.

• Appendix C contains CE mark certification.

• The index provides hyperlinks, as well as written page numbers, to
locate various subjects in the manual.

xiv

Features

1

Overview

The DAS-TC/B is a thermocouple/voltage measuring board that accepts
up to 16 inputs. You can configure input channels individually to accept
inputs from thermocouples or other voltage sources. Channels configured
for thermocouple inputs provide readings in degrees (Celsius or
Fahrenheit), while channels configured for voltage inputs provide
readings in volts.

This section describes the DAS-TC/B features, software, and accessories.

DAS-TC/B features are as follows:

The board fits an accessory slot of a computer.

●

●

All 16 channels are differential inputs.

●

Thermocouple inputs can be any mix of up to seven standard types, as
follows: B, E,

●

Thermocouple measurements are linearized by an onboard
microprocessor for readings in degrees.

Open-thermocouple detection is selectable.

●

●

Automatic CJC (cold-junction compensation) is performed on a
per-channel-basis and is continuous.

Calibration of the CJC and board logging parameters is automatic and

●

continuous.

●

Inputs to the DAS-TC/B enter through either a plug-in screw-terminal
block (the STC-TC/B) or an external screw-terminal box (the
STA-TC/B).

Features 1-1

J, K, R, S, and T.

CMRR (Common Mode Rejection Ratio) is greater than 100dB for

●

gains greater than one.

●

The rejection rate is configurable for 50, 60, or 400Hz.
Analog inputs (measurement section) are electrically isolated from

●

the PC.

●

The board can perform onboard averaging.

Supporting Software

Available software allows you to take two different approaches to
configuring and running your DAS-TC/B board. You can use a fully
integrated data acquisition software package (TestPoint or LabVIEW) or
write a custom program in Visual C/C++, Visual Basic, or Delphi using
DriverLINX (included with the hardware). A summary of the pros and
cons of using integrated packages or writing custom programs is provided
in the Keithley Full Line Catalog. The DAS-TC/B has fully functional
driver support for use under Windows 95/98/NT.

Note:

DriverLINX must be installed to run any applications for the
board, whether they are custom-programmed applications or integrated
software packages, such as TestPoint or LabVIEW.

The characteristics of DriverLINX, TestPoint, and LabVIEW are
summarized below.

DriverLINX Driver Software for Windows 95/98/NT

DriverLINX software, supplied by Keithley with the DAS-TC/B board,
provides convenient interfaces to configure and set I/O bits without
register-level programming.

Most importantly, however, DriverLINX supports those programmers
who want to create custom applications using Visual C/C++, Visual
Basic, or Delphi. DriverLINX accomplishes foreground and background

1-2 Overview

tasks to perform data acquisition. The software includes memory and data
buffer management, event triggering, extensive error checking, and
context sensitive online help.

More specifically, DriverLINX provides application developers a
standardized interface to over 100 services for creating foreground and
background tasks for the following:

Analog input and output

●

●

Digital input and output

●

Time and frequency measurement
Event counting

●

●

Pulse output

●

Period measurement

In addition to basic I/O support, DriverLINX also provides:

●

Built-in capabilities to handle memory and data buffer management

●

A selection of starting and stopping trigger events, including
pre-triggering, mid-point triggering, and post-triggering protocols

●

Extensive error checking

●

Context-sensitive on-line help system

DriverLINX is essentially hardware independent; its portable APIs work
across various operating systems. This capability eliminates unnecessary
programming when changing operating system platforms.

TestPoint

TestPoint is a fully featured, integrated application package that
incorporates many commonly used math, analysis, report generation, and
graphics functions. TestPoint’s graphical drag-and-drop interface can be
used to create data acquisition applications, without programming, for
IEEE-488 instruments, data acquisition boards, and RS232-485
instruments and devices.

Supporting Software 1-3

LabVIEW

Accessories

TestPoint includes features for controlling external devices, responding to
events, processing data, creating report files, and exchanging information
with other Windows programs. It provides libraries for controlling most
popular GPIB instruments. OCX and ActiveX controls plug directly into
TestPoint, allowing additional features from third party suppliers.

LabVIEW is a fully featured, graphical programming language used to
create virtual instrumentation. It consists of an interactive user interface,
complete with knobs, slides, switches, graphs, strip charts, and other
instrument panel controls. Its data driven environment uses function
blocks that are virtually wired together and pass data to each other. The
function blocks, which are selected from palette menus, range from
arithmetic functions to advanced acquisition, control, and analysis
routines. Also included are debugging tools, help windows, execution
highlighting, single stepping, probes, and breakpoints to trace and
monitor the data flow execution. LabVIEW can be used to create
professional applications with minimal programming.

The following accessories are available for the DAS-TC/B:

●

STC-TC/B

— a panel containing a CJC sensor and screw terminals
for all DAS-TC/B I/O connections. The STC-TC/B plugs directly into
the main I/O connector of the DAS-TC/B and extends from the rear
of the computer.

STA-TC/B

●

— contains a CJC sensor and screw terminals for all
DAS-TC/B I/O connections. Use a C-1800 cable to connect the
STA-TC/B to the DAS-TC/B.

●

C-1800

— an 18-inch ribbon cable for connecting the STA-TC/B to
the DAS-TC/B. This cable is available in longer lengths that must be
specified in the part number (for example, to specify three extra feet
use C-1803).

S-1800

●

1-4 Overview

— a shielded version of the C-1800 cable.

2

Functional Description

This section describes the operating features of the DAS-TC/B.

The DAS-TC/B consists of two sections: the isolated input section and
the control section. The isolated input section handles the measurement
functions, while the control section handles data processing. Figure 2-1 is
a block diagram of the two sections and their stages.

2-1

V/F

Converter

Opto-

Isolator

Logic

Decode

Address

Inst.

Amp.

Input

Channel

Mux

Opto-

Isolator

Mux

Gain

Opto-

Isolator

Xtal

16MHz

CPU

Control

Clock

4MHz

Register

Ref.

Input

Voltage

Opto-

Mux

Pulse

CPU

Isolator

Signal

Conditioning

+10V

Voltage

Precision

PC I/O

Control

Decode and

Reference

Logic

Control

Interrupt

RAM

Static

Dual-Port

RAM

Static

ROM

Control

Section

Section

Isolated Input

PC Bus

Figure 2-1. Block Diagram of DAS-TC/B

−15V

CH00

Input

Channels

Differential

CH15

00 to 15

CJC Input

Ref.

+9.9V

+15V

+5V

Power

Supply

DC/DC

2-2 Functional Description

Isolated Input Section

The isolated input section consists of a 16-channel input multiplexer, a
CJC sensor input, calibration inputs, a programmable gain amplifier, and
a V/F (voltage-to-frequency) converter. During operation, the DAS-TC/B
constantly monitors and uses the CJC input to maintain the accuracy of
the board. At the same time, the board switches in a precision 9.9V input
to measure gain error at a gain of 1 and to measure offset errors for all
four gain ranges. The board then stores these measurements in onboard
memory.

The four ranges of the programmable gain amplifier are selectable to
match the thermocouple input ranges and to accommodate the voltage
input range of

The V/F converter provides excellent noise rejection and high resolution,
while generating a pulsed output whose frequency is proportional to the
voltage input. The pulsed output passes first through a stage of optical
isolation and then into a stage of counting, where a count of the square
waves over a specified period determines a value for the corresponding
voltage input. The period for each count of square waves is set by the
value entered in the configuration file for Normal Mode Rejection
Frequency (50, 60, or 400 samples/s); the actual period is one-half this
selected value. The longer the count time, the higher the resolution and
better the noise rejection.

−

2.5V to 10V (using a gain of 1).

Control Section

The control section consists of the microprocessor and its memory. The
microprocessor performs all control functions and mathematical calcula­tions, precluding the need for any computer processing. Working from the
configuration file, the microprocessor sets up the board for the desired
configuration. Board parameters include interrupt level and Normal Mode
Rejection Frequency. Channel parameters include thermocouple type,
number of samples to average, and type of engineering units. During the
acquisition process, the microprocessor also handles scan order, thermo­couple linearization, and calculations for CJC.

Control Section 2-3

Onboard memory includes ROM, Static RAM, and Dual-Port Static
RAM. ROM contains the DAS-TC/B control program, which directs the
activities of the microprocessor and the thermocouple look-up tables.
Static RAM serves as the CPU “scratch pad,” providing temporary
storage for measurement results and calibration coefficients. The
dual-port RAM is the buffer for communications and data flow to/from
the computer.

Operational Flow

Configuration data for the DAS-TC/B board and channels is contained in
a configuration file. The configuration file is generated through
DriverLINX.

During DAS-TC/B initialization, the CPU downloads configuration infor­mation from the computer hard drive to the DAS-TC/B board memory.
The CPU then sets up the DAS-TC/B board and channel parameters to the
specified values. Following parameter setup, the CPU performs a calibra­tion and stores the gain and offset coefficients in board memory. Next, the
board reads and stores the CJC sensor value.

When the PC initiates a channel scan, the DAS-TC/B scans the channels
in the order specified by the PC. Channels designated for thermocouple
input use parameter values from the configuration file. Channels desig­nated for voltage input also use parameter values from the configuration
file, unless you overwrite these values.

Channel readings proceed at less than the rate specified by the value for
Normal Mode Rejection Frequency in the configuration file. The reading
for each channel requires a count of the frequency output of the V/F con­verter. The CPU compensates for calibration errors in these readings. For
channels configured as thermocouple inputs, the CPU also adjusts for
CJC and converts the readings to temperature measurements. For chan­nels configured as voltage inputs, the CPU converts the readings to volts.

2-4 Functional Description

To convert thermocouple readings to temperature measurements, the CPU
refers to look-up tables, stored in ROM. A separate look-up table is avail­able for each thermocouple type accommodated by the DAS-TC/B. The
look-up tables optimize accuracy by using more reference points along
ranges of greatest temperature-versus-voltage change than along ranges
of minimal change. (Using the same number of points at fixed intervals
would lead to error along ranges of greatest temperature-versus-voltage
change.)

As soon as all readings and conversions are complete, the DAS-TC/B
requests an interrupt and transfers all measurements to the computer.

The DAS-TC/B makes periodic measurements of the CJC and performs
self-calibration as a background task.

Operational Flow 2-5