Tektronix DAS-1800HC Series Users Guide

DAS-1800HC 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-1800HC Series

User’s Guide

Revision F - August 2000

Part Number: 77150

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, 1995, 1994, 1993.

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 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.

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

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 con-

nections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation re-

quires 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

Overview

1

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

Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Functional Description

2

Analog Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

Differential/Single-Ended Selection . . . . . . . . . . . . . . . . . . . .2-3

Unipolar/Bipolar Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Channel-Gain Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

Gains and Ranges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Maximum Achievable Throughput Rates. . . . . . . . . . . . . . 2-5

Data Conversion Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

Clock Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Pacer Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

Burst Mode Conversion Clock. . . . . . . . . . . . . . . . . . . . .2-12

Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Pre-Trigger Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . .2-14

About-Trigger Acquisition . . . . . . . . . . . . . . . . . . . . . . . . 2-14

Post-Trigger Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Data Transfer Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

Analog Output Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

Digital I/O Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18

Using Digital Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . 2-18

Using Digital Control Signal DOSTB . . . . . . . . . . . . . . . . . 2-18

Using Digital Control Signal TGOUT . . . . . . . . . . . . . . . . . 2-19

Using Digital Control Signal SSHO . . . . . . . . . . . . . . . . . . .2-20

Assigning an Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-22

iii

3

Setup and Installation

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

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

Installing the DAS-1800HC 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-1800HC Board with DriverLINX. . . . . . .3-6

4

Cabling and Wiring

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

Attaching the CJC Circuit of an STA-1800HC . . . . . . . . . . . . . . 4-5

Attaching a CONN-1800HC . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6

Attaching an SSH-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7

Attaching MB01 Backplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Attaching an STP-100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-9

Connecting Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10

Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10

Precautions for Using DAS-1801HC Boards

at High Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

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

Connecting a Signal to a Single-Ended Analog Input. . . . . .4-12

Connecting a Signal to a Differential Analog Input . . . . . . .4-12

Common Connection Schemes for Differential Inputs . .4-12

Avoiding Ground Loops with Differential Inputs . . . . . .4-14

Connecting Analog Output Signals. . . . . . . . . . . . . . . . . . . .4-15

Connecting Digital I/O Signals. . . . . . . . . . . . . . . . . . . . . . .4-15

Connecting Digital Control Signals . . . . . . . . . . . . . . . . . . . 4-15

Connecting and Synchronizing Multiple Boards . . . . . . . . .4-16

5

Testing the Board

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

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

Calibration

6

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

Potentiometers and Test Points . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

DriverLINX Calibration Utility. . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

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 . . . . . . . . . . . . . .7-3

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

I/O Connector Pin Assignments. . . . . . . . . . . . . . . . . . . . . . . . . B-1

STA-1800HC and CONN-1800HC 37-Pin D Connectors. . . . . B-4

C

DriverLINX Configuration Notes

Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

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

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-10

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

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

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

v

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-15

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-23

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

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

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

Index

List of Figures

Figure 2-1. Block Diagram of DAS-1800HC Series Board. . .2-2
Figure 2-2. Timing of Conversion Modes

for a Queue of Channels 4 to 7 . . . . . . . . . . . . . . 2-10

Figure 2-3. Enabling Conversions with Software

Triggering/Gating and With Internal

and External Clock Sources. . . . . . . . . . . . . . . . .2-13

Figure 2-4. Enabling Conversions with a Hardware Trigger .2-14

Figure 2-5. Hardware Gate. . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

Figure 2-6. Timing Relationship between Data

from DO0 to DO7 and Latch Strobe DOSTB . . . 2-19

Figure 2-7. Timing for the Generation of TGOUT . . . . . . . .2-20

Figure 2-8. Timing for SSHO Generation

When Not Used for SSH Hardware. . . . . . . . . . .2-21

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

vi

Figure 4-1. Pin Assignments for the Main I/O Connector

of the DAS-1800HC Series Boards. . . . . . . . . . . . 4-2

Figure 4-2. Pin Assignments for the Main I/O Connector

of the STA-1800HC. . . . . . . . . . . . . . . . . . . . . . . . 4-3

Figure 4-3. Cabling and Connections for Attaching an

STA-1800HC. . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4

Figure 4-4. CJC Circuit Schematic. . . . . . . . . . . . . . . . . . . . . . 4-5

Figure 4-5. Location of CJC Circuit Screw

Terminals (TB11) . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4-6. Cabling and Connections for Attaching a

CONN-1800HC to a DAS-1800HC

Series Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6

Figure 4-7. Cabling and Connections for Attaching SSH-8

Accessories to a DAS-1800HC Series Board . . . .4-7

Figure 4-8. Cabling and Connections for Attaching MB01

Backplanes to an STA-1800HC or a

CONN-1800HC. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Figure 4-9. Attaching an STP-100 . . . . . . . . . . . . . . . . . . . . . .4-9

Figure 4-10. Connections for Wiring a Signal Source to a

DAS-1800HC Series Board Configured for

Single-Ended Inputs. . . . . . . . . . . . . . . . . . . . . . .4-12

Figure 4-11. Three Types of Connections for Wiring a Signal

Source to a DAS-1800HC Series Board

Configured for Differential Inputs. . . . . . . . . . . .4-13

Figure 4-12. A Differential Input Configuration that Avoids

a Ground Loop. . . . . . . . . . . . . . . . . . . . . . . . . . .4-14

Figure 4-13. Differential Input Configuration with a

Ground Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Figure 4-14. Two Connection Schemes for

Synchronizing Multiple Boards. . . . . . . . . . . . . .4-16

Figure 6-1. Potentiometers and Test Points on the

DAS-1800HC Series Boards . . . . . . . . . . . . . . . . .6-2

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

of DAS-1800HC Series Boards. . . . . . . . . . . . . . B-2

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

of the STA-1800HC, STP-100, and

CONN-1800HC. . . . . . . . . . . . . . . . . . . . . . . . . . B-3

Figure B-3. Connector J1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Figure B-4. Connector J2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Figure B-5. Connector J3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-5

Figure B-6. Accessory Connector J4 . . . . . . . . . . . . . . . . . . . B-5

vii

List of Tables

Table 2-1. DAS-1801HC Gains and Ranges for

Unipolar and Bipolar Modes . . . . . . . . . . . . . . . . . 2-4

Table 2-2. DAS-1802HC Gains and Ranges for

Unipolar and Bipolar Modes . . . . . . . . . . . . . . . . . 2-4

Table 2-3. Throughput for Channel-to-Channel

Sampling in Bipolar Mode with Fixed Gain . . . . .2-6

Table 2-4. Throughput for Channel-to-Channel

Sampling in Unipolar Mode with Fixed Gain . . . .2-7

Table 2-5. Maximum Throughput for DAS-1801HC

in Bipolar Mode. . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

Table 2-6. Maximum Throughput for DAS-1801HC

in Unipolar Mode. . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Table 2-7. Maximum Throughput for DAS-1802HC

in Bipolar Mode. . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

Table 2-8. Maximum Throughput for DAS-1802HC

in Unipolar Mode. . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

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

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

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

Table A-2. Analog Output Specifications . . . . . . . . . . . . . . . A-4

Table A-3. Digital I/O Specifications . . . . . . . . . . . . . . . . . . A-4

Table A-4. Power Supply Specifications. . . . . . . . . . . . . . . . A-5

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

viii

Preface

This guide is for persons needing to understand the installation, interface
requirements, functions and operation of the DAS-1801HC and
DAS-1802HC boards. The two models differ only in gain. Unless this
manual refers specifically to the DAS-1801HC board or the
DAS-1802HC board, it refers to the two models collectively as the
DAS-1800HC Series boards.

This guide focuses primarily on describing the DAS-1800HC Series
boards and their capabilities, setting up the boards and their associated
software, making typical hookups, and operating the DriverLINX
software. There are also sections 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-1800HC Series User’s Guide

●

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

is organized as follows:

●

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.

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

●

Test program.

ix

●

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-1800HC Series boards.

●

Appendix B lists the pin assignments for the main I/O connectors of
DAS-1800HC Series boards and for the four 37-pin accessory
connectors of the STA-1800HC and CONN-1800HC accessories.

●

Appendix C contains DriverLINX configuration information for the
DAS-1800 Series boards.

●

An index completes this manual.

x

1

Overview

The DAS-1800HC 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 a 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-1801HC is a high-gain board, while the DAS-1802HC is a
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 64 single-ended or 32
differential analog input channels.

Channels are individually software-configurable for gain.

●

●

The boards measure inputs at up to 333 ksamples/s with 12-bit
resolution.

●

A 1024-location FIFO (First In First Out) data buffer ensures data
integrity at all sampling rates.

●

A 64-location channel/gain queue supports high-speed sampling at
the same or different gains and in sequential or non-sequential
channel order.

●

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

●

The boards support external SSH hardware.

1-1

Single- or dual-DMA (Direct Memory Access) operation is

●

software-configurable.

●

Interrupt levels are software-configurable.

●

Pulsed interrupts allow multiple DAS-1800 Series boards to share
interrupt levels.

Hardware A/D (analog-to-digital) trigger and gate have

●

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

●

acquisitions.
Dual 12-bit DAC (digital-to-analog converter) outputs have

●

simultaneous updates.
The boards have four digital inputs.

●

The boards have eight digital outputs with latch strobe.

●

●

A 100-pin I/O connector requires only one slot on rear panel of the
PC A T.

For more information on these features, refer to the functional description
in Section 2.

Supporting Software

The following software is available for operating DAS-1800HC Series
boards:

●

DAS-1800HC Series standard software package

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

●

DriverLINX —

the high-performance real-time data-acquisition

device drivers for Windows application development include:
–

DriverLINX API DLLs

and drivers supporting the DAS-1800HC

Series hardware

1-2 Overview

— Shipped with

–

Analog I/O Panel —

A DriverLINX program that verifies the
installation and configuration of DriverLINX to your
DAS-1800HC 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-1800HC
Series

–

LabVIEW support for DriverLINX —

application programming

interface files for the DAS-1800HC 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-1800HC Series hardware.

●

DAS-1800HC Series utilities —

The following utilities are provided

as part of the DAS-1800HC Series standard software package:
–

Analog I/O Utility —

DriverLINX utility used for data acquisition

and testing board operation.

–

Test Utility —

DriverLINX utility used for testing board

operation.

–

Calibration Utility —

DriverLINX utility used for calibration.

Accessories

The following accessories are available for use with the DAS-1800HC
Series boards:

●

STA-1800HC is a screw terminal accessory. This accessory connects

to the DAS-1800HC Series main I/O connector through a CAB-1800
cable to bring all the I/O signals out to labeled screw terminals for
easy access. Refer to Section 4 for connections.

Accessories 1-3

CONN-1800HC

●

is a connector panel. This accessory connects to the
DAS-1800HC Series main I/O connector through a CAB-1800 Series
cable to provide a 4-connector interface for SSH-8s, MB modules, or
custom hookups.

●

STP-100

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

RMT-04

●

●

SSH-8 is an 8-channel simultaneous-sample-and-hold accessory for

is a rack mount enclosure for the STA-1800HC.

the DAS-1800HC Series boards.

●

MB Series modules and MB01 backplanes

are plug-in, isolated,

signal-conditioning modules and the backplanes that hold them.

●

C-16MB1

is a cable for connecting an STA-1800HC to an MB01

signal-conditioning backplane.

●

CAB-1800 Series

are cables for connecting a DAS-1800HC Series
board to an STA-1800HC, STP-100, or CONN-1800HC. This series
consists of the following cable models:

–

●

CAB-1800

–

CAB-1801

–

CAB-1800/S

–

CAB-1801/S

C-1800

is an 18-inch ribbon cable with two 37-pin female type D

is an 18-inch ribbon cable.

is a 36-inch ribbon cable.

is an 18-inch shielded, ribbon cable.
is a 36-inch shielded, ribbon cable.

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

1-4 Overview

2

Functional Description

This section describes features of the following DAS-1800HC Series
board components: the analog input, the analog output, and the digital
I/O. These descriptions are offered 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 both the DAS-1801HC and the
DAS-1802HC.

2-1

Chan. 0/0

Inputs

Analog

or

32 Diff.

64 S.E.

Chan. 31/63

DAC 0 Out

DAC 1 Out

Uni./Bip. Select

Inst.

Amp.

Sampling

12-bit ADC

32 or 64

Channel

Input MUX

Gain

Select

Control

Burst Mode

T rigger/Gate and

64 x 8

QRAM

FIFO

1K x 16

Select

Diff./S.E.

DAC 0 (12 Bits)

QRAM

Gain/Chan.

Control

Address

Local Control Bus

Status

Control and

+15V

-15V

DAC 1 (12 Bits)

Interrupt

Registers

DC/DC

Converter

Control

and DMA

+5V

ISA PC/AT Bus (16-bit)

Select

Address

Decode &

SSHO

TGOUT

TGIN/DI1

XPCLK/DI0

16-Bit

Counter 0

16-Bit

Counter 1

16-Bit

Counter 2

82C54

Timer/Counter

Prescaler

Buffer

Xtall Osc.

DI [3:0]

Latch

DOSTB

DO [7:0]

Figure 2-1. Block Diagram of DAS-1800HC Series Board

2-2 Functional Description

Analog Input Features

The analog input section of a DAS-1800HC Series board multiplexes all
the active input channels (up to 64 single-ended or 32 differential) down
to a single, 12-bit sampling ADC (analog-to-digital converter). Other
features of this section include software-configurable input modes, a
channel-gain queue, data conversion modes, data transfer modes, and
trigger and gate control. These features are described in the following
subsections.

Differential/Single-Ended Selection

Using DriverLINX software, you can set DAS-1800HC 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
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.

common-mode ground reference.

Generally,

There is no specific level at which one of these input configurations
becomes more effective than the other. However, you should generally
use differential inputs for voltage ranges of 100mV and below.

Unipolar/Bipolar Selection

Using DriverLINX, you can set the DAS-1800HC 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).

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

Analog Input Features 2-3

Channel-Gain Selection

The channel-gain queue is a RAM storage circuit for a 64-position queue.
Each of the 64 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. Available
gains and input ranges for both DAS-1800HC Series boards are listed in
the following subsection.

Gains and Ranges

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

Table 2-1. DAS-1801HC Gains and Ranges for Unipolar and

Gain Unipolar Range Bipolar Range

Bipolar Modes

1 0 to 5V
5 0 to 1V

50 0 to 100mV

250 0 to 20mV

−

5.0 to +5.0V

−

1.0 to +1.0V

−

100 to +100mV

−

20 to +20mV

Table 2-2. DAS-1802HC 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

−

10 to +10V

−

5.0 to +5.0V

−

2.5 to + 2.5V

−

1.25 to +1.25V

2-4 Functional Description

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:

Put all channels that use the same range in the same group, even if

●

you have to arrange the channels out of sequence.
If your application requires high-speed scanning of low-lev el signals,

●

use external signal conditioning to amplify the signal to the
maximum input range of the board. This method offers the
advantages of increasing total system throughput and reducing noise.

●

In the common case where the low-level inputs are relatively
slow-speed and the high-level inputs are high-speed, you should
maintain two channel lists: one for low-speed inputs, the other for
high-speed inputs.

If you are not using all the channels, you can make a particular

●

channel-gain entry twice to allow for settling time. In this case, you
want to ignore the results of the first entry.

You must give special consideration to the direct measurement of
low-level signals with the DAS-1801HC. When using the ±20mV, 0 to
20mV, ±100mV, or 0 to 100mV ranges, measurement throughput drops
for two reasons:

●

The amplifier cannot settle quickly enough (particularly the ±20mV
and 0 to 20mV ranges).

●

Noise in the measurements is higher and thus requires
post-acquisition filtering (averaging) to achieve accurate results.

The DAS-1801HC would ha ve better noise performance if presented with
a perfect signal in these ranges, but perfect signals are virtually
non-existent in the real world. Since the DAS-1801HC has very high
bandwidth (bandwidth for low-level signals is about 8 to 10MHz) any

Analog Input Features 2-5

noise is amplified and digitized. As a result, you must carry out the
measurement of low-level signals carefully to minimize noise effects.

Low-lev el transducers are best used with signal conditioning. Always use
the ±20mV, 0 to 20mV, ±100mV, and 0 to 100mV ranges with the
differential input mode.

The tables below show throughput for various configurations. Note that
these throughputs are based on driving the input with an ideal voltage
source. The output impedance and drive of the source is far more critical
when making large gain changes between two channels whose inputs are
at opposite extremes of their input ranges, as when a signal near −20mV
is measured after a signal at near +5V. You will get better performance
driving adjacent channels at the same gain. The source needs to be able to
drive both the capacitance of the cable and the RC (resistor-capacitor
product of the multiplexer resistance and the output capacitance) of the
multiplexer and board. The multiplexer is typically about 360Ω (1kΩ
maximum) in series with 90pF output capacitance.

The maximum throughput for sampling one channel at one gain (any
gain) is 333 ksamples/s. The throughput for channel-to-channel sampling
with fixed gain in bipolar mode (0.024% maximum error) is as shown in
Table 2-3.

Table 2-3. Throughput for Channel-to-Channel Sampling in Bipolar Mode with

Fixed Gain

DAS-1801HC Range DAS-1802HC Range Throughput

— ±10.0V 312.5 ksamples/s

±5.00V ±5.00V 312.5 ksamples/s

— ±2.50V 312.5 ksamples/s
— ±1.25V 312.5 ksamples/s

±1.00V — 312.5 ksamples/s

±100mV — 312.5 ksamples/s

±20mV — 75 ksamples/s

2-6 Functional Description

The throughput for channel-to-channel sampling with fixed gain in
unipolar mode (0.024% maximum error) is as shown in Table 2-4.

Table 2-4. Throughput for Channel-to-Channel Sampling in Unipolar Mode with

Fixed Gain

DAS-1801HC Range DAS-1802HC Range Throughput

— 0 to 10.0V 312.5 ksamples/s

0 to 5.00V 0 to 5.00V 312.5 ksamples/s

— 0 to 2.50V 312.5 ksamples/s
— 0 to 1.25V 312.5 ksamples/s

0 to 1.00V — 312.5 ksamples/s

0 to 100mV — 200 ksamples/s

0 to 20mV — 60 ksamples/s

The maximum throughput for a DAS-1801HC, operating in bipolar mode
and having less than 1 LSB of error when driven from an ideal voltage
source, is as shown in Table 2-5.

Table 2-5. Maximum Throughput for DAS-1801HC in Bipolar Mode

Maximum Throughput

Range
From ±5.0V

From ±1.0V
From ±100mV
From ±20mV

Analog Input Features 2-7

To ±5V To ±1.0V To ±100mV To ±20mV

312.5 ksamples/s 250 ksamples/s 200 ksamples/s 70 ksamples/s

250 ksamples/s 312.5 ksamples/s 312.5 ksamples/s 70 ksamples/s

200 ksamples/s 312.5 ksamples/s 312.5 ksamples/s 70 ksamples/s

70 ksamples/s 70 ksamples/s 70 ksamples/s 75 ksamples/s

The maximum throughput for a DAS-1801HC, operating in unipolar
mode and having less than 1 LSB of error when driven from an ideal
voltage source, is as shown in Table 2-6.

Table 2-6. Maximum Throughput for DAS-1801HC in Unipolar Mode

Maximum Throughput

Range
From 0 to 5.0V

From 0 to 1.0V
From 0 to 100mV
From 0 to 20mV

To 0 to 5V To 0 to 1.0V To 0 to 100mV To 0 to 20mV

312.5 ksamples/s 200 ksamples/s 200 ksamples/s 50 ksamples/s

200 ksamples/s 312.5 ksamples/s 250 ksamples/s 60 ksamples/s

200 ksamples/s 250 ksamples/s 250 ksamples/s 60 ksamples/s

50 ksamples/s 60 ksamples/s 60 ksamples/s 60 ksamples/s

The maximum throughput for a DAS-1802HC, operating in bipolar mode
and having less than 1 LSB of error when driven from an ideal voltage
source, is as shown in Table 2-7.

Table 2-7. Maximum Throughput for DAS-1802HC in Bipolar Mode

Maximum Throughput

Range
From ±10.0V

To ±10.0V To ±5.0V To ±2.50V To ±1.25V

312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s

From ±5.0V
From ±2.50V
From ±1.25V

2-8 Functional Description

312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s

312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s

312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s 312.5 ksamples/s

The maximum throughput for a DAS-1802HC, operating in unipolar
mode and having less than 1 LSB of error when driven from an ideal
voltage source, is as shown in Table 2-8.

Table 2-8. Maximum Throughput for DAS-1802HC in Unipolar Mode

Maximum Throughput

Range
From 0 to 10.0V

From 0 to 5.0V
From 0 to 2.5V
From 0 to 1.25V

To 0 to 10.0V To 0 to 5.0V To 0 to 2.5V To 0 to 1.25V

312.5 ksamples/s 312.5 ksamples/s 250 ksamples/s 200 ksamples/s

312.5 ksamples/s 312.5 ksamples/s 250 ksamples/s 200 ksamples/s

250 ksamples/s 250 ksamples/s 312.5 ksamples/s 200 ksamples/s

200 ksamples/s 200 ksamples/s 200 ksamples/s 312.5 ksamples/s

Data Conversion Modes

DAS-1800HC Series boards support two modes of data con v ersion: paced
and burst. The conversion rate for each of these two modes is controlled
by its own clock: the pacer clock for paced mode and the burst mode
conversion clock for burst mode. Other differences between the two data
conversion modes are as follows:

●

Paced mode

is the mode best-suited for continuous scanning of a queue of
channels at a constant rate. In the paced mode, the conversion rate
equals the pacer clock rate. The sample rate, which is the rate at
which a single channel is sampled, is the pacer clock rate divided by
the number of channels in the queue. The internal pacer clock is
programmable from 0.0012Hz to 333kHz.

— Paced mode is the default data conversion mode and

Burst mode

●

— In the burst mode, each pulse from the pacer clock
starts a scan of an entire queue of channels. The conversion rate
during a burst mode scan is equal to the rate of the burst mode
conversion clock. The sample rate, which is the rate at which a single
channel is sampled, is equal to the pacer clock rate.

Analog Input Features 2-9

Pacer Clock

Burst mode can also be used for pseudo-simultaneous
sample-and-hold (SSH) in conjunction with DMA or interrupt
operations.

Figure 2-2 shows the timing relationships of the paced and burst modes
for a queue of channel 4 to channel 7.

Paced Mode Conversions

Burst Mode Conversions

Burst Mode Conversions

(with SSH)

Burst Clock

Figure 2-2. Timing of Conversion Modes for a Queue of Channels 4 to 7

Clock Sources

CH4

CH4

CH5

CH4Hold

CH6

CH5

CH7

CH6

CH5

CH4 CH5

CH4

HoldCH7

CH6

CH5

CH7

CH6

CH7

DAS-1800HC Series boards provide tw o clocks: a pacer clock and a burst
mode conversion clock. In paced mode, the pacer clock works alone to
time interrupt-mode and DMA-mode operations, as shown in Figure 2-2.
In burst mode and burst mode with SSH, the pacer clock and the burst
mode conversion clock work together to time interrupt-mode and
DMA-mode operations, as shown in Figure 2-2. These clock sources are
described in the following subsections.

2-10 Functional Description

Pacer Clock

In paced mode, the pacer clock determines the conversion rate. The
following clock sources are available for paced mode conversions on
DAS-1800HC Series boards:

●

Software

— DAS-1800HC Series boards allo w you to acquire single

samples under program control.

Hardware (internal clock sour ce)

●

— The internal pace clock source
uses the onboard 82C54 counter/timer and a crystal-controlled 5MHz
time base. The internal pacer clock uses two cascaded counters of the
82C54 and is programmable between a maximum allowable rate of
333kHz and a minimum available rate of 0.0012Hz. When not used to
pace the analog input, the internal clock source can serve to pace
other events such as the digital I/O and analog outputs through the use
of interrupts.

Hardware (external clock source)

●

— The external pacer clock
source must be an externally applied TTL-compatible signal attached
to the DI0/XPCLK pin (B39) of the main I/O connector, J1. The
active edge for this clock is programmable.

An external clock source is useful if you want to pace at rates not
available with the 82C54 counter/timer, if you want to pace at uneven
intervals, or if you want to pace on the basis of an external event. An
external clock also allows you to synchronize multiple boards with a
common timing source.

The ADC acquires samples at a maximum of 333 ksamples/s (one

Note:

sample every 3.0µs). If using an external clock, mak e sure that it does not
initiate conversions at a faster rate than the ADC can handle.

If acquiring samples from multiple channels, the maximum sampling rate
for each channel is equal to 333 ksamples/s divided by the number of
channels.

Analog Input Features 2-11