Tektronix DAS-1800ST,DAS-1800HR Series Users Guide

DAS-1800ST/HR Series

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-1800ST/HR Series

User’s Guide

Revision H - June 2002

Part Number: 90090

The information contained in this manual is believed to be accurate and reliable. However, the
manufacturer assumes no responsibility for its use; 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 the manufacturer.

THE MANUFACTURER SHALL NOT BE LIABLE FOR ANY SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES RELATED TO THE USE OF THIS PRODUCT. THIS PRODUCT IS
NOT DESIGNED WITH COMPONENTS OF A LEVEL OF RELIABILITY THAT IS SUITED FOR
USE IN LIFE SUPPORT OR CRITICAL APPLICATIONS.

DriverLINX, SSTNET, and LabOBJX are registered trademarks and DriverLINX/VB is a trademark of
Scientific Software Tools, Inc.

Microsoft and Windows are registered trademarks and Visual C++ and Visual Basic are trademarks of
Microsoft Corporation.

Borland is a registered trademark and Borland C++, Delphi, and Turbo Pascal are trademarks of
Borland International, Inc.

IBM is a registered trademark of International Business Machines Corporation.

Acrobat is a registered trademark of Adobe Systems Incorporated.

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

Copyright © Keithley Instruments, Inc., 1999, 1996, 1995, 1994.

All rights reserved. Reproduction or adaptation of any part of this documentation beyond that permitted
by Section 117 of the 1979 United States Copyright Act without permission of the Copyright owner is
unlawful.

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

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

Operators

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

Maintenance personnel

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

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.

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

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

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

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

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

Supporting Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

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

2

Functional Description

Analog Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

Differential/Single-Ended Selection . . . . . . . . . . . . . . . . . . . .2-5

Low-Side Reference Selection for Single-Ended Inputs . . . .2-6

Unipolar/Bipolar Selection . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

Channel-Gain Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

Channel Expansion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Multiplexer Control Lines MUX 4 to MUX 7 . . . . . . . 2-8

External Gain Control Line GEXT . . . . . . . . . . . . . . . .2-8

Gains and Ranges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

Maximum Achievable Throughput Rates. . . . . . . . . . . . . .2-9

Data Conversion Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

Clock Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

Pacer Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

Burst Mode Conversion Clock. . . . . . . . . . . . . . . . . . . . .2-17

Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18

Pre-Trigger Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . .2-20

About-Trigger Acquisition . . . . . . . . . . . . . . . . . . . . . . . . 2-20

Post-Trigger Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

Data Transfer Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

Analog Output Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

DAS-1800ST-DA Series Boards . . . . . . . . . . . . . . . . . . . . . . 2-23

DAS-1802HR-DA Boards. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Digital I/O Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Using Digital Control Signal DOSTB . . . . . . . . . . . . . . . . .2-24

Using Digital Control Signal TGOUT . . . . . . . . . . . . . . . . . 2-24

Using Digital Control Signal SSHO . . . . . . . . . . . . . . . . . . .2-26

Assigning an Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-28

iii

3

Setup and Installation

Unwrapping and Inspecting Your Board . . . . . . . . . . . . . . . . . . . 3-1

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

Installing the DAS-1800ST/HR Series Standard Software

Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2

Before Installing DriverLINX . . . . . . . . . . . . . . . . . . . . . .3-2

Selecting the DriverLINX components to Install. . . . . . . . 3-3

Installing DriverLINX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Setting the Base Address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Installing the Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6

Configuring the DAS-1800ST/HR Board with DriverLINX . . . . 3-6

4

Cabling and Wiring

Attaching an STA-1800U. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Attaching an STP-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Attaching SSH-8 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Attaching an MB01 Backplane . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Attaching MB02 Backplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Attaching EXP-1800 Expansion Accessories . . . . . . . . . . . . . . 4-10

Connecting Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-11

Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11

Precautions for Using a DAS-1801ST Board

at High Gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Additional Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Connecting a Signal to a Single-Ended Analog Input. . . . . .4-13

Connecting a Signal to a Differential Analog Input . . . . . . .4-14

Avoiding a Ground Loop Problem . . . . . . . . . . . . . . . . . . . . 4-15

Connecting Analog Output Signals. . . . . . . . . . . . . . . . . . . . 4-16

Connecting Digital I/O Signals. . . . . . . . . . . . . . . . . . . . . . . 4-17

Connecting Digital Control Signals . . . . . . . . . . . . . . . . . . . 4-17

Connecting and Synchronizing Multiple Boards . . . . . . . . . 4-18

5

Testing the Board

DriverLINX Analog I/O Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Test Panel Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2

6

Calibration

Equipment Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

Potentiometers and Test Points . . . . . . . . . . . . . . . . . . . . . . . . . .6-2

DriverLINX Calibration Utility . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4

iv

7

Troubleshooting

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

Using the DriverLINX Event Viewer . . . . . . . . . . . . . . . . . . .7-1

Device Initialization Error Messages . . . . . . . . . . . . . . . . . . . 7-2

Identifying Symptoms and Possible Causes . . . . . . . . . . . . . .7-2

Testing the Board and Host Computer . . . . . . . . . . . . . . . . . . 7-5

Testing the Accessory Slot and I/O Connections . . . . . . . . . . 7-6

Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

A

Specifications

B

Connector Pin Assignments

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

I/O Connectors J1 and J2 of the STA-1800U Accessory. . . . . . B-2

Connector J3 of the STA-1800U Accessory . . . . . . . . . . . . . . . B-3

Connectors J4 to J7 and Jumper Pads J8 to J11 of the STA-1800U

Accessory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

C

DriverLINX Configuration Notes

Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

Calibrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

A/D Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

A/D Volts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

D/A Volts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

AI IRQ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

AI DMA 1, AO DMA 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

Special Device Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

Common-mode reference . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

Number of EXP-1800s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-5

Simultaneous sample and hold configuration . . . . . . . . . . . . C-5

Disable AO recycle mode . . . . . . . . . . . . . . . . . . . . . . . . . . . C-5

Implementation Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-6

v

Analog Input Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-8

Analog Input Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . C-8

Internal Clocking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-9

Burst Mode Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-9

Repeat Mode Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-9

External Clocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-9

External Triggering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-10

External Gating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-10

Simultaneous Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . C-10

Analog Input Multiplexer . . . . . . . . . . . . . . . . . . . . . . . . . . C-11

Data Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-13

A/D Conversion Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-15

A/D Data Lost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-15

Analog Output Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-16

Analog Output Initialization . . . . . . . . . . . . . . . . . . . . . . . . C-17

Internal Clocking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-17

Synchronous Analog Input/Output Clocking . . . . . . . . . . . C-17

External Clocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-18

External Triggering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-18

Data Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-19

D/A Conversion Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-20

D/A Data Lost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-21

Digital Input and Output Subsystems . . . . . . . . . . . . . . . . . . . C-21

Logical Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-21

Digital Input Initialization. . . . . . . . . . . . . . . . . . . . . . . . . . C-22

Digital Output Initialization . . . . . . . . . . . . . . . . . . . . . . . . C-22

Digital I/O Conversion Delay . . . . . . . . . . . . . . . . . . . . . . . C-22

Digital I/O Data Lost. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-22

Counter/Timer Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-23

Counter/Timer Initialization . . . . . . . . . . . . . . . . . . . . . . . . C-23

Counter/Timer Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . C-23

vi

List of Figures

Figure 2-1. Block Diagram of Basic DAS-1800ST/HR

Series Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Figure 2-2. Block Diagram of DAS-1800ST-DA

Series Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Figure 2-3. Block Diagram of DAS-1802HR-DA Boards . . . . 2-4

Figure 2-4. Timing of Data Conversion Modes

for Channels 4 to 7. . . . . . . . . . . . . . . . . . . . . . . . 2-16

Figure 2-5. Enabling Conversions with a Software Trigger. . 2-19
Figure 2-6. Enabling Conversions with a Hardware Trigger . 2-19

Figure 2-7. Hardware Gate. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Figure 2-8. Timing Relationship between Data

from DO0 to DO3 and Latch Strobe DOSTB . . .2-24

Figure 2-9. Timing for the TGOUT Signal . . . . . . . . . . . . . . 2-25

Figure 2-10. Timing for SSHO Signal When Not Used

for SSH Hardware . . . . . . . . . . . . . . . . . . . . . . . . 2-27

Figure 3-1. Location of Base Address Switch . . . . . . . . . . . . .3-5

Figure 4-1. Connector Layout of an STA-1800U Accessory. .4-2
Figure 4-2. Attaching an STA-1800U Accessory

to a DAS-1800ST/HR Series Board . . . . . . . . . . . 4-2

Figure 4-3. Pin Assignments for the Main I/O Connector

of a DAS-1800ST/HR Series Board . . . . . . . . . . . 4-3

Figure 4-4. Pin Assignments for Connectors J1 and J2

of the STA-1800U . . . . . . . . . . . . . . . . . . . . . . . . .4-4

Figure 4-5. Attaching an STP-50 to a DAS-1800ST/HR

Series Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4-6. Pin Assignments for Screw Terminals

of the STP-50. . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4-7. Attaching an SSH-8 to a DAS-1800ST

Series Board through an STA-1800U . . . . . . . . . .4-6

Figure 4-8. Attaching an MB01 Backplane to a

DAS-1800ST/HR Series Board

through an STA-1800U . . . . . . . . . . . . . . . . . . . . .4-7

Figure 4-9. Attaching MB02 Backplanes to an

STA-1800U Accessory . . . . . . . . . . . . . . . . . . . . .4-8

Figure 4-10. Daisy-Chaining STA-1800U Accessories

with Attached MB02 Backplanes . . . . . . . . . . . . . 4-9

Figure 4-11. Daisy-Chaining EXP-1800 Expansion

Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Figure 4-12. Wiring a Signal Source to a

DAS-1800ST/HR Series Board

Configured for Single-Ended Inputs . . . . . . . . . . 4-13

vii

Figure 4-13. Wiring a Signal Source to

DAS-1800ST/HR Series Board

Configured for Differential Inputs. . . . . . . . . . . .4-14

Figure 4-14. Differential Input Configuration that

Avoids a Ground Loop Problem . . . . . . . . . . . . .4-16

Figure 4-15. Two Connection Schemes for

Synchronizing Multiple Boards. . . . . . . . . . . . . .4-18

Figure 6-1. Potentiometers and Test Points on Basic

DAS-1800ST/HR Series Boards . . . . . . . . . . . . . . 6-2

Figure 6-2. Potentiometers and Test Points on

DAS-1800ST-DA/HR-DA Series Boards . . . . . . .6-3

Figure B-1. Pin Assignments for the Main I/O Connector . . . B-1
Figure B-2. Pin Assignments for Main I/O Connectors

J1 and J2 of the STA-1800U Accessory . . . . . . . B-2

Figure B-3. Pin Assignments for STA-1800U Connector J3 . B-3
Figure B-4. Pin Layouts and Assignments for STA-1800U

Connectors J4 to J7 and Jumper Pads J8 to J11. . B-4

List of Tables

Table 2-1. DAS-1801ST Input Gains and Ranges

for Unipolar and Bipolar Modes . . . . . . . . . . . . . .2-8

Table 2-2. DAS-1802ST/HR Input Gains and Ranges

for Unipolar and Bipolar Modes . . . . . . . . . . . . . .2-9

Table 2-3. Maximum Throughput for DAS-1800ST Series

Boards (Bipolar Mode - Fixed Gain). . . . . . . . . .2-11

Table 2-4. Maximum Throughput for DAS-1800ST Series

Boards (Unipolar Mode - Fixed Gain). . . . . . . . . 2-11

Table 2-5. Maximum Throughput for DAS-1801ST Boards

(Bipolar Mode - Change of Gain) . . . . . . . . . . . . 2-12

Table 2-6. Maximum Throughput for DAS-1801ST Boards

(Unipolar Mode - Change of Gain) . . . . . . . . . . .2-12

Table 2-7. Maximum Throughput for DAS-1802ST Boards

(Bipolar Mode - Change of Gain) . . . . . . . . . . . . 2-13

Table 2-8. Maximum Throughput for DAS-1802ST Boards

(Unipolar Mode - Change of Gain) . . . . . . . . . . .2-13

Table 2-9. Maximum Throughput for DAS-1802HR Boards

(Bipolar Mode - Change of Gain) . . . . . . . . . . . . 2-14

Table 2-10. Maximum Throughput for DAS-1802HR Boards

(Unipolar Mode - Change of Gain) . . . . . . . . . . .2-14

Table 3-1. I/O Address Map (000H to 3FFH). . . . . . . . . . . . . 3-7

Table 4-1. STA-1800U Labels for DAC Outputs . . . . . . . . . . 4-4

Table 4-2. STA-1800U Labels for DAC Outputs . . . . . . . . . 4-16

viii

Table 7-1. Troubleshooting Information. . . . . . . . . . . . . . . . .7-3

Table A-1. Analog Input Specifications for

DAS-1800ST Series. . . . . . . . . . . . . . . . . . . . . . . A-1

Table A-2. Analog Input Specifications for

DAS-1800HR Series . . . . . . . . . . . . . . . . . . . . . . A-3

Table A-3. Analog Output Specifications for

DAS-1800ST-DA Series . . . . . . . . . . . . . . . . . . . A-7

Table A-4. Analog Output Specifications for

DAS-1802HR-DA . . . . . . . . . . . . . . . . . . . . . . . . A-7

Table A-5. Digital I/O Specifications . . . . . . . . . . . . . . . . . . A-8

Table A-6. Power Supply Requirements for the DAS-1801ST,

DAS-1802ST, and DAS-1802HR . . . . . . . . . . . . A-9

Table A-7. Power Supply Requirements for the

DAS-1801ST-DA, DAS-1802ST-DA, and

DAS-1802HR-DA . . . . . . . . . . . . . . . . . . . . . . . . A-9

Table C-1. Modes Supported by DAS-1800 Models. . . . . . . C-6

Table C-2. Allowed Operations and Events for

Supported Subsystem Modes. . . . . . . . . . . . . . . . C-7

Table C-3. Table of Logical Channel Numbers for

Eight External EXP-1800 Multiplexers. . . . . . . C-12

Table C-4. Input Voltage and A/D Binary Value . . . . . . . . C-14

Table C-5. Input Voltage and A/D Binary Value . . . . . . . . C-14

Table C-6. Input Voltage and A/D Binary Value . . . . . . . . C-15

Table C-7. Binary Values and D/A Voltage . . . . . . . . . . . . C-20

Table C-8. Logical Channels and Physical Digital I/O . . . . C-21

ix

Preface

This guide is intended to help you understand the installation, interface
requirements, functions, and operation of the DAS-1801ST,
DAS-1802ST, DAS-1802HR boards and their D/A (digital-to-analog)
versions, the DAS-1801ST-DA, DAS-1802ST-DA, and
DAS-1802HR-DA. Unless this guide refers specifically to one of these
boards, the guide refers to all boards collectively as the DAS-1800ST/HR
Series boards. At the same time, the term
members of the DAS-1800 family of data acquisition boards.

This guide focuses primarily on describing the DAS-1800ST/HR Series
boards and their capabilities, setting up the boards and their associated
software, making typical hookups, and operating the DriverLINX
software. There are also chapters on calibration and troubleshooting. To
follow the information and instructions contained in this manual, you
must be familiar with the operation of an IBM PC or compatible in the
Windows 95/98 or Windows NT environment. You must also be familiar
with data acquisition principles and their applications.

The

DAS-1800ST/HR Series User’s Guide

DAS-1800 Series

refers to all

is organized as follows:

●

Section 1 describes features, accessories, and software options of the
boards.

●

Section 2 describes operating features of the boards 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 the
boards.

●

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

●

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

xi

Section 5 briefly describes the DriverLINX Analog I/O program and

●

Test program.

●

Section 6 describes calibration requirements and gives instructions
for starting the DriverLINX calibration program.

●

Section 7 contains information on isolating and determining the
source of operating problems. This section also contains instructions
for obtaining technical support.

●

Appendix A lists the specifications for DAS-1800ST/HR Series
boards.

Appendix B lists the pin assignments for the main I/O connectors of

●

DAS-1800ST/HR Series boards and for the I/O and accessory
connectors of STA-1800U screw terminal accessories.

Appendix C contains DriverLINX configuration information for the

●

DAS-1800 Series boards.

●

An index completes this manual.

xii

1

Overview

The DAS-1800ST/HR Series of data acquisition boards consists of the
following basic models: DAS-1801ST, DAS-1802ST, and DAS-1802HR.
The basic models all accept analog input signals and perform A/D
(analog-to-digital) conversions. If analog output is also required, these
models are available with a D/A (digital-to-analog) conversion option
under the following designations: DAS-1801ST-DA, DAS-1802ST-DA,
and DAS-1802HR-DA.

The DAS-1800ST/HR Series boards are high-performance data
acquisition boards that operate with DriverLINX software that requires:

●

an IBM PC or compatible AT (386 or Pentium CPU) with minimum
of 2 MB of memory

●

at least one CD ROM drive, one fixed disk drive, and one floppy disk
drive

●

Microsoft Windows 95/98, or Windows NT 4.0 or higher

●

a compiler supporting Microsoft Windows development
a mouse is highly recommended.

●

The DAS-1801ST is a 12-bit, high-gain board, while the DAS-1802ST is
a 12-bit, low-gain board. The DAS-1802HR is a 16-bit, low-gain board.

Major features of these boards are as follows:

●

The boards make 16-bit data transfers on the AT bus.

●

The boards are software-configurable for 16 single-ended or eight
differential onboard analog input channels or up to 256 analog input
channels using expansion accessories.

●

Channels are individually software-configurable for gain.

●

DAS-1800ST Series boards acquire data at up to 333 ksamples/s and
12-bit resolution.

1-1

DAS-1802HR boards acquire data at up to 100 ksamples/s and 16-bit

●

resolution.
DAS-1800ST-DA Series boards contain four 12-bit DACs

●

(digital-to-analog converters) whose channels are updated
simultaneously.

●

DAS-1802HR-DA boards contain two 16-bit DACs that are updated
simultaneously.

●

A 1024-location FIFO (first-in, first-out data buffer) ensures data
integrity at all sampling rates.

●

A 256-location channel-gain queue supports high-speed sampling at
the same or different gains, in sequential or non-sequential channel
order, and at the board’s maximum acquisition rate.

●

Burst-mode data acquisition emulates simultaneous-sample-and-hold
(SSH) capability.

●

The DAS-1800ST Series boards support external SSH hardware;
DAS-1800ST Series boards support EXP-1800 expansion accessories
operated at gains of 1 and 50, while DAS-1802HR boards support
EXP-1800 accessories at a gain of one only.

●

External expansion accessories allow a board to acquire data from up
to 256 channels at the board’s maximum acquisition rate.

●

Dual-channel DMA (Direct Memory Access) operation allows the
acquisition of more than 64 ksamples.

●

Pulsed interrupts allow multiple boards to share interrupt levels.
Hardware trigger and gate for A/D conversions have

●

software-selectable polarity.
Triggering capabilities support pre-, post-, and about-trigger

●

acquisitions.

●

The boards have four digital inputs.

●

The boards have four digital outputs with a latch strobe.
All user connections are made through the 50-pin main I/O connector

●

at the rear panel of the computer.
All features are software-programmable except for a board’s base

●

address switch.
The boards provide ±15V and +5V power for external circuitry.

●

For more information on these features, refer to the Functional
Description in Section 2.

1-2 Overview

Supporting Software

The following software for DAS-1800ST/HR Series boards supports all
currently available DAS-1800 Series boards:

●

DAS-1800ST/HR Series standard software package

with DAS-1800ST/HR Series boards. Includes DriverLINX for
Microsoft Windows 95/98 or Windows NT and function libraries for
writing application programs under Windows in a high-level language
such as Microsoft Visual C++, Microsoft Visual Basic, Borland
Delphi support files, LabVIEW, utility programs, and
language-specific example programs.

— Shipped

DriverLINX —

●

the high-performance real-time data-acquisition

device drivers for Windows application development includes:

DriverLINX API DLLs

–

and drivers supporting the

DAS-1800ST/HR Series hardware.

Analog I/O Panel —

–

A DriverLINX program that verifies the
installation and configuration of DriverLINX to your
DAS-1800ST/HR Series board and demonstrates several virtual
bench-top instruments.

–

Learn DriverLINX —

an interactive learning and demonstration
program for DriverLINX that includes a Digital Storage
Oscilloscope.

–

Source Code —
DriverLINX Application Programming Interface files —

–

for the sample programs.

application programming interface files for the DAS-1800ST/HR
Series.

LabVIEW support for DriverLINX —

–

application programming

interface files for the DAS-1800ST/HR Series.

DriverLINX On-line Help System —

–

provides immediate help as

you operate DriverLINX.

Supplemental Documentation —

–

on DriverLINX installation and
configuration, analog and digital I/O programming, counter/timer
programming; technical reference, and information specific to the
DAS-1800ST/HR Series hardware.

Supporting Software 1-3

DAS-1800ST/HR Series utilities —

●

The following utilities are
provided as part of the DAS-1800ST/HR Series standard software
package:

–

Analog I/O Utility —

DriverLINX utility used for data acquisition

and testing board operation.

Accessories

Test Utility —

–

DriverLINX utility used for testing board

operation.

Calibration Utility —

–

DriverLINX utility used for calibration.

The following accessories are available for DAS-1800ST/HR Series
boards.

●

STA-1800U — Screw terminal accessory. This accessory connects to

the main I/O connector of DAS-1800ST/HR Series boards through a
CDAS-2000 cable to make all I/O signals accessible through labeled
screw terminals.

●

STP-50 —

Screw terminal panel. This accessory provides
general-purpose screw-terminal connections in a compact form
factor.

●

RMT-02 — Rack mount enclosure for the STA-1800U accessory.
SSH-8 — An 8-channel, 12-bit, simultaneous sample-and-hold

●

accessory for DAS-1800ST Series boards. Refer to the

Guide

for more information.

SSH-8 User’s

MB Series modules and MB01/02 backplanes —

●

signal-conditioning modules and backplanes. Refer to the

User’s Guide

EXP-1800 —

●

for more information.

A 16-channel expansion accessory that connects

directly to DAS-1800ST/HR Series boards. Refer to the

User’s Guide

PG-408A —

●

for more information.

DC/DC converter. This accessory must be installed on

Plug-in, isolated,

MB Series

EXP-1800

EXP-1800 accessories that use external power.

●

C16-MB1 — A cable with a 37-pin, female, D-type connector and a

26-pin, female header connector for connecting an STA-1800U to an
MB01 backplane.

1-4 Overview

C-2600 — A 24-inch cable for connecting an STA-1800U to an

●

MB02 signal-conditioning backplane.

●

CDAS-2000 Series — The CDAS-2000 is a 24-inch ribbon cable for

connecting a DAS-1800ST/HR Series board to an STA-1800U, an
STP-50, or an EXP-1800. The CDAS-2000/S is a 24-inch shielded
version of the CDAS-2000; this cable is recommended for use with a
DAS-1800HR Series board.

●

CAB-50 Series —

The cable you use to form a daisy chain of
EXP-1800s; this cable is available in two lengths, as follows: the
CAB-50 is 4 inches long, and the CAB-50/1 is 18 inches long.

●

CACC-2000 —

A 24-inch ribbon cable for daisy chaining additional
STA-1800U accessories to the first STA-1800U or additional
EXP-1800 accessories to the first EXP-1800.

●

C-1800 —

An 18-inch ribbon cable with two 37-pin, female, D-type

connectors for connecting an STA-1800U to an SSH-8.

Accessories 1-5

2

Functional Description

This section describes the features of the analog input, analog output
(when applicable) and digital I/O sections of the DAS-1800ST/HR Series
boards. The intent of these descriptions is to familiarize you with the
operating options and to enable you to make the best use of your board.
The block diagram in Figure 2-1 represents the basic DAS-1800ST/HR
Series boards. Figure 2-2 is a block diagram of the DAS-1800ST-DA
Series boards, and Figure 2-3 is a block diagram of the DAS-1802HR-DA
board.

2-1

Chan. 0/0

Inputs

Analog

or

8 Diff.

16 S.E.

Chan. 7/15

GEXT

MUX [7:4]

Inst.

Amp.

Select

Unipolar/Bipolar

ADC

Sampling

8 or 16

Channel

Input MUX

Gain

Select

Trigger/Gate and

Burst Mode Control

QRAM

FIFO

1K x 16

Select

Diff./S.E.

256 x 11

Control

Address

Local Control Bus

Control and

QRAM

Chan.-Gain

Status

Registers

+15V

DC/DC

-15V

Interrupt and

DMA Control

+5V

Converter

ISA AT Bus (16-bit)

Address

Decode &

Prescaler

boards and 16-bit for DAS-1802HR boards.

Note: The sampling ADC is 12-bit for DAS-1800ST Series

TGOUT

SSHO

XPCLK

TGIN

16-Bit

Counter 0

16-Bit

Counter 1

16-Bit

Counter 2

82C54

Timer/Counter

Buffer

Xtal Osc.

DI [3:0]

Latch

DOSTB

DO [3:0]

Figure 2-1. Block Diagram of Basic DAS-1800ST/HR Series Boards

2-2 Functional Description

-15V

TGOUT

SSHO

XPCLK

TGIN

16-Bit

Counter 0

16-Bit

Counter 1

16-Bit

Counter 2

82C54

Timer/Counter

DI [3:0]

Buffer

Xtal Osc.

DO [3:0]

DOSTB

Latch

DC/DC

Converter

+15V

12-Bit

Sampling ADC

Select

Inst.

Unipolar/Bipolar

Amp.

+5V

Trigger/Gate and

Burst Mode Control

Gain

Select

FIFO

1K x 16

QRAM

256 x 11

Control

Address

QRAM

Chan.-Gain

Status

Registers

Control and

Prescaler

Local Control Bus

Interrupt and

Address

Decode &

DMA Control

Select

ISA AT Bus (16-bit)

Figure 2-2. Block Diagram of DAS-1800ST-DA Series Boards

Chan. 0/0

8 or 16

Channel

Inputs

Analog

Input MUX

or

8 Diff.

16 S.E.

Chan. 7/15

Diff./S.E.

Select

GEXT

MUX [7:4]

DAC 0 - 12 Bits

DAC 1 - 12 Bits

ODAC 0

ODAC 1

DAC 2 - 12 Bits

DAC 3 - 12 Bits

ODAC 2

ODAC 3

2-3

Chan. 0/0

Inputs

Analog

or

8 Diff.

16 S.E.

Chan. 7/15

GEXT

MUX [7:4]

ODAC 0

ODAC 1

8 or 16

Channel

Inst.

Amp.

Select

Unipolar/Bipolar

16-Bit

Sampling ADC

+15V

DC/DC

Converter

-15V

Input MUX

+5V

Select

Diff./S.E.

Gain

Select

Trigger/Gate and

Burst Mode Control

256 x 11

QRAM

FIFO

1K x 16

QRAM

Chan.-Gain

Control

Address

Local Control Bus

Status

Control and

DAC 0 - 16 Bits

Registers

DAC 1 - 16 Bits

Interrupt and

DMA Control

Prescaler

Select

Address

Decode &

ISA AT Bus (16-bit)

Figure 2-3. Block Diagram of DAS-1802HR-DA Boards

16-Bit

Counter 2

82C54

Timer/Counter

Buffer

Xtal Osc.

DI [3:0]

Latch

DOSTB

DO [3:0]

SSHO

TGOUT

TGIN

XPCLK

16-Bit

Counter 0

16-Bit

Counter 1

2-4 Functional Description

Analog Input Features

The analog input section of DAS-1800ST/HR Series boards multiplexes
all the active input channels (up to 16 single-ended or eight differential)
down to a single, sampling ADC (analog-to-digital converter). Sampling
resolution of the ADC is 12 bits (one part in 4096) for DAS-1800ST
Series boards and 16 bits (one part in 65,536) for DAS-1802HR boards.
Other features of the analog input section include software-configurable
inputs, a channel-gain queue, data conversion modes, data transfer modes,
trigger and gate control, and clock sources. These features are described
in the following sections.

Differential/Single-Ended Selection

Using DriverLINX software, you can set DAS-1800ST/HR Series boards
to operate at either differential or single-ended inputs (see “DriverLINX
Configuration Notes” on page C-1). Differential inputs measure the
difference between two signals. Single-ended inputs are referred to a
common ground, also called

When you connect single-ended inputs to an STA-1800U accessory, you
can use the accessory’s LL GND or U_CM MD screw terminals for your
common-mode ground reference. You specify your choice using
DriverLINX software (see “DriverLINX Configuration Notes” on page
C-1).

common-mode ground reference.

Generally, you want to use differential inputs for low-level signals whose
noise component is a significant part of the signal or if the signal has a
non-ground common mode. You want to use single-ended inputs for
high-level signals whose noise component is not significant.

The specific level at which one of these input configurations becomes
more effective than the other depends on the application. However, you
should use differential inputs for voltage ranges of 100mV and below.

Analog Input Features 2-5

Low-Side Reference Selection for Single-Ended Inputs

When you use single-ended inputs, you have two ways of connecting the
low side of the amplifier: the analog ground (default) and a user-defined
common mode. The two schemes differ in how the low side of the
instrumentation amplifier is connected. In the default mode, the low side
of the amplifier is connected to analog ground (LL GND). In the
user-defined common mode, the low side of the amplifier is connected to
a pin on the connector for user-defined common mode (U_CM MD).

The user-defined common mode provides a means for eliminating ground
loops in the system by connecting the reference ground for inputs to the
U_CM MD input pin. Since the U_CM MD connection connects to the
high input impedance of the instrumentation amplifier, the signal contains
no power-supply return current.

The user-defined common mode also provides a means for making
single-ended measurements of signals referred to a voltage that is not
ground or whose output range does not include ground. For example, a
common way to perform 4 to 20mA current monitoring is to connect a
loop with a 250
this current range. This method works but uses only 80% of the input
range when connected to a 0 to 5V range. A better way is to use a 312.5Ω
resistor and refer all measurements to 1.25V. The actual output voltage
then ranges from 1.25V to 6.25V; however, since the amplifier low side is
connected to 1.25V, the measurement range is now a span of 5V, making
the entire input range available and increasing resolution of the
measurements by 20%.

Ω

resistor to ground; the resistor yields a 1 to 5V output in

If you use single-ended input configurations, the user-defined common
mode is the recommended alternative. Use the default mode only if you
want the convenience of not having to connect a separate wire for low
input.

Unipolar/Bipolar Selection

Using DriverLINX, you can set the DAS-1800ST/HR Series boards to
operate in either unipolar or bipolar input mode (see “DriverLINX
Configuration Notes” on page C-1). A unipolar signal is always positive
(0 to 5V, for example), while a bipolar signal can swing up and down
between positive and negative peak values (±5V, for example).

2-6 Functional Description

DAS-1800ST/HR Series boards use positive magnitude to represent
unipolar input signals and 2’s complement for bipolar input signals. In a
given input range with the same peak voltage capacity for both modes, the
unipolar mode doubles the converter’s resolution.

Channel-Gain Selection

DAS-1800ST/HR Series boards offer up to 16 single-ended or eight
differential onboard analog input channels. Using expansion accessories,
you can increase the number of available channels to 256. To
accommodate channel and gain settings for up to 256 channels,
DAS-1800ST/HR Series boards contain a RAM storage circuit (QRAM)
for a 256-position channel-gain queue. Each of the 256 queue positions
holds your choice of a channel number and a corresponding gain. You can
enter multiple channels sequentially or non-sequentially and with the
same or different gain codes. Channel expansion, channel sequencing
control, and available gains and input ranges for DAS-1800ST/HR Series
boards are discussed in the following sections.

Channel Expansion

If you require additional analog input channels, you can configure your
DAS-1800ST/HR Series boards for single-ended inputs and attach up to
16 EXP-1800 expansion accessories or up to 16 MB02 backplanes. Either
option can increase your input capacity to 256 channels.

You can daisy-chain EXP-1800 expansion accessories to a
DAS-1800ST/HR Series board using CDAS-2000 or CDAS-2000/S
cables (see Section 4). Since a DAS-1800ST/HR Series board cannot
power a full complement of EXP-1800 expansion accessories, each
EXP-1800 contains screw terminals for attaching external power, a
receptacle for a DC/DC converter, and a switch for changing between
internal and external power.

If you use MB02 backplanes, use one STA-1800U for every four
backplanes. Connect each group of four backplanes to an STA-1800U as
shown in Section 4, and daisy chain any additional STA-1800U
accessories to the first STA-1800U.

Analog Input Features 2-7

Sampling sequences and gain settings for all expansion channels are
communicated through the control lines described in the following two
sections.

Multiplexer Control Lines MUX 4 to MUX 7

Multiplexer lines MUX 4 to MUX 7 control the channel sequencing of
EXP-1800 expansion accessories and MB02 backplanes. These lines
carry the channel-sequencing information from the channel-gain QRAM
through the main I/O connector of DAS-1800ST/HR Series boards.

External Gain Control Line GEXT

External gain line GEXT sets channel gains on EXP-1800 accessories to
1 or 50 (you should not use a gain of 50 with a DAS-1802HR board, as
you may get less than satisfactory resolution). This line carries the
channel gain settings from the channel-gain QRAM through the main I/O
connector of DAS-1800ST/HR Series boards.

Gains and Ranges

The available input gains and their corresponding ranges are listed in
Table 2-1 for the DAS-1801ST boards and in Table 2-2 for the
DAS-1802ST/HR boards.

Table 2-1. DAS-1801ST Input Gains and Ranges

for Unipolar and Bipolar Modes

Gain Unipolar Range Bipolar Range

1 0 to 5V

5 0 to 1V

50 0 to 100mV

250 0 to 20mV

2-8 Functional Description

−

5.0 to +5.0V

−

1.0 to +1.0V

−

100 to +100mV

−

20 to +20mV

Table 2-2. DAS-1802ST/HR Input Gains and Ranges

for Unipolar and Bipolar Modes

Gain Unipolar Range Bipolar Range

1 0.0 to +10.0V

2 0.0 to +5.0V

4 0 to 2.5V

8 0 to 1.25V

Maximum Achievable Throughput Rates

Because you can change input ranges on a per-channel basis, throughput
is likely to drop if you group channels with varying gains in sequence.
The drop occurs because the channels with low-level inputs (magnitude
of 100mV or less) are slower than those with high-level inputs and
because the channels with low-level inputs must drive out the residual
signals left by the high-level inputs. The best way to maximize
throughput is to use a combination of sensible channel grouping and
external signal conditioning. When using the channel-gain queue,
consider the following suggestions.

●

Keep all channels configured for a particular range together, even if
you have to arrange the channels out of sequence.

●

If your application requires high-speed scanning of low-level signals,
use external signal conditioning to amplify the signal to ±5V or 0 to
5V. This method offers the advantages of increasing total system
throughput and reducing noise.

−

10 to +10V

−

5.0 to +5.0V

−

2.5 to + 2.5V

−

1.25 to +1.25V

●

If you are not using all the channels, you can make a particular
channel-gain entry twice to allow for settling time. Consequently, you
will ignore the results of the first entry.

●

If you are measuring steady-state signals, do not use the channel-gain
queue. Instead, use software to step through the channels and perform
single-channel acquisitions. For example, using software-controlled
single-channel acquisitions to acquire 1000 samples on channel 0 at a
gain of 1 and then 2000 samples on channel 1 at a gain of 250
virtually eliminates interference. This method is best for measuring
steady-state signals even if all the channels are at the same gain.

Analog Input Features 2-9