Data Translation DT9837A, DT9837, DT9837B User Manual

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UM-22417-AJ

DT9837 Series User’s Manual

Title Page

Page 2

Copyright Page

Sixteenth Edition August, 2016

Data Translation, Inc. 100 Locke Drive Marlboro, MA 01752-1192 (508) 481-3700 www.datatranslation.com Fax: (508) 481-8620 E-mail: info@datx.com

Information furnished by Data Translation, Inc. is believed to be accurate and reliable; however, no responsibility is assumed by Data Translation, Inc. for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Data Translation, Inc.

Use, duplication, or disclosure by the United States Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer software clause at 48 C.F.R, 252.227-7013, or in subparagraph (c)(2) of the Commercial Computer Software - Registered Rights clause at 48 C.F.R., 52-227-19 as applicable. Data Translation, Inc., 100 Locke Drive, Marlboro, MA 01752.

Data Translation® is a registered trademark of Data Translation, Inc. DT-Open Layers Library

, DataAcq SDKTM, QuickDAQTM, and LV-LinkTM are

, DT-Open Layers for .NET Class

trademarks of Data Translation, Inc.

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

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Radio and Television Interference

This equipment has been tested and found to comply with CISPR EN55022 Class A and EN61000-6-1 requirements and also with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference, in which case the user will be required to correct the interference at his own expense.

Changes or modifications to this equipment not expressly approved by Data Translation could void your authority to operate the equipment under Part 15 of the FCC Rules.

Note: This product was verified to meet FCC requirements under test conditions that included use of shielded cables and connectors between system components. It is important that you use shielded cables and connectors to reduce the possibility of causing interference to radio, television, and other electronic devices.

FCC Page

Canadian Department of Communications Statement

This digital apparatus does not exceed the Class A limits for radio noise emissions from digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communications.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites applicables aux appareils numériques de la class A prescrites dans le Règlement sur le brouillage radioélectrique édicté par le Ministère des Communications du Canada.

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Table of Contents

About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Intended Audience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

How this Manual is Organized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Conventions Used in this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Related Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Where To Get Help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Chapter 1: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Hardware Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Key Features of the DT9837. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Key Features of the DT9837A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Key Features of the DT9837B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Key Features of the DT9837C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Supported Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Supported Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Getting Started Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Part 1: Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Chapter 2: Setting Up and Installing the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Attaching Modules to the Computer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Connecting Directly to the USB Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Connecting to an Expansion Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Configuring the DT9837 Series Device Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Chapter 3: Wiring Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Preparing to Wire Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Wiring Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Wiring Signals to the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Connecting Analog Input Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Connecting an Analog Output Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Connecting a Tachometer Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Connecting a Gate Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

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Contents

Chapter 4: Verifying the Operation of a Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Select the Device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Acquire Data from an Analog Output Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Configure the Analog Output Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Configure the Analog Input Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Configure the Recording Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Configure the Acquisition Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Start the Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Part 2: Using Your Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Chapter 5: Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Analog Input Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Analog Input Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Input Ranges and Gains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

IEPE Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Input Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Input Clock Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Analog Input Conversion Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Single-Value Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Single-Values Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Continuous Scan Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Input Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Start Trigger Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Reference Trigger Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Data Format and Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Analog Output Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Analog Output Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Output Ranges and Gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Output Resolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Output Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Output Conversion Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Single-Value Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Waveform Generation Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Continuous Analog Output Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Reading the Analog Output Value in the Analog Input Data Stream

(DT9837A Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Output Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Data Format and Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

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Tachometer Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Frequency or Period Measurements – Tachometer Counter 0 . . . . . . . . . . . . . . . . . . . . 82

Phase Measurements – Tachometer Counter 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Gate Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Triggering Acquisition on Multiple Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Synchronizing Acquisition on Multiple DT9837A, DT9837B, or DT9837C Modules . . . . 87

Chapter 6: Supported Device Driver Capabilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Data Flow and Operation Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Buffering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Triggered Scan Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Data Encoding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Current and Resistance Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Thermocouple, RTD, and Thermistor Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

IEPE Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Bridge and Strain Gage Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Start Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Reference Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Clocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Counter/Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Contents

Chapter 7: Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

General Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

If Your Module Needs Factory Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Chapter 8: Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Using the Calibration Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Calibrating the Analog Input Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Connecting a Precision Voltage Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Using the Auto-Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Using the Manual Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Calibrating the Analog Output Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Appendix A: Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Analog Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Analog Output Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Tachometer Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

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Contents

Gate Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Trigger Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Master Oscillator Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Power, Physical, and Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Regulatory Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Connector Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Appendix B: Connector Pin Assignments and LED Status Indicators . . . . . . . . . 131

RJ45 (LVDS) Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Gate Input Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

LED Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Appendix C: Register-Level Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

DT9837 Register-Level Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Writing to the General Control Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Writing to EEPROM to Change the Coupling Type and Current Source . . . . . . . . . . 137

Writing to EEPROM to Change the High Power Mode . . . . . . . . . . . . . . . . . . . . . . . . 138

DT9837A, DT9837B, and DT9837C Register-Level Programming . . . . . . . . . . . . . . . . . . . 140

Writing to the General Control Register 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

Writing to EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Page 9

The DT9837 Series includes the DT9837, DT9837A, DT9837B, and DT9837C modules. The first part of this manual describes how to install and set up your DT9837 Series module and device driver, and verify that your module is working properly.

The second part of this manual describes the features of the DT9837 Series modules, the capabilities of the DT9837 Series Device Drivers, and how to program the DT9837 Series modules using the DT-Open Layers for .NET Class Library™ software. Troubleshooting information is also provided.

Note: For more information on the class library, refer to the DT-Open Layers for .NET Class Library User’s Manual. If you are using the DataAcq SDK or a software application to program

your device, refer to the documentation for that software for more information.

Intended Audience

This document is intended for engineers, scientists, technicians, or others responsible for using and/or programming a DT9837 Series module for data acquisition operations in the Microsoft® Windows Vista®, Windows 7, or Windows 8 operating system. It is assumed that you have some familiarity with data acquisition principles and that you understand your application.

About this Manual

How this Manual is Organized

This manual is organized as follows:

• Chapter 1, “Overview,” describes the major features of the DT9837 Series modules, as well as the supported software and accessories for the modules.

• Chapter 2, “Setting Up and Installing the Module,” describes how to install a DT9837 Series module, how to apply power to the module, and how to configure the DT9837 Series Device Drivers.

• Chapter 3, “Wiring Signals,” describes how to wire signals to a DT9837 Series module.

• Chapter 4, “Verifying the Operation of a Module,” describes how to verify the operation of a DT9837 Series module with the Quick DataAcq application.

• Chapter 5, “Principles of Operation,” describes all of the features of the DT9837 Series modules and how to access them in your application.

• Chapter 6, “Supported Device Driver Capabilities,” lists the data acquisition subsystems and the associated features accessible using the DT9837 Series Device Drivers.

• Chapter 7, “Troubleshooting,” provides information that you can use to resolve problems with the DT9837 Series modules and DT9837 Series Device Driver, should they occur.

• Chapter 8, “Calibration,” describes how to calibrate the analog I/O circuitry of the DT9837 Series modules.

Page 10

About this Manual

Conventions Used in this Manual

• Appendix A, “Specifications,” lists the specifications of the DT9837 Series modules.

• Appendix B, “Connector Pin Assignments and LED Status Indicators,” lists the pin assignments of the connectors on the DT9837 Series modules.

• Appendix C, “Register-Level Programming,” describes the registers for the DT9837 Series modules.

• An index completes this manual.

The following conventions are used in this manual:

• Notes provide useful information or information that requires special emphasis, cautions provide information to help you avoid losing data or damaging your equipment, and warnings provide information to help you avoid catastrophic damage to yourself or your equipment.

• Items that you select or type are shown in bold.

Related Information

Refer to the following documents for more information on using the DT9837 Series modules:

• Benefits of the Universal Serial Bus for Data Acquisition. This white paper describes why USB is an attractive alternative for data acquisition. It is available on the Data Translation web site (www.datatranslation.com).

• QuickDAQ User’s Manual (UM-24774). This manual describes how to create a QuickDAQ application to acquire and analyze data from a DT-Open Layers data acquisition module.

• DT-Open Layers for .NET User’s Manual (UM-22161). For programmers who are developing their own application programs using Visual C# or Visual Basic .NET, this manual describes how to use the DT-Open Layers for .NET Class Library to access the capabilities of Data Translation data acquisition devices.

• DataAcq SDK User’s Manual (UM-18326). For programmers who are developing their own application programs using the Microsoft C compiler, this manual describes how to use the DT-Open Layers DataAcq SDK™ to access the capabilities of Data Translation data acquisition devices.

• LV-Link Online Help. This help file describes how to use LV-Link™ with the LabVIEW™ graphical programming language to access the capabilities of Data Translation data acquisition devices.

• Microsoft Windows Vista, Windows 7, or Windows 8 documentation.

• USB web site (http://www.usb.org).

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Where To Get Help

Should you run into problems installing or using a DT9837 Series module, the Data Translation Technical Support Department is available to provide technical assistance. Refer to Chapter 7 for more information. If you are outside the United States or Canada, call your local distributor, whose number is listed on our web site (www.datatranslation.com).

About this Manual

Page 12

About this Manual

Page 13

Overview

Hardware Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Supported Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Supported Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Getting Started Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Page 14

Chapter 1

Hardware Features

The DT9837, DT9837A, DT9837B, and DT9837C are high-performance, multifunction data acquisition modules for the USB (Ver. 2.0 or Ver. 1.1) bus.

Tabl e 1 lists the major differences among the modules.

Table 1: Major Differences Among the DT9837 Series Modules

Feature DT9837 DT9837A DT9837B DT9837C

Connectors BNC BNC BNC BNC (on the DT9837C-BNC) or

Mini XLR (on the DT9837C-XLR)

Maximum A/D Throughput 52.734 kHz 52.734 kHz 105.469 kHz 105.469 kHz

AC Coupling at –3 dB 0.5 Hz 0.1 Hz 0.5 Hz 1 Hz

Current Source 4 mA 4 mA 4 mA 2 mA

A/D Threshold Trigger

Number of Tachometer Counters 1 2 (C/T 0 and 1) 2 (C/T 0 and 1) 0

Fixed Programmable Programmable Programmable

Number of Gate Inputs 0 1b (C/T 2)

Number of Analog Output Channels

Analog Output Readback Capability

Maximum Analog Output Throughput

Analog Output Voltage 10 V @ 1 mA 10 V @ 3 mA – ±3 V @ 2 mA

Analog Output Trigger Types Software trigger

RJ45 Synchronization Connector No Yes Yes Yes

a. For the start trigger on the DT9837, the threshold channel is channel 0 and the threshold level is fixed at 1.0 V.

For the start trigger on the DT9837A and DT9837B, the threshold channel is channel 0 and the analog threshold level is programmable from 0.2 V to

9.8 V with 0.1 V of hysteresis.

For the start trigger on the DT9837C, the threshold channel can be any of the analog input channels and the threshold level is programmable between ±10 V for a gain of 1 and ±1 V for a gain of 10.

For the reference trigger on all modules, the threshold channel can be any of the analog input channels and the threshold level is programmable

between ±10 V for a gain of 1 and ± 1 V for a gain of 10. b. Available on the DT9837A-OEM version. c. Available through a BNC connector on the DT9837B module.

11 0 1

No Yes No No

46.875 kHz (fixed)

only

52.734 kHz – 96 kHz

Software trigger, external digital trigger

1c (C/T 2)

None Software trigger,

external digital trigger

Page 15

Key Features of the DT9837

Figure 1 shows the layout of the DT9837 module.

Overview

Figure 1: DT9837 Module

The key features of the DT9837 module are as follows:

• Simultaneous analog input and waveform analog output operations

• Analog input subsystem:

− Four, simultaneous 24-bit A/D converters

− Throughput rate up to 52.734 kSamples/s for simultaneous, high-resolution

measurements

− Input range of ±10 V with software-selectable gains of 1 and 10 for an effective input range of ±10 V and ±1 V

− Support for IEPE (Integrated Electronic Piezoelectric) inputs, including use of a 4 mA current source and AC or DC coupling

− The ability to return the value of tachometer counter 0 in the analog input data stream, allowing you to measure the period or frequency of the tachometer input signal synchronously with analog input measurements

− Supports a start trigger for acquiring pre-trigger samples and a reference trigger for acquiring post-trigger samples. You can specify the number of post-trigger samples to acquire before stopping the operation.

− For the start trigger, supports a software-programmable trigger source (software, external digital trigger, or a positive-going analog threshold trigger on analog input channel 0). The threshold level is fixed at 1.0 V for the analog threshold trigger.

Page 16

Chapter 1

− For the reference trigger, supports a positive- or negative-going analog threshold trigger on any of the analog input channels. You can program the threshold value from –10 V to +10 V.

• Analog output subsystem:

− One 24-bit D/A converter

− Waveform capability of up to 8,192 sample

− Output rate of 46.875 kSamples/s

− Output range of ±10 V

− A software trigger starts the analog output operation

• Internal clock source (shared between the analog input and analog output subsystems)

Key Features of the DT9837A

Figure 2 shows the layout of the DT9837A module.

Figure 2: DT9837A Module

The key hardware features of the DT9837A module are as follows:

• Simultaneous analog input and analog output operations (continuous or waveform mode)

• Analog input subsystem:

− Four, simultaneous 24-bit A/D converters

− Throughput rate up to 52.734 kSamples/s for simultaneous, high-resolution

measurements

Page 17

− Input range of ±10 V with software-selectable gains of 1 and 10 for an effective input

range of ±10 V and ±1 V

− Support for IEPE (Integrated Electronic Piezoelectric) inputs, including use of a 4 mA

current source with 18 V compliance voltage for AC or DC coupling

− The ability to return the value of tachometer counter 0 in the analog input data stream,

allowing you to measure the period or frequency of the tachometer input signal synchronously with analog input measurements

− The ability to read the value of tachometer counter 1 in the analog input data stream,

allowing you to precisely correlate tachometer measurements with analog input measurements

− Optional OEM version of this module, called the DT9837A-OEM, supports the ability

to read the value of gate counter 2 in the analog input data stream, allowing you to precisely correlate gate input measurements with analog input measurements

− Supports reading analog output values in the analog input data stream, allowing you

to correlate input and output values

− Supports a start trigger for acquiring pre-trigger samples and a reference trigger for

acquiring post-trigger samples. You can specify the number of post-trigger samples to acquire before stopping the operation.

Overview

− For the start trigger, supports a software-programmable trigger source (software,

external digital trigger, or a positive-going analog threshold trigger on analog input channel 0). You can program the analog input threshold value from 0.2 V to 9.8 V with

0.1 V of hysteresis.

− For the reference trigger, supports a positive- or negative-going analog threshold

trigger on any of the analog input channels. You can program the threshold value from –10 V to +10 V.

• Analog output subsystem:

− One 24-bit D/A converter

− Single value, waveform, and continuous streaming output

− Programmable output rate from 10 kSamples/s to 52.734 kSamples/s

− Output range of ±10 V

− Software-programmable trigger source (software trigger, external digital trigger, or

analog threshold trigger) to start the analog output operation.

• Internal clock source (shared between the analog input and analog output subsystems)

• RJ45 synchronization (LVDS) connector for synchronizing acquisition on up to four DT9837A modules

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Chapter 1

Key Features of the DT9837B

Figure 3 shows the layout of the DT9837B module.

Figure 3: DT9837B Module

The key hardware features of the DT9837B module are as follows:

• Four, simultaneous 24-bit A/D converters

• Internal clock source with a throughput rate up to 105.469 kSamples/s for simultaneous, high-resolution analog input measurements

• Input range of ±10 V with software-selectable gains of 1 and 10 for an effective input range of ±10 V and ±1 V

• Support for IEPE (Integrated Electronic Piezoelectric) inputs, including use of a 4 mA current source with 18 V compliance voltage for AC or DC coupling

• The ability to return the value of tachometer counter 0 in the analog input data stream, allowing you to measure the period or frequency of the tachometer input signal synchronously with analog input measurements

• The ability to read the value of tachometer counter 1 in the analog input data stream, allowing you to precisely correlate tachometer measurements with analog input measurements

• The ability to read the value of gate counter 2 in the analog input data stream, allowing you to precisely correlate gate input measurements with analog input measurements

Page 19

• Supports a start trigger for acquiring pre-trigger samples and a reference trigger for acquiring post-trigger samples. You can specify the number of post-trigger samples to acquire before stopping the operation.

• For the start trigger, supports a software-programmable trigger source (software, external digital trigger, or a positive-going analog threshold trigger on analog input channel 0). You can program the analog input threshold value from 0.2 V to 9.8 V with 0.1 V of hysteresis.

• For the reference trigger, supports a positive- or negative-going analog threshold trigger on any of the analog input channels. You can program the threshold value from –10 V to +10 V.

• RJ45 synchronization (LVDS) connector for synchronizing acquisition on up to four DT9837B modules

Key Features of the DT9837C

Figure 4 shows the layout of DT9837C module. The model shown is the board-level, OEM

version with mini-XLR connectors.

Overview

Figure 4: DT9837C Module

Page 20

Chapter 1

The key hardware features of the DT9837C module are as follows:

• Simultaneous analog input and analog output operations (continuous or waveform mode)

• Mini-XLR connectors (on the DT9837C-XLR) or BNC connectors (on the DT9837C-BNC) for connecting audio inputs

• Analog input subsystem:

− Four, simultaneous 24-bit A/D converters

− Throughput rate up to 105.469 kSamples/s for simultaneous, high-resolution

measurements

− Input range of ±10 V with software-selectable gains of 1 and 10 for an effective input

range of ±10 V and ±1 V

− Support for IEPE (Integrated Electronic Piezoelectric) inputs, including use of a 2 mA

current source with 18 V compliance voltage for AC and DC coupling

− 1 Hz high-pass filter

− Supports a start trigger for acquiring pre-trigger samples and a reference trigger for

acquiring post-trigger samples. You can specify the number of post-trigger samples to acquire before stopping the operation.

− For the start trigger, supports a software-programmable trigger source (software,

external digital trigger, or analog threshold trigger). You can program the analog input threshold trigger to come from any analog input channel, to be positive- or negative-going, and to have a threshold value from –10 V to +10 V.

− For the reference trigger, supports a positive- or negative-going analog threshold

trigger on any of the analog input channels. You can program the threshold value from –10 V to +10 V.

• Analog output subsystem:

− One 24-bit D/A converter

− Single value, waveform, and continuous streaming output

− Programmable output rate from 10 kSamples/s to 96 kSamples/s

− Output range of ±3 V

− ±2 mA output current

− Software-programmable trigger type (software trigger, external digital trigger, or

analog threshold trigger) to start the analog output operation.

• Internal clock source (shared between the analog input and analog output subsystems)

• RJ45 synchronization (LVDS) connector for synchronizing acquisition on up to four DT9837C modules

Page 21

Supported Software

The following software is available for use with the DT9837 Series modules and is included on the Data Acquisition OMNI CD:

• DT9837 Series Device Drivers – Two device drivers are provided in the DT9837 Series: one for the DT9837 module and one for the DT9837A, DT9837B, and DT9837C modules. The DT9837 Series Device Drivers allow you to use a DT9837, DT9837A, DT9837B, or DT9837C module with any of the supported software packages or utilities.

• DT9837 Series Calibration Utility – This utility, described in Chapter 8 starting on page

111, allows you to calibrate the analog input and analog output circuitry of a DT9837

Series module.

• QuickDAQ Base Version – The base version of QuickDAQ is free-of-charge and allows you to acquire and analyze data from all Data Translation USB and Ethernet devices, except the DT9841 Series, DT9817, DT9835, and DT9853/54. Using the base version of QuickDAQ, you can perform the following functions:

− Discover and select your devices.

− Configure all input channel settings for the attached sensors.

− Load/save multiple hardware configurations.

Overview

− Generate output stimuli (fixed waveforms, swept sine waves, or noise signals).

− On each supported data acquisition device, acquire data from all channels supported

in the input channel list.

− Choose to acquire data continuously or for a specified duration.

− Choose software or triggered acquisition.

− Log acquired data to disk in an .hpf file.

− Display acquired data during acquisition in either a digital display using the Channel

Display window or as a waveform in the Channel Plot window.

− Choose linear or logarithmic scaling for the horizontal and vertical axes.

− View statistics about the acquired data, including the minimum, maximum, and mean

values and the standard deviation in the Statistics window.

− Export time data to a .csv or .txt file; you can open the recorded data in Microsoft

Excel® for further analysis.

− Read a previously recorded .hpf data file.

− Customize many aspects of the acquisition, display, and recording functions to suit

your needs, including the acquisition duration, sampling frequency, trigger settings, filter type, and temperature units to use.

Page 22

Chapter 1

• QuickDAQ FFT Analysis Option – When enabled with a purchased license key, the QuickDAQ FFT Analysis option includes all the features of the QuickDAQ Base version with the FFT Analysis option plus basic FFT analysis features, including the following:

− The ability to switch between the Data Logger time-based interface and the FFT

Analyzer block/average-based interface.

− Supports software, freerun, or triggered acquisition with accept and reject controls for

impact testing applications.

− Allows you to perform single-channel FFT (Fast Fourier Transform) operations,

including AutoSpectrum, Spectrum, and Power Spectral Density, on the acquired analog input data. You can configure a number of parameters for the FFT, including the FFT size, windowing type, averaging type, integration type, and so on.

− Allows you to display frequency-domain data as amplitude or phase.

− Supports dB or linear scaling with RMS (root mean squared), peak, and peak-to-peak

scaling options

− Supports linear or exponential averaging with RMS, vector, and peak hold averaging

options.

− Supports windowed time channels.

− Supports the following response window types: Hanning, Hamming, Bartlett,

Blackman, Blackman Harris, and Flat top.

− Supports the ability to lock the waveform output to the analysis frame time.

− Allows you to configure and view dynamic performance statistics, including the input

below full-scale (IBF), total harmonic distortion (THD), spurious free dynamic range (SFDR), signal-to-noise and distortion ratio (SINAD), signal-to-noise ratio (SNR), and the effective number of bits (ENOB), for selected time-domain channels in the Statistics window.

− Supports digital IIR (infinite impulse response) filters.

• QuickDAQ Advanced FFT Analysis Option – When enabled with a purchased software license, the QuickDAQ Advanced FFT Analysis option includes all the features of the QuickDAQ Base version with the FFT Analysis option plus advanced FFT analysis features, including the following:

− Allows you to designate a channel as a Reference or Response channel.

− Allows you to perform two-channel FFT analysis functions, including Frequency

Response Functions (Inertance, Mobility, Compliance, Apparent Mass, Impedance, Dynamic Stiffness, or custom FRF) with H1, H2, or H3 estimator types, Cross-Spectrum, Cross Power Spectral Density, Coherence, and Coherent Output Power.

− Supports the Exponential response window type.

− Supports the following reference window types: Hanning, Hamming, Bartlett,

Blackman, Blackman Harris, FlatTop, Exponential, Force, and Cosine Taper windows.

− Supports real, imaginary, and Nyquist display functions.

− Allows you to save data in the .uff file format.

Page 23

• Quick DataAcq application – The Quick DataAcq application provides a quick way to get up and running using a DT9837 Series module. Using this application, you can verify key features of the modules, display data on the screen, and save data to disk. (Note that this application does not support configuring AC/DC coupling or the excitation current source for IEPE inputs.)

• DT-Open Layers for .NET Class Library – Use this class library if you want to use Visual C# or Visual Basic for .NET to develop your own application software for a DT9837 Series module using Visual Studio 2003-2012; the class library complies with the DT-Open Layers standard.

• DataAcq SDK – Use the Data Acq SDK if you want to use Visual Studio 6.0 and Microsoft C or C++ to develop your own application software for a DT9837 Series module using Windows Vista, Windows 7, or Windows 8; the DataAcq SDK complies with the DT-Open Layers standard.

• DAQ Adaptor for MATLAB – Data Translation’s DAQ Adaptor provides an interface between the MATLAB Data Acquisition (DAQ) subsystem from The MathWorks and Data Translation’s DT-Open Layers architecture.

• LV-Link – A link to LV-Link is included on the Data Acquisition OMNI CD. Use LV-Link if you want to use the LabVIEW graphical programming language to access the capabilities of the DT9837 Series module.

Overview

Refer to the Data Translation web site (www.datatranslation.com) for information about selecting the right software package for your needs.

Page 24

Chapter 1

Supported Accessories

The EP386 panel, shown in Figure 5, is available for use with the DT9837A, DT9837B, and DT9837C modules.

Figure 5: EP386 Panel

This RJ45 distribution panel contains four RJ45 connectors that are wired in parallel, making it useful when attaching up to four DT9837A, DT9837B, or DT9837C modules together. Refer to

page 88 for more information on using this panel.

Note: You must have revision H or later of the DT9837A module or revision F or later of the DT9837A-OEM module to be able to attach four modules together. You can identify the revision of your module by looking at the serial number label on your module.

If you have revision G or earlier of the DT9837A or revision E or earlier of the DT9837A-OEM, you can attach a maximum of two modules together.

Page 25

Getting Started Procedure

Set Up and Install the Module

(see Chapter 2 starting on page 29)

Wire Signals

(see Chapter 3 starting on page 39)

Verify the Operation of the Module

(see Chapter 4 starting on page 49)

The flow diagram shown in Figure 6 illustrates the steps needed to get started using a DT9837 Series module. This diagram is repeated in each Getting Started chapter; the shaded area in the diagram shows you where you are in the getting started procedure.

Figure 6: Getting Started Flow Diagram

Overview

Page 26

Chapter 1

Page 27

Part 1: Getting Started

Page 28

Page 29

Setting Up and Installing the Module

Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Attaching Modules to the Computer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Configuring the DT9837 Series Device Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Page 30

Chapter 2

Set Up and Install the Module

(this chapter)

Wire Signals

(see Chapter 3 starting on page 39)

Verify the Operation of the Module

(see Chapter 4 starting on page 49)

Page 31

Unpacking

Open the shipping box and verify that the following items are present:

• DT9837, DT9837A, or DT9837B module

• EP365 USB cable

• Data Acquisition OMNI CD-ROM

If an item is missing or damaged, contact Data Translation. If you are in the United States, call the Customer Service Department at (508) 481-3700, ext. 1323. An application engineer will guide you through the appropriate steps for replacing missing or damaged items. If you are located outside the United States, call your local distributor, listed on Data Translation’s web site (www.datatranslation.com).

Note: The DT9837 Series modules are factory-calibrated. If you decide that you want to recalibrate the analog input or analog output circuitry, refer to the instructions in Chapter 8.

Setting Up and Installing the Module

Page 32

Chapter 2

System Requirements

For reliable operation, ensure that your computer meets the following system requirements:

• Processor: Pentium 4/M or equivalent

•RAM: 1 GB

• Screen Resolution: 1024 x 768 pixels

• Operating System: Windows 8, Windows 7, Windows Vista (32- and 64-bit)

• Disk Space: 4 GB

Page 33

Attaching Modules to the Computer

USB Cable

DT9837 Series Module

Host Computer

USB Ports

This section describes how to attach a DT9837 Series module to the host computer.

Note: Most computers have several USB ports that allow direct connection to USB devices. If your application requires more DT9837 Series modules than you have USB ports for, you can expand the number of USB devices attached to a single USB port by using expansion hubs. For more information, refer to page 34.

You can unplug a module, then plug it in again, if you wish, without causing damage. This process is called hot-swapping. Your application may take a few seconds to recognize a module once it is plugged back in.

The DT9837 Series modules use less than 500 mA; therefore, they do not require an external power supply.

You must install the device driver for your module before connecting the module(s) to the host computer. Run the installation program on your Data Acquisition OMNI CD to install the device driver and other software for the module.

Setting Up and Installing the Module

Connecting Directly to the USB Ports

To connect a DT983 Series module directly to a USB port on your computer, do the following:

1. Attach one end of the USB cable to the USB port on the module.

2. Attach the other end of the USB cable to one of the USB ports on the host computer, as

shown in Figure 7.

The operating system automatically detects the USB module and starts the Found New Hardware wizard.

Figure 7: Attaching the Module to the Host Computer

Page 34

Chapter 2

3. For Windows Vista:

a. Click Locate and install driver software (recommended).

The popup message "Windows needs your permission to continue" appears.

b. Click Continue.

The Windows Security dialog box appears.

c. Click Install this driver software anyway.

Note: Windows 7 and Windows 8 find the device automatically.

4. Repeat these steps to attach another DT9837 Series module to the host computer, if

desired.

Note: Once you have connected your module to the host computer, power is turned on to the module when your application program opens the module. The LED on the module turns green to indicate that power is turned on.

Power is turned off to the module when your application program terminates its connection to the module.

Connecting to an Expansion Hub

Expansion hubs are powered by their own external power supply. The practical number of DT9837 Series modules that you can connect to a single USB port depends on the throughput you want to achieve.

To connect multiple DT9837 Series modules to an expansion hub, do the following:

1. Attach one end of the USB cable to the module and the other end of the USB cable to an

expansion hub.

2. Connect the power supply for the expansion hub to an external power supply.

3. Connect the expansion hub to the USB port on the host computer using another USB

cable.

The operating system automatically detects the USB module and starts the Found New Hardware wizard.

4. For Windows Vista

a. Click Locate and install driver software (recommended).

The popup message "Windows needs your permission to continue" appears.

b. Click Continue.

The Windows Security dialog box appears.

c. Click Install this driver software anyway.

Page 35

Setting Up and Installing the Module

USB Cable

Expansion Hubs

Host Computer

Power Supply

for Hub

USB Cables

USB Cable

Powe r Supp ly

for Hub

DT9837 Series

Module

DT9837 Series

Module

DT9837 Series

Module

DT9837 Series

Module

Note: Windows 7 and Windows 8 find the device automatically.

5. Repeat these steps until you have attached the number of expansion hubs and modules

that you require. Refer to Figure 8.

The operating system automatically detects the USB devices as they are installed.

Note: Once you have connected your module to the host computer, power is turned on to the DT9837 Series module when your application program opens the module. The LED on the module turns green to indicate that power is turned on.

Power is turned off to the module when your application program terminates its connection to the module.

Figure 8: Attaching Multiple Modules Using Expansion Hubs

Page 36

Chapter 2

Configuring the DT9837 Series Device Drivers

Note: In Windows 7, Windows 8, and Vista, you must have administrator privileges to run the Open Layers Control Panel. When you double-click the Open Layers Control Panel icon, you may see the Program Compatibility Assistant. If you do, select Open the control panel using recommended settings. You may also see a Windows message asking you if you want to run the Open Layers Control Panel as a "legacy CPL elevated." If you get this message, click Yes.

If you do not get this message and have trouble making changes in the Open Layers Control Panel, right click the DTOLCPL.CPL file and select Run as administrator. By default, this file is installed in the following location:

Windows 7, Windows 8, and Vista (32-bit) C:\Windows\System32\Dtolcpl.cpl

Windows 7, Windows 8, and Vista (64-bit) C:\Windows\SysWOW64\Dtolcpl.cpl

To configure the device driver for a DT9837 Series module, do the following:

1. If you have not already done so, power up the host computer and all peripherals.

2. From the Windows Start menu, select Settings|Control Panel.

3. From the Control Panel, double-click Open Layers Control Panel.

The Data Acquisition Control Panel dialog box appears.

4. If you want to rename the module, click the name of the module that you want to rename,

click Edit Name, enter a new name for the module, and then click OK. The name is used to identify the module in all subsequent applications.

5. Select the module that you want to configure, and then click Advanced.

The Measurement Options dialog box appears.

6. Check the Power Always On box if you want to enable high power mode or uncheck this

box to disable high power mode (the default). Turning off the high-power circuitry helps to conserve power, which may be useful when the module is used with a laptop. However, to ensure that the module is warmed up and that any settling time errors of the IEPE current source are minimized, it is recommended that you check this option to keep the module’s high-power circuitry always turned on.

Page 37

Setting Up and Installing the Module

7. You can read the number of counts between two consecutive starting edges of the

tachometer input signal by including channel 4 (tachometer counter 0) in the analog input channel list. On the DT9837 module, the starting edge is always rising; on the DT9837A and DT9837B modules, the starting edge is programmable (either rising or falling). See

page 82 for more information.

For the DT9837, skip to step 11. For the DT9837A and DT9837B modules, configure the Tach.CT0 measurement parameters as follows:

a. From the Start Select combo box, select the edge (Rising Edge or Falling Edge) of the

tachometer input signal that you want to use to start the measurement.

b. From the Measure Mode combo box, select Zeros if you want to read a value of 0

between measurements, or select Previous Measurement if you want to read the previous measurement value if the new measurement value is not yet complete.

c. From the Stale Data combo box, select Used if you want to indicate whether or not

the measurement value if new, or select Not Used if you do not want to indicate whether the measurement value is new. If you select Used, the most significant bit (MSB) of the measurement value is set to 0 when the value is new and set to 1 when the measurement is not yet complete. If you select Not Used, the MSB of the measurement value is always 0.

8. On the DT9837A and DT9837B modules, you can measure the time from the stopping

edge of the tachometer input signal to the A/D sample or from the A/D sample to the stopping edge of the tachometer input signal by specifying channel 5 (tachometer counter

1) in the analog input channel list; see page 84 for more information. Configure the Tach.CT1 measurement parameters as follows:

a. From the Start Select combo box, select the signal that you want to use to start the

measurement (A/D Sample, Tach Input Rising Edge, or Tach Input Falling Edge).

b. From the Stop Select combo box, select the signal that you want to use to stop the

measurement (A/D Sample, Tach Input Rising Edge, or Tach Input Falling Edge).

Note that if you choose to start the measurement using the A/D sample, choose a tachometer edge to stop the measurement. Likewise, if you choose to stop the measurement using the A/D sample, choose a tachometer edge to start the measurement.

c. From the Self Clear combo box, select Clear to zero if you want to return a value of 0

between measurements, or select Keep last Value if you want to return the previous measurement value between readings.

Page 38

Chapter 2

9. For the DT9837A-OEM and DT9837B modules, you can also measure the time between

the A/D sample to the specified edge of the gate input signal, the time between two gate input signals, or the time between the specified edge of the gate input signal to the A/D sample by specifying channel 6 (gate counter 2) in the analog input channel list; see page

85 for more information. Configure the Gate.CT2 measurement parameters as follows:

a. From the Start Select combo box, select the signal that you want to use to start the

measurement (A/D Sample, Gate Rising Edge, or Gate Falling Edge).

b. From the Stop Select combo box, select the signal that you want to use to stop the

measurement (A/D Sample, Gate Rising Edge, or Gate Falling Edge).

Note that if you choose to start the measurement using the A/D sample, choose a gate edge to stop the measurement. Likewise, if you choose to stop the measurement using the A/D sample, choose a gate edge to start the measurement.

c. From the Self Clear combo box, select Clear to zero if you want to return a value of 0

between measurements, or select Keep last Value if you want to return the previous measurement value between readings.

10. For the Coupling type, select AC for AC coupling or DC for DC coupling.

11. For the Current Source, select Enabled to enable the internal excitation current source or

Disabled to disable the internal excitation current source.

Note: If you enable the use of the internal excitation current source, it is recommended

that you choose AC coupling. Refer to page 44 for more information on wiring IEPE inputs.

12. When you are finished, click OK to close the Measurement Options dialog box.

13. Repeat steps 4 to 11 for the other modules that you want to configure.

14. When you are finished configuring the modules, click Close to close the Control Panel.

Note: If you need to configure these settings programmatically instead of using the Open

Layers Control Panel, you can write to the registers of the module. Refer to Appendix C starting on page 135 for more information.

Page 39

Wiring Signals

Preparing to Wire Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Connecting Analog Input Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Connecting an Analog Output Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Connecting a Tachometer Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Connecting a Gate Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Page 40

Chapter 3

Set Up and Install the Module

(see Chapter 2 starting on page 29)

Wire Signals

(this chapter)

Verify the Operation of the Module

(see Chapter 4 starting on page 49)

Page 41

Preparing to Wire Signals

USB Port

Analog Output

External Trigg er

Analog Inputs

Tachometer

This section provides recommendations and information about wiring signals to a DT9837 Series module.

Wiring Recommendations

Keep the following recommendations in mind when wiring signals to a DT9837 Series module:

• Follow standard ESD procedures when wiring signals to the module.

• Separate power and signal lines by using physically different wiring paths or conduits.

• To avoid noise, do not locate the module and cabling next to sources that produce high electromagnetic fields, such as large electric motors, power lines, solenoids, and electric arcs, unless the signals are enclosed in a mumetal shield.

• Prevent electrostatic discharge to the I/O while the module is operational.

• Connect all unused analog input channels to analog ground.

Wiring Signals

Wiring Signals to the Module

The DT9837 module contains five BNC connectors on one end of the module, and two BNC connectors and a USB connector on the other end of the module as shown in Figure 9.

Figure 9: Connectors on the DT9837 Module

Page 42

Chapter 3

Analog Inputs

Tachometer

USB Port

Analog Output

External Trigger

RJ45 (LVDS) Port

Tach om et er

Analog Inputs

USB Port

Gate Input

External Trigger

RJ45 (LVDS) Port

The DT9837A module, shown in Figure 10, provides all of these connectors and an additional RJ45 LVDS connector for connecting multiple modules. The OEM version of the DT9837A, shown in Figure 17 on page 47, also provides an additional gate input connector.

Figure 10: Connectors on the DT9837A Module (OEM Version Shown)

Figure 11 shows the connectors on the DT9837B module.

Figure 11: Connectors on the DT9837B Module

Page 43

Wiring Signals

USB Port

Analog Output

External Trigger

RJ45 (LVDS) Port

Analog Inputs

USB Port

Analog Output

External Trigger

Analog Inputs

RJ45 (LVDS) Port

Figure 12 shows the connectors on the DT9837C-BNC module (the board-level, OEM version

of the module is shown).

Figure 12: Connectors on the DT9837C-BNC Module

Figure 13 shows the connectors on the DT9837C-XLR module (the board-level, OEM version

of the module is shown).

Figure 13: Connectors on the DT9837C-XLR Module

The remaining sections of this chapter describe how to attach signals to these connectors.

Page 44

Chapter 3

Signal

Source

Analog In 0

Analog In 1

DT9837 Series Module

Connecting Analog Input Signals

You can connect up to four analog input signals (or IEPE sensors) to the BNC connectors on a DT9837 Series module. Internally, these signals are connected in single-ended mode. The DT9837 Series modules support an input signal range of ±10 V (using a gain of 1) or ±1 V (using a gain of 10).

Note: If you enable the use of the internal excitation current source for IEPE inputs, it is recommended that you choose AC coupling. Refer to page 68 for more information on IEPE inputs.

Figure 14 shows how to connect analog inputs (channels 0 and 1, in this case) to the connectors

on the DT9837 Series modules.

Figure 14: Connecting Analog Inputs to a DT9837 Series Module

Page 45

Connecting an Analog Output Signal

Note that the connector automatically connects the Analog Ground signal appropriately.

Load

Analog Out 0

DT9837, DT9837A, or

DT9837C Module

The DT9837, DT9837A, and DT9837C modules provide one analog output channel with an output range of ±10 V. Figure 15 shows how to connect an analog output signal to the DT9837, DT9837A, or DT9837C module.

Wiring Signals

Figure 15: Connecting an Analog Output Signal to a

DT9837, DT9837A, or DT9837C Module

Page 46

Chapter 3

Signal

Source

Tachometer In 0

DT9837 DT9837A, or

DT9837B Module

Connecting a Tachometer Input Signal

You can connect a ±30 V tachometer input signal to the tachometer input BNC on a DT9837, DT9837A, or DT9837B module, as shown in Figure 16.

Note: In software, you can read tachometer measurements as part of the analog input channel list. Refer to page 82 for more information on tachometer measurements.

Figure 16: Connecting a Tachometer Input Signal to a DT9837, DT9837A, or DT9837B Module

Page 47

Connecting a Gate Input Signal

Gate Input

Digital

Ground

External Source

Gate Input Connector

DT9837A-OEM Module

J12

The DT9837A-OEM module provides a 4-pin Gate Input connector for measuring period, frequency, and pulse width values. The DT9837B provides a BNC connector for attaching a gate input signal. Figure 17 shows how to connect a TTL gate input signal to the DT9837A-OEM module.

Wiring Signals

Figure 17: Connecting a Gate Input Signal to the DT9837A-OEM Module

Page 48

Chapter 3

Note that the BNC automatically connects the Digital Ground signal appropriately.

Signal

Source

Gate Input

DT9837B Module

Figure 18 shows how to attach a TTL gate input signal to a DT9837B module.

Figure 18: Connecting a Gate Input Signal to a DT9837B Module

Note: In software, you can read the gate measurements as part of the analog input channel list. Refer to page 85 for more information on gate input measurements.

Page 49

Verifying the Operation of a Module

Select the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Acquire Data from an Analog Output Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Page 50

Chapter 4

Set Up and Install the Module

(see Chapter 2 starting on page 29)

Wire Signals

(see Chapter 3 starting on page 39)

Verify the Operation of the Module

(this chapter)

You can verify the operation of a DT9837 Series module using the QuickDAQ application.

QuickDAQ allows you to acquire and analyze data from all Data Translation USB and Ethernet devices, except the DT9841 Series, DT9817, DT9835, and DT9853/54. This chapter describes how to verify the operation of a DT9837 Series module using the QuickDAQ base version.

Page 51

Select the Device

To get started with your DT9837 Series module and the QuickDAQ application, follow these steps:

1. Connect the DT9837 Series module to the USB port of your computer, and connect your

sensors to the module.

2. Start the QuickDAQ application.

The Device Selection window appears.

Verifying the Operation of a Module

3. For the Device Family selection, select OpenLayersDevices.

By default, the application "discovers" all devices that are available for the specified device family and displays the module name for the USB devices in the drop-down list. If you want to refresh this list to determine if other devices are available, click Refresh.

4. Select the module name for the DT9837 Series module that you want to use from the list of

Available Devices, and click Add.

Information about the device, including the model number, serial number, firmware version, driver version, and scanning status is displayed.

Page 52

Chapter 4

If you want to rename your device, do the following:

a. Click the Row Selector button for the device.

b. Click the IP address or module name in the Name column to highlight it and enter a

meaningful name to represent each available device.

5. If you are using multiple devices, you must configure one device as the clock and trigger

master, as follows:

a. Click the Row Selector button for the device that you want to be the clock and trigger

master.

b. For the clock and trigger master device, check the box under the Master column.

6. (Optional) If you want to remove a device from list of selected devices, click the Row

Selector button for the device, and then click Remove.

7. Once you have added all the devices that you want to use with the application, click OK.

The latest state is saved and used when the application is next run; the interface of the QuickDAQ application is displayed.

Page 53

Verifying the Operation of a Module

Page 54

Chapter 4

Acquire Data from an Analog Output Channel

The following steps describe how to use the QuickDAQ application to monitor the output of the analog output signal using an analog input channel.

In this example, a 10 V sine wave is output on analog output channel 0 of a DT9837-C module. The analog output channel is connected to analog input channel 0 on the DT9837-C module.

Note: If you are using a DT9837-B module, attach a voltage source of +/–10 V to analog input channel 0, and skip the next section on configuring the analog output settings.

Configure the Analog Output Settings

For this example, configure the analog output channel as follows:

1. Click the Output tab of the Acquisition and Config window.

Page 55

2. Select the Enable checkbox to enable the analog output channel on the module.

3. For the Waveform type, select Fixed.

4. For Peak Voltage, enter 3 to output a ±3 V signal.

5. For Offset, enter 0.

6. For Signal Type, select Sine to output a sine wave.

7. For Output Mode, select Continuous to output a waveform that repeats continuously.

8. For Frequency, select 10 Hz; this is the frequency of the output waveform.

9. For Ramp Up Time, enter 0.

10. For the Start/Stop Method, select With Acquisition.

The analog output operation will start when you start acquisition.

11. If desired, hide the Acquisition Config window by clicking the Auto-Hide pin ( ) in

the top, right corner of the window.

Configure the Analog Input Channel

Configure the analog input channel as follows:

Verifying the Operation of a Module

1. Ensure that the output from analog output channel 0 is connected to the input of analog

input channel 0.

2. Configure the analog input channel by clicking the Input Channel Configuration toolbar

button ( ) or by clicking the Configuration menu and clicking Input Channel

Configuration.

3. Enable analog input channel 0 by clicking the Enable checkbox next to the channel.

4. Under the Channel Name column, leave the default channel name as Ain 0.

5. Under the Range column, select the input range for analog input channel.

In this example, ±10 V is used.

Page 56

Chapter 4

6. Under the Coupling column, select the coupling type (AC or DC) for your sensor.

Since this example is monitoring a voltage input, DC is used.

7. Under the Current Source column, select whether to enable or disable use of the 4 mA

current source on the data acquisition device.

Since this example is monitoring a voltage input, the Current Source checkbox is not checked (disabled) for the analog input channel.

8. Under the Engineering Units column, select the engineering units for the input.

In this example, V is used.

9. Enter the number of mV per engineering unit in the mV/EU field.

In this example, 1000 is used.

10. If an offset is specified for the input, enter the value in the EU Offset field.

In this example, no offset (0) is specified.

11. If desired, enter a test point value for the channel.

In this example, 1 is used.

12. If desired, enter a sensor direction for each channel.

In this example, the default value of X+ is used.

13. Click Close to close the Configure Devices dialog box.

Page 57

Configure the Recording Settings

For this example, configure the recording settings as follows:

1. Click the Recording tab of the Acquisition Config window.

Verifying the Operation of a Module

2. For Filename generation, use the default Filename option.

3. For Filename, use the default name for the data file.

4. Leave the Enable Continuous Acquisition checkbox unchecked.

5. For Acquisition Duration, select 1 second.

The number of seconds for the total run and the amount of available disk space are shown.

6. For X Span Axis, select 1 second.

Page 58

Chapter 4

Configure the Acquisition Settings

For this example, configure the acquisition settings as follows:

1. Click the Acquisition tab of the Acquisition Config window.

2. For the Per Channel Sampling Frequency text box, enter 10000.

The sampling rate, sample interval, and number of scans are displayed.

3. For the Trigger Source check box, select Software to ensure that the measurement starts

as soon as the Record button is clicked.

Page 59

Start the Operation

Once you have configured the channels and the application parameters, click the Record toolbar button ( ) or press the F5 key to start the operation.

Results similar to the following are displayed in the Channel Plot window, showing the output of analog output channel 0 as measured by analog input channel 0.

Verifying the Operation of a Module

Note: Many additional options are provided in QuickDAQ for measuring and analyzing the data. Refer to the QuickDAQ User’s Manual for detailed information.

Page 60

Chapter 4

Page 61

Part 2: Using Your Module

Page 62

Page 63

Principles of Operation

Analog Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Analog Output Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Tachometer Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Gate Input Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Triggering Acquisition on Multiple Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Synchronizing Acquisition on Multiple DT9837A, DT9837B, or DT9837C Modules . . . . 87

Page 64

Chapter 5

4 mA Current

Source

+18 V Compliance Voltage

1 M

x1, 10

24-Bit

A/D

Control

Logic

4 mA

1 M

x1, 10

24-Bit

A/D

Tac homete r

Input

4 mA

1 M

x1, 10

24-Bit

A/D

4 mA

1 M

x1, 10

24-Bit

A/D

Analog Input 0

Analog Input 1

Analog Input 2

Analog Input 3

24-Bit

D/A

10 kHz

Filter

FIFO

High-

Speed

USB 2.0

Interface

Clock

USB

2.0

Ext Trigger

D/A

Output 0

Sigma-Deltas

0.5 Hz

Figure 19 shows a block diagram of the DT9837 module.

Figure 19: Block Diagram of the DT9837 Module

Page 65

Figure 20 shows a block diagram of the DT9837A module.

4 mA Current

Source

+18 V Compliance Voltage

1 M

x1,

24-Bit

A/D

Control

Logic

4 mA

1 M

x1,

24-Bit

A/D

Tachometer

Input

4 mA

1 M

x1,

24-Bit

A/D

4 mA

1 M

x1,

24-Bit

A/D

Analog Input 0

Analog Input 1

Analog Input 2

Analog Input 3

24-Bit D/A

Sigma-

Delta

10 kHz

Filter

D/A

Clock

High-

Speed

USB 2.0

Interface

D/A

FIFO

USB

2.0

Ext Trigger

D/A

Output 0

Tri gger

A/D

Clock

A/D

FIFO

RJ45

Ext Trigger and Clock

16-bit

A/D

D/A

Readback

Sigma-Deltas

0.1 Hz

* The external gate input signal is provided on

the DT9837A-OEM module.

Ext Gate*

Principles of Operation

Figure 20: Block Diagram of the DT9837A Module

Page 66

Chapter 5

4 mA Current

Source

+18 V Compliance Voltage

1 M

x1,

24-Bit

A/D

Control

Logic

4 mA

1 M

x1,

24-Bit

A/D

Tachometer

Input

4 mA

1 M

x1,

24-Bit

A/D

4 mA

1 M

x1,

24-Bit

A/D

Analog Input 0

Analog Input 1

Analog Input 2

Analog Input 3

High-

Speed

USB 2.0

Interface

USB

2.0

Ext Trigger

Tri gger

A/D

Clock

A/D

FIFO

RJ45

Ext Trigger and Clock

Sigma-Deltas

Ext Gate

0.5 Hz

Figure 21 shows a block diagram of the DT9837B module.

Figure 21: Block Diagram of the DT9837B Module

Page 67

Figure 22 shows a block diagram of the DT9837C module.

2 mA Current

Source

+18 V Compliance Voltage

1 M

x1, 10

24-Bit

A/D

Control

Logic

2 mA

1 M

24-Bit

A/D

2 mA

1 M

24-Bit

A/D

2 mA

1 M

24-Bit

A/D

Analog Input 0

Analog Input 1

Analog Input 2

Analog Input 3

24-Bit D/A

Sigma-

Delta

D/A

Clock

High-

Speed

USB 2.0

Interface

D/A

FIFO

USB

2.0

Ext Trigger

D/A

Output 0

Tri gger

A/D

Clock

A/D

FIFO

RJ45

Ext Trigger and Clock

Sigma-Deltas

x1, 10

1 Hz

40 kHz

Filter

Principles of Operation

Figure 22: Block Diagram of the DT9837C Module

Page 68

Chapter 5

Analog Input Features

This section describes the following features of analog input (A/D) subsystem on the DT9837 Series modules:

• Analog input channels, described on this page

• IEPE functions, described on page 69

• Input resolution, described on page 69

• Input ranges and gains, described on page 69

• Input sample clock sources, described on page 69

• Analog input conversion modes, described on page 70

• Input triggers, described on page 73

• Data format and transfer, described on page 75

• Error conditions, described on page 75

Analog Input Channels

The DT9837 Series modules support four, single-ended analog input channels (numbered 0 to

3). All analog input channels are simultaneously clocked. If desired, you can connect IEPE sensors to these inputs; refer to page 69 for more information on IEPE functions.

Note: To maintain simultaneous operation, all analog input connections must have the same lead lengths.

The DT9837 Series modules use Delta-Sigma analog-to-digital converters (ADCs) that provide anti-aliasing filters based on the clock rate. These filters remove aliasing, which is a condition where high frequency input components erroneously appear as lower frequencies after sampling.

DT9837 Series modules can acquire a single value from a single analog input channel, a single value from all the analog input channels simultaneously, or multiple values from a group of analog input channels. You can also read data from the following channels if supported by your module:

• Tachometer counter 0 – Supported on the DT9837, DT9837A, DT9837A-OEM, and DT9837B modules

• Tachometer counter 1 – Supported on the DT9837A, DT9837A-OEM, and DT9837B modules

• Gate counter 2 – Supported on the DT9837A-OEM and DT9837B modules

• Analog output readback channel – Supported on the DT9837A module

Refer to“Analog Input Conversion Modes” on page 70 for more information on specifying and reading data from these channels.

Page 69

Input Ranges and Gains

The DT9837 Series modules provide an input range of ±10 V and software-selectable gains of 1 and 10. This provides effective input ranges of ±10 V (when the gain is 1) and ±1 V (when the gain is 10).

IEPE Functions

Applications that require accelerometer, vibration, noise, or sonar measurements often use IEPE

sensors. IEPE conditioning is built-in to the analog input circuitry of the DT9837 Series

modules. The modules support the following software-programmable IEPE functions for each of the four analog inputs:

• Excitation current source – The DT9837, DT9837A, and DT9837B modules provide an internal excitation current source of 4 mA. The DT9837C module provides an internal excitation current source of 2 mA. You can enable or disable the use of a internal excitation current source using software. By default, the excitation current source is disabled.

• Coupling type – You can select whether AC coupling or DC coupling is used. By default, DC coupling is selected for the DT9837, DT9837A, and DT9837C modules, and AC coupling is selected for the DT9837B module.

Principles of Operation

Note: If you enable the use of the internal excitation current source, it is recommended that you choose AC coupling.

The DT9837C also provides a 1 Hz high-pass filter.

You can change the IEPE settings using the Open Layers Control Panel applet, described on

page 36, or by writing to the registers of the module, as described on Appendix C starting on page 135. For information on wiring IEPE inputs, refer to page 44.

For the DT9837A, you can also use the Control Panel to keep the module’s high-power circuitry always turned on to minimize any settling time errors related to the IEPE current source. Refer to page 36 for more information.

Input Resolution

The resolution of the analog input channels is fixed at 24 bits; you cannot specify the resolution in software.

Input Clock Source

The DT9837 Series modules support an internal clock, which is derived from the USB clock.

Use software to specify the internal clock source and the frequency at which to pace the input and output operations and to start the sample clock. For the DT9837 and DT9837A, the sampling frequency ranges from 195.3 Hz to 52.734 kHz. For the DT9837B and DT9837C, the sampling frequency ranges from 195.3 Hz to 105.469 kHz.

Page 70

Chapter 5

Note: According to sampling theory (Nyquist Theorem), specify a frequency that is at least twice as fast as the input’s highest frequency component. For example, to accurately sample a 20 kHz signal, specify a sampling frequency of at least 40 kHz to avoid aliasing.

The modules support a wide pass band of 0.5 Hz (0.1 Hz for the DT9837A) to 25.8 kHz (0.49 x sampling frequency) to eliminate aliasing, allowing you to measure low frequency signals accurately at the Nyquist sampling rate.

The actual frequency that the module can achieve may be slightly different than the frequency you specified due to the accuracy of the clock. You can determine the actual clock frequency using software.

Internally, the value that you specify for the internal clock frequency is multiplied by 512 (for frequencies of 52.734 kHz or less) or 256 (for frequencies greater than 52.734 kHz) to set the oscillator on the module. For example, if you specify an internal clock frequency of 50 kHz, the module sets the internal oscillator for the A/D converters to 25.6 MHz. The maximum timebase is 27 MHz.

Once the sample clock is started, the module requires 39 clock pulses before the first A/D conversion is completed (39/sample rate) due to the group delay of the converters. The software automatically adjusts for the group delay to provide only valid data in each buffer.

The tachometer data (which does not have the 39 sample group delay) is synchronized with the analog data stream. This is done through the firmware and device driver by caching the tachometer data and aligning it in time with the analog data in the user’s data buffers.

Analog Input Conversion Modes

DT9837 Series modules support single-value, single-values, and continuous scan conversion modes. This section describes each of these conversion modes.

Single-Value Operations

Single-value operations are simpler to use than continuous operations. Using software, you specify the analog input channel (0, 1, 2, or 3) and the gain that you want to use. The module acquires the data from the specified channel and returns the data immediately.

For single-value operations, you cannot specify a clock source, trigger source, scan mode, or buffer. Single-value operations stop automatically when finished; you cannot stop a single-value operation.

Note: You cannot read the value of tachometer counter 0 (described on page 82), tachometer counter 1 (described on page 84), gate counter 2 (described on page 85), or the analog output readback channel (described on page 79) using a standard single-value operation. To read these values, specify the channels as part of the analog input channel list using continuous scan mode, described on page 71.

Page 71

Principles of Operation

Single-Values Operations

If you prefer to read a single value from all the analog input channels simultaneously using one software call, use a single-values operation. You specify the analog input subsystem and the gain that you want to use for the channels (not the channels themselves). The module then acquires a value from each input channel simultaneously; the data is returned as an array of input values.

Note: For the DT9837, a single values operation also returns a valid value from tachometer counter 0 (analog input channel 4), described on page 82.

For the DT9837A and DT9837B, a single values operation returns values from the analog input channels as well as from tachometer counter 0 (described on page 82), tachometer counter 1 (described on page 84), gate counter 2 (described on page 85), and the analog output readback channel (for the DT9837A; described on page 79), but only the data from analog input channels 0 through 3 is valid. Use continuous scan mode, described next, to read valid data from the tachometer counters, gate counter, and analog output readback channel.

For single-values operations, you cannot specify a clock source, trigger source, scan mode, or buffer. Single-values operations stop automatically when finished; you cannot stop a single-values operation.

Continuous Scan Mode

Continuous scan mode takes full advantage of the capabilities of the DT9837 Series modules. You can specify a channel list, clock source, start trigger, reference trigger, post-trigger scan count, and buffer using software.

On the DT9837 module, you can enter up to 5 entries in the channel list, including four analog input channels (A/D channel 0 to 3) and tachometer counter 0 (A/D channel 4), described on

page 82.

On the DT9837A module, you can enter up to 8 entries in the channel list, including four analog input channels (A/D channels 0 to 3), tachometer counter 0 (A/D channel 4), described on page 82, tachometer counter 1 (A/D channel 5), described on page 84, gate counter 2 (A/D channel 6), described on page 85, and the analog output readback value (A/D channel 7), described on page 79. Using software, specify the channels you want to sample in sequential order.

On the DT9837B module, you can enter up to 7 entries in the channel list, including four analog input channels (A/D channels 0 to 3), tachometer counter 0 (A/D channel 4), described on page 82, tachometer counter 1 (A/D channel 5), described on page 84, and gate counter 2 (A/D channel 6), described on page 85. Using software, specify the channels you want to sample in sequential order.

On the DT9837C module, you can enter up to 4 entries in the channel list (analog input 0 to 3). Using software, specify the channels you want to sample in sequential order.

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When it detects the start trigger, the module samples all the channels in the list simultaneously.

If a reference trigger is not specified, data that is acquired after the start trigger is post-trigger data. The sampled data is placed in the allocated buffer(s). The operation continues until you stop it or until no more buffers are available.

If a reference trigger is specified, data that is acquired after the start trigger is pre-trigger data; when the reference trigger occurs, pre-trigger data acquisition stops and post-trigger acquisition starts at the next sample. The sampled data is placed in the allocated buffer(s). The operation continues until the number of scans that you specify for the post-trigger scan count have been acquired; at the point, the operation stops. Note that the sample at which the trigger occurs is not counted as a post-trigger sample. Refer to page 73 for more information about triggers.

The conversion rate is determined by the frequency of the input sample clock; refer to page 69 for more information about the input sample clock.

Using software, you can stop a scan by performing either an orderly stop or an abrupt stop. In an orderly stop, the module finishes acquiring the current buffer, stops all subsequent acquisition, and transfers the acquired data to host memory; any subsequent triggers are ignored. In an abrupt stop, the module stops acquiring samples immediately; the current buffer is not completely filled, it is returned to the application only partially filled, and any subsequent triggers are ignored.

To select continuous scan mode, use software to specify the following parameters:

• Specify the data flow as Continuous

• Specify the clock source as internal and specify the clock frequency (refer to page 69)

• Specify the start trigger (refer to page 73)

• Specify the reference trigger (refer to page 74).

• Specify the post-trigger scan count (the number of post-trigger samples to acquire after the reference trigger occurs).

Figure 23 illustrates continuous scan mode (using a start and reference trigger) with a channel

list of four entries: channel 0 through channel 3. In this example, pre-trigger analog input data is acquired when the start trigger is detected. When the reference trigger occurs, the specified number of post-trigger samples (3, in this example) are acquired.

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Figure 23: Continuous Scan Mode on the DT9837 Series Modules

Chan 0

Chan 1

Chan 2

Input

Sample

Clock

Chan 0

Chan 1

Chan 2

Chan 0

Chan 1

Chan 2

Chan 0

Chan 1

Chan 2

Start Trigger occurs

Reference Trigger occurs

3 Post-trigger samples acquired

Pre-trigger data acquired

Chan 0

Chan 1

Chan 2

Post-Trigger Scan Count = 3

Chan 0

Chan 1

Chan 2

Trigger Sample is not counted

as post-trigger sample

Using a Start and Reference Trigger

Principles of Operation

Input Triggers

A trigger is an event that occurs based on a specified set of conditions.

On the DT9837 Series modules, you can specify a start trigger source and a reference trigger source. Pre-trigger data acquisition starts when the start trigger event occurs. When the reference trigger event occurs, pre-trigger data acquisition stops and post-trigger acquisition starts. Post-trigger acquisition stops when the number of samples you specify for the post-trigger scan count has been reached. Refer to page 71 for more information.

Start Trigger Sources

The DT9837 Series modules support the following sources for the start trigger:

• Software trigger – A software trigger event occurs when you start the analog input operation (the computer issues a write to the module to begin conversions). Using software, specify the start trigger source as a software trigger.

• External digital (TTL) trigger – An external digital (TTL) trigger event occurs when the module detects a rising-edge transition on the signal connected to the Ext Trig connector on the module. Using software, specify the start trigger source as an external, positive digital (TTL) trigger.

Note: On the DT9837A, DT9837B, and DT9837C modules, if you configure the synchronization mode as slave, the RJ45 connector accepts trigger and clock signals from the master; you cannot use the Ext Trig connector on the slave module. Refer to page 87 for more information.

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• Analog threshold trigger – For the DT9837 module, the start trigger event occurs when the signal attached to analog input channel 0 rises above 1.0 V (the fixed threshold level). Using software, specify the start trigger source as a positive threshold trigger, and the threshold trigger channel as channel 0.

For the DT9837A and DT9837B modules, the start trigger event occurs when the signal attached to analog input channel 0 rises above a user-specified threshold value. Using software, specify the start trigger source as a positive threshold trigger, the threshold trigger channel as channel 0, and the threshold level as a value between 0.2 V and 9.8 V.

For the DT9837C module, the start trigger event occurs when the signal attached to a specified analog input channel in the channel list rises above or falls below a user-specified threshold value. Using software, specify the following parameters:

− Start trigger source – Specify a positive (low-to-high transition) threshold trigger if you

want to trigger when the signal rises above a threshold level, or a negative (high-to-low transition) threshold trigger if you want to trigger when the signal falls below a threshold level.

− Threshold channel – Specify any one of the analog input channels that are included in

the channel list as the threshold input channel.

− Threshold level – Specify a value between ±10 V for a gain of 1 or ±1 V for a gain of 10

as the threshold level.

Note: On the DT9837A, DT9837B, and DT9837C modules, if you configure the synchronization mode as slave, the RJ45 connector accepts trigger and clock signals from the master; you cannot use the analog threshold trigger on the slave module. Refer to page

87 for more information.

Reference Trigger Sources

DT9837 Series modules support an analog threshold trigger for the reference trigger.

The reference trigger event occurs when the signal attached to a specified analog input channel in the channel list rises above or falls below a user-specified threshold value. Using software, specify the following parameters:

• Reference trigger source – Specify a positive (low-to-high transition) threshold trigger if you want to trigger when the signal rises above a threshold level, or a negative (high-to-low transition) threshold trigger if you want to trigger when the signal falls below a threshold level.

• Threshold channel – Specify any one of the analog input channels that are included in the channel list as the threshold input channel.

• Threshold level – Specify a value between ±10 V for a gain of 1 or ±1 V for a gain of 10 as the threshold level.

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Data Format and Transfer

DT9837 Series modules use offset binary data encoding, where 000000 represents negative full-scale, and FFFFFFh represents positive full-scale. Use software to specify the data encoding as binary. The ADC outputs FFFFFFh for above-range signals, and 000000 for below-range signals.

Before you begin acquiring data, you must allocate buffers to hold the data. A Buffer Done event is returned whenever a buffer is filled. This allows you to move and/or process the data as needed.

We recommend that you allocate a minimum of two buffers for continuous analog input operations. Data is written to multiple allocated input buffers continuously; when no more empty buffers are available, the operation stops. The data is gap-free.

Note: The DT9837A and DT9837 C modules have an input FIFO of 2 kBytes; the DT9837B has an input FIFO of 4 kBtyes; and the DT9837 does not use an input FIFO.

Principles of Operation

Error Conditions

DT9837 Series modules report any overrun errors by sending an overrun event to the application program. This event indicates that data buffers are not being sent from the module to the host fast enough, and the A/D converter ran out of buffers. To avoid this error, try one or more of the following:

• Reduce the clock rate of the A/D

• Increase the size of the buffers

• Increase the number of buffers

• Close any other applications that are running

• Run the program on a faster computer

If one of these error conditions occurs, the module stops acquiring and transferring data to the host computer.

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Analog Output Features

This section describes the following features of analog output operations:

• Analog output channels, described below

• Output ranges and gains, described below

• Output resolution, described on page 76

• Output conversion mode, described on page 77

• Output clocks, described on page 76

• Output triggers, described on page 80

• Data format and transfer, described on page 80

• Error conditions, described on page 81

Analog Output Channels

The DT9837, DT9837A, and DT9837C modules support one analog output channel through analog output subsystem 0. Note that on the DT9837A module, you can read back the value of the analog output channel through the analog input channel list; refer to page 79 for more information.

The DT9837 and DT9837A modules provide a two-pole, 10 kHz Butterworth filter and the DT9837C provides a 40 kHz smoothing filter to prevent noise from interfering with the output signal.

The analog output channel powers up to a value of 0 V ±10 mV.

Output Ranges and Gains

The DT9837 and DT9837A modules can output bipolar analog output signals in the range of ±10 V, with a gain of 1.

The DT9837C module can output bipolar analog output signals in the range of ±3 V, with a gain of 1.

Output Resolution

The resolution of the analog output channel is fixed at 24-bits; you cannot specify the resolution in software.

Output Clocks

The output clock on the DT9837, DT9837A, and DT9837C modules is derived from the USB clock to produce the output clock frequency.

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On the DT9837 module, the clock frequency is fixed at 46.875 kHz. On the DT9837A module, you can program the clock frequency to value between 10 kHz and 52.734 kHz. On the DT9837C module, you can program the clock frequency to value between 10 kHz and

96.0 kHz.Use software to specify an internal clock source and to specify the clock frequency for the analog output subsystem.

Internally, the value that you specify for the analog output clock frequency is multiplied by 512 to set the oscillator on the module. The maximum timebase for the DT9837 is 24 MHz; the maximum timebase for the DT9837A and DT9837C is 27 MHz.

Due to the group delay of the Delta-Sigma D/A converter, the DT9837 requires 34 clock pulses, while the DT9837A and DT9837C modules require 29 clock pulses once the analog output sample clock is started before the first D/A conversion is completed.

Output Conversion Modes

The DT9837, DT9837A, and DT9837C modules support single-value and waveform analog output operations. The DT9837A and DT9837C modules also support continuous analog output operations. This section describes each of these conversion modes.

Principles of Operation

Note: The DT9837A also provides the ability to read the value of the analog output channel in the analog input data stream. Refer to page 79 for more information.

Single-Value Mode

Single-value mode is the simplest to use but offers the least flexibility and efficiency. Use software to specify the analog output channel that you want to update, and the value to output from that channel. The value is output from the specified channel immediately.

For a single-value operation, you cannot specify a clock source, trigger source, or buffer. Single-value operations stop automatically when finished; you cannot stop a single-value operation.

Note: On the DT9837 module, ensure that no analog input operations are running before performing an analog output operation or an error will be reported.

Waveform Generation Mode

Waveform generation mode is supported on the DT9837, DT9837A, and DT9837C modules. In this mode, a waveform, which is specified in a single buffer, is output repetitively.

On the DT9837, allocate a buffer less than or equal to 8192 samples, and then fill the buffer with the waveform that you want to output. On the DT9837A and DT9837C modules, you can allocate a buffer of any size, and then fill the buffer with the waveform that you want to output.

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When it detects a software trigger, the host computer transfers the entire waveform pattern to the 8 kByte output FIFO on the module, and the module starts writing output values to the analog output channel at the specified clock rate. The module recycles the data, allowing you to output the same pattern continuously without any further CPU or USB bus activity.

When it reaches the end of the FIFO, the module returns to the first location of the FIFO and continues outputting the data. This process continues indefinitely until you stop it.

To select waveform generation mode, use software to specify the following parameters:

• Specify the data flow as Continuous

• Specify WrapSingleBuffer as True to use a single buffer

• Specify the clock source as internal and specify the clock frequency. Refer to page 76 for more information about the clock source and frequency.

• Specify a software trigger source, described in the next section

Note: On the DT9837, an error will be reported if you specify a buffer with greater than 8192 samples (the size of the output FIFO on the module).

If you want to output data from the analog output channel on the DT9837 module while acquiring analog input data, ensure that you set up and start the analog output operation before starting the analog input operation, or an error will be reported.

The DT9837, DT9837A, and DT9837C modules support the ability to mute the output voltage to 0 V. Muting the output does not stop the analog output operation; instead, the analog output voltage is reduced to 0 V over 1020 samples. When desired, you can unmute the output voltage to its current level. Refer to your software documentation for more information on muting and unmuting the output voltage.

Continuous Analog Output Operations

Continuous analog output operations are supported on the DT9837A module only. Use continuously paced analog output mode to continuously output buffered values to the analog output channel at a specified clock frequency. The DT9837A and DT9837C support the ability to start continuous analog output operations and continuous analog input operations simultaneously.

Use software to fill multiple output buffers with the values that you want to write to the analog output channel. When it detects the specified trigger, the module starts writing the values from the output buffer to the analog output channel at the specified clock frequency. The operation repeats continuously until either all the data is output from the buffers or you stop the operation.

Note: Make sure that the host computer transfers data to the output channel list fast enough so that the list does not empty completely; otherwise, an underrun error results.

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Principles of Operation

To select continuously paced analog output mode, use software to specify the following parameters:

• Specify the data flow as Continuous

• Specify WrapSingleBuffer as False to use multiple buffers

• Specify the clock source as internal and specify the clock frequency. Refer to page 76 for more information about the clock source and frequency.

• Specify the trigger source as any of the supported trigger sources. Refer to page 80 for more information about the supported trigger sources.

• To start the analog input and analog output operations simultaneously using the DT-Open Layers for .NET Class Library, use the SimultaneousStart.AddSubsystem, SimultaneousStart.PreStart, and SimultaneousStart.Start methods. Refer to the documentation for the DT-Open Layers for .NET Class Library for more information.

We recommend that you allocate a minimum of two buffers for a continuously paced analog output operation. Data is written from multiple output buffers continuously; when no more buffers of data are available, the operation stops. The data is gap-free.

The DT9837, DT9837A, and DT9837C modules support the ability to mute the output voltage to 0 V. Muting the output does not stop the analog output operation; instead, the analog output voltage is reduced to 0 V over 1020 samples. When desired, you can use unmute the output voltage to its current level. Refer to your software documentation for more information on muting and unmuting the output voltage.

To stop a continuously paced analog output operation, you can stop queuing buffers for the analog output system, letting the module stop when it runs out of data, or you can perform either an orderly stop or an abrupt stop using software. In an orderly stop, the module finishes outputting the specified number of samples, and then stops; all subsequent triggers are ignored. In an abrupt stop, the module stops outputting samples immediately; all subsequent triggers are ignored.

Reading the Analog Output Value in the Analog Input Data Stream (DT9837A Only)

On the DT9837A module, you can read back the value of the analog output channel in the analog input data stream. Specify channel 7 in the analog input channel list to read back the value of the analog output channel.

When the analog input operation is started, the value of the analog output channel is returned in the analog input data stream. (An analog value is returned.) The software automatically synchronizes the value of the analog output channel with the analog input measurements, so that all measurements are correlated in time.

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Output Trigger

The DT9837, DT9837A, and DT9837C modules support the following trigger sources for starting analog output operations:

• Software trigger – A software trigger event occurs when you start the analog output operation (the computer issues a write to the module to begin conversions). Using software, specify the trigger source for D/A subsystem 0 as a software trigger.

• External digital (TTL) trigger – This trigger source is supported on the DT9837A and DT9837C modules. An external digital (TTL) trigger event occurs when the module detects a rising-edge transition on the signal connected to the Ext Trig connector on the module. Using software, specify the trigger source for D/A subsystem 0 as an external, positive digital (TTL) trigger.

• Analog threshold trigger – This trigger source is supported on the DT9837A and DT9837C modules.

For the DT9837A module, an analog threshold trigger event occurs when the signal attached to analog input channel 0 rises above a user-specified threshold value. Using software, specify the trigger source as a positive threshold trigger, the threshold trigger channel as analog input channel 0, and the threshold level as a value between 0.2 V and

9.8 V.

For the DT9837C module, the analog threshold trigger event occurs when the signal attached to a specified analog input channel in the channel list rises above or falls below a user-specified threshold value. Using software, specify the following parameters:

− Start trigger source – Specify a positive (low-to-high transition) threshold trigger if you

want to trigger when the signal rises above a threshold level, or a negative (high-to-low transition) threshold trigger if you want to trigger when the signal falls below a threshold level.

− Threshold channel – Specify any one of the analog input channels that are included in

the channel list as the threshold input channel.

− Threshold level – Specify a value between ±10 V for a gain of 1 or ±1 V for a gain of 10

as the threshold level.

Note: If you configure the synchronization mode as slave, the RJ45 connector accepts trigger and clock signals from the master; you cannot use the Ext Trig connector on the slave module. Refer to page 87 for more information.

Data Format and Transfer

Data from the host computer must use offset binary data encoding for analog output signals, where 000000 represents −10 V, and FFFFFFh represents +10 V. Using software, specify the data encoding as binary.

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Error Conditions

The DT9837, DT9837A, and DT9837C modules report any underrun errors by sending an underrun event to the application. This event indicates that the data buffers are not being sent from the host to the module fast enough, and the D/A converter ran out of data. To avoid this error, try one or more of the following:

• Reduce the clock rate of the analog output operation

• For the DT9837, ensure that you allocate a single buffer with 8192 or fewer samples

• Close any other applications that are running

• Run the program on a faster computer

Principles of Operation

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Tachometer Input Features

You can connect a tachometer signal with a range of ±30 V to the DT9837, DT9837A, and DT9837B modules. (The DT9837C does not support a tachometer input.) On the DT9837, this signal has a maximum frequency of 380 kHz and a minimum pulse width of 1.3 μs. On the DT9837A and DT9837B modules, this signal has a maximum frequency of 1 MHz and a minimum pulse width of 0.4 μs. The threshold voltage is fixed at +2 V with 0.5 V of hysteresis.

You can measure the frequency or period of the tachometer input signal using tachometer counter 0. On the DT9837A and DT9837B modules, you can also measure the phase of the tachometer input signal in relation to the A/D sample using tachometer counter 1. These measurements are described in more detail in the following subsections.

Frequency or Period Measurements – Tachometer Counter 0

Use frequency or period measurements to calculate the rotation speed for high-level (±30 V) tachometer input signals. An internal 12 MHz counter (tachometer counter 0) is used for the measurement, yielding a resolution of 83 ns (1/12 MHz).

You can read the number of counts between two consecutive starting edges of the tachometer input signal by including channel 4 in the analog input channel list. On the DT9837 module, the starting edge is always rising; on the DT9837A and DT9837B modules, the starting edge is programmable (either rising or falling).

You can specify the following parameters for tachometer counter 0 using the Open Layers Control Panel applet, described on page 36, by using software commands, or by writing to the registers of the module, as described in Appendix C starting on page 135:

• The starting edge of the tachometer input signal to use for the measurement: rising edge or falling edge. On the DT9837 module, the starting edge is always the rising edge.

• The value read between measurements: either zero or the previous measurement value. On the DT9837 module, this value is always the previous measurement value.

• A flag (called Stale) indicating whether or not the data is new. If the Stale flag is set as Used, the most significant bit (MSB) of the value is set to 0 to indicate new data; reading the value before the measurement is complete returns an MSB of 1. If the Stale flag is set to Not Used, the MSB is always set to 0.

On the DT9837 module, the MSB is always 0 (Not Used).

When the operation is started, the internal 12 MHz counter starts incrementing when it detects the first starting edge of the tachometer input and stops incrementing when it detects the next starting edge of the tachometer input. When the measurement is complete, the counter/timer remains idle until it is read. On the next read, either 0 or the current value of the tachometer input (from the previous measurement operation) is returned depending on the module and the Control Panel settings, described above, and the next operation is started automatically.

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Principles of Operation

The software automatically synchronizes the value of the tachometer input with the analog input measurements, so that all measurements are correlated in time. The tachometer input is treated like any other channel in the analog input channel list; therefore, all the triggering and conversion modes supported for analog input channels are supported for the tachometer input.

When you read the value of the tachometer input as part of the analog input data stream, you might see results similar to the following (note that this assumes that the previous measurement value is returned between new measurement values):

Table 2: An Example of Reading the Tachometer Input as Part of the Analog Input Data Stream

Tachomete r

Time A/D Value

10 5002 0 Operation started, but is not complete

20 5004 0 Operation not complete

30 5003 0 Operation not complete

40 5002 12373 Operation complete

Input Value

Status of Operation

50 5000 12373 Next operation started, but is not complete

60 5002 12373 Operation not complete

70 5004 12373 Operation not complete

80 5003 14503 Operation complete

90 5002 14503 Next operation started, but is not complete

Using the count that is returned from the tachometer input, you can determine the following:

• Frequency of a signal pulse (the number of periods per second). You can calculate the frequency as follows:

− Frequency = 12 MHz/(Number of counts – 1)

where 12 MHz is the internal counter/timer clock frequency

For example, if the count is 21, the measured frequency is 600 kHz (12 MHz/20).

• Period of a signal pulse. You can calculate the period as follows:

− Period = 1/Frequency

− Period = (Number of counts – 1)/12 MHz

where 12 MHz is the internal counter/timer clock frequency

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Phase Measurements – Tachometer Counter 1

On the DT9837A and DT9837B modules, you can measure the phase of the tachometer input in relation to the A/D sample by reading tachometer counter 1. To read the value of this counter, specify channel 5 in the analog input channel list.

An internal 48 MHz clock (with 21 ns resolution) is used to calculate the measurement, which allows you to precisely correlate tachometer measurements with the analog input data.

You can specify the following parameters for tachometer counter 1 using the Open Layers Control Panel applet, described on page 36, or by writing to the registers of the module, as described in Appendix C starting on page 135:

• The signal that starts the measurement: A/D sample, rising edge of the tachometer input signal, or falling edge of the tachometer input signal

• The signal that stops the measurement: A/D sample, rising edge of the tachometer input signal, or falling edge of the tachometer input signal

Note: Note that if you choose to start the measurement using the A/D sample, choose a tachometer edge to stop the measurement. Likewise, if you choose to stop the measurement using the A/D sample, choose a tachometer edge to start the measurement.

• The value of the Self-Clear flag, which determines the value that is read between measurements (either 0 or the previous measurement value)

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Gate Input Features

The DT9837A-OEM module provides a 4-pin gate input connector for connecting a TTL gate input signal; see page 133 for connector pin assignments. The DT9837B module provides a BNC connector for connecting a gate input signal.

You can read the value of gate counter 2 to measure the time between the following signals:

• Completion of the A/D sample to the rising or falling edge of the gate input signal

• Rising or falling edge of the gate input signal to the rising or falling edge of the gate input signal, which you can use to determine the pulse width of the gate signal

• Rising or falling edge of the gate input signal to the completion of the A/D sample

For these measurements, specify channel 6 in the analog input channel list. An internal 48 MHz clock (with 21 ns resolution) is used for the measurements, which allows you to precisely correlate analog input data with measurements from the gate input signal.

You can specify the following parameters for gate counter 2 using the Open Layers Control Panel applet, described on page 36, or by writing to the registers of the module, as described in Appendix C starting on page 135:

Principles of Operation

• The signal that starts the measurement: A/D sample, gate rising edge, or gate falling edge

• The signal that stops the measurement: A/D sample, gate rising edge, or gate falling edge

Note: Note that if you choose to start the measurement using the A/D sample, choose a gate input edge to stop the measurement. Likewise, if you choose to stop the measurement using the A/D sample, choose a gate input edge to start the measurement.

If you choose the start and stop the measurement using the same gate edge, be aware that the stopping edge does not restart the measurement; the next starting edge will start the next measurement.

• The value of the Self-Clear flag, which determines the value that is read between measurements (either 0 or the previous measurement value)

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Host PC

DT9837

Series #1

USB

Port 1

DT9837

Series #2

USB

Port 2

DT9837

Series #n

USB

Port n

. . .

Device Under

Test

External

Tri gger

Inputs

Triggering Acquisition on Multiple Modules

Note: For DT9837A, DT9837B, and DT9837C modules, you can synchronize acquisition on multiple modules using the RJ45 (LVDS) synchronization connector, described on page 87.

The internal clock on the DT9837, DT9837A, and DT9837C modules when the synchronization mode is none (see page 87), is derived from the USB clock and provides the timing for both the analog input and analog output subsystems on the module.

You can start acquisition on multiple modules by connecting all modules to a shared external trigger input, as shown in Figure 24. When triggered, the modules start acquiring data at the same time.

Using this connection scheme, the measurements of one module may not be synchronous with the measurements of another module due to logic delays in the clocking and USB circuitry.

Figure 24: Triggering Multiple Modules Using an External Trigger Source

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Principles of Operation

Synchronizing Acquisition on Multiple DT9837A, DT9837B, or DT9837C Modules

DT9837A, DT9837B, and DT9837C modules provide an RJ45 (LVDS) synchronization connector that you can use to connect and synchronize multiple DT9837A, DT9837B, or DT9837C modules. In this scheme, one module is the master and the other modules are the slave. You specify the synchronization mode (master, slave, or none) of the RJ45 connector using software.

When configured as a master, the RJ45 synchronization connector outputs trigger and clock signals. When configured as a slave, the RJ45 connector accepts trigger and clock signals from the master; you cannot use the Ext Trig connector or the analog threshold trigger on the slave module in this configuration. When configured as none (the default mode), the DT9837A, DT9837B, or DT9837C module uses the USB clock instead of the RJ45 synchronization connector. The synchronization mode remains set until changed or until the application exits.

You can connect multiple modules in one of two ways. Figure 25 shows how to connect a maximum of two DT9837A, DT9837B, or DT9837C modules by daisy chaining them together through the RJ45 connector. Figure 26 shows how to connect a maximum of four DT9837A, DT9837B, or DT9837C modules by using an RJ45 distribution panel, such as the EP386, where the panel contains four RJ45 connectors that are wired in parallel.

If you have revision G or earlier of the DT9837A or revision E or earlier of the DT9837A-OEM, you can attach a maximum of two modules together.

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Host PC

DT9837A,

DT9837B, or

DT9837C

Master

Device

Under Test

External

Tri gger

Inputs

RJ45 (LVDS)

Inputs

USB

Port 2

USB

Port 1

USB

DT9837A,

DT9837B, or

DT9837C

Slave

Device

Under Test

External

Tri gger

Inputs

RJ45 (LVDS)

USB

Port 2

Inputs

Host PC

USB

Port 1

Inputs

USB

Port 3

USB

Port 4

RJ45 (LVDS)

USB

EP386

RJ45 Distribution

Panel (connectors

wired in parallel)

* The RJ45 cables must be less than 1 foot in length. For minimum clock skew, the master module must be less than 4 inches away from the RJ45 distribution panel.

DT9837A,

DT9837B, or

DT9837C

Slave

DT9837A,

DT9837B, or

DT9837C

Slave

DT9837A,

DT9837B, or

DT9837C

Slave

DT9837A,

DT9837B, or

DT9837C

Master

Figure 25: Synchronizing Two DT9837A, DT9837BB, or DT9837C Modules by Daisy Chaining the

RJ45 Connectors (Shown Using an External Trigger)

Figure 26: Synchronizing Four DT9837A, DT9837B, or DT9837C Modules Using the EP386

RJ45 Distribution Panel (Shown Using an External Trigger)

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Principles of Operation

When synchronizing multiple modules, start the slave modules before starting the master module. When the master module is triggered (using any of the supported trigger sources), both the master and the slave modules start acquiring data at the same time (within one A/D conversion of the clock). Note that you can set the clock rate to be the same or different on each module.

Note: It is important that you start the slave modules first, followed by the master module so that the slave receives the appropriate clock and trigger signals from the master.

If you start the master module before the slaves, the slaves never start; you will see a delay of approximately 20 seconds if you try to stop or abort the analog input operation on a slave module that is waiting for a trigger.

If you are using multiple DT9837C modules and want to trigger the master module with an external TTL trigger, you must set both the master and the slave modules to use the external TTL trigger for proper operation (no physical trigger connection to the slave is required).

When you stop the master module, the slaves continue to run and return data until you stop the analog input subsystem on the slave modules. Be sure to stop the analog input subsystems on all DT9837A, DT9837B, or DT9837C modules before disconnecting the cable from the RJ45 connectors.

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Chapter 5

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Supported Device Driver Capabilities