Measurement DAC488 v.1 User Manual

DAC488

User's Manual

12-Bit Digital-to-Analog Converter Systems; Models DAC488/2 and DAC488/4

the smart approach to instrumentation ™

IOtech, Inc.

25971 Cannon Road

Cleveland, OH 44146-1833

Phone: (440) 439-4091

Fax: (440) 439-4093 E-mail: sales@iotech.com Internet: www.iotech.com

DAC488

12-Bit Digital-to-Analog Converter Systems

Models DAC488/2 and DAC488/4

Released Per EO#1927R11

User's Manual

107-0901

p/n

Rev.

1.0

Warranty

Your IOtech warranty is as stated on the product warranty card. You may contact IOtech by phone, fax machine, or e-mail in regard to warranty-related issues. Phone: (440) 439-4091, fax: (440) 439-4093, e-mail: sales@iotech.com

Limitation of Liability

IOtech, Inc. cannot be held liable for any damages resulting from the use or misuse of this product.

All IOtech documentation, software, and hardware are copyright with all rights reserved. No part of this product may be copied, reproduced or transmitted by any mechanical, photographic, electronic, or other method without IOtech’s prior written consent. IOtech product names are trademarked; other product names, as applicable, are trademarks of their respective holders. All supplied IOtech software (including miscellaneous support files, drivers, and sample programs) may only be used on one installation. You may make archival backup copies.

FCC Statement

IOtech devices emit radio frequency energy in levels compliant with Federal Communications Commission rules (Part 15) for Class A devices. If necessary, refer to the FCC booklet How To Identify and Resolve Radio-TV Interference Problems (stock # 004-000-00345-4) which is available from the U.S. Government Printing Office, Washington, D.C. 20402.

CE Notice

Many IOtech products carry the CE marker indicating they comply with the safety and emissions standards of the European Community. As applicable, we ship these products with a Declaration of Conformity stating which specifications and operating conditions apply.

Warnings and Cautions

Refer all service to qualified personnel. This caution symbol warns of possible personal injury or equipment damage under noted conditions. Follow all safety standards of professional practice and the recommendations in this manual. Using this equipment in ways other than described in this manual can present serious safety hazards or cause equipment damage.

This warning symbol is used in this manual or on the equipment to warn of possible injury or death from electrical shock under noted conditions.

This ESD caution symbol urges proper handling of equipment or components sensitive to damage from electrostatic discharge. Proper handling guidelines include the use of grounded anti-static mats and wrist straps, ESD-protective bags and cartons, and related procedures.

Calibration Notice

As applicable, IOtech calibrates its hardware products to published specifications. Periodic hardware calibration is not covered under the warranty and must be performed by qualified personnel as specified in this manual. Improper calibration procedures may void the warranty.

Quality Notice

IOtech has maintained ISO 9001 certification since 1996. Prior to shipment, we thoroughly test our products and review our documentation to assure the highest quality in all aspects. In a spirit of continuous improvement, IOtech welcomes your suggest i ons.

Introduction to this Manual

This manual covers the setup and operation of the DAC488/4 and the DAC488/2 digital-to-analog converter systems. This manual is organized as follows:

• Chapter 1 - DAC488 Overview gives an overview of the basic features of a DAC488 system. DAC488

accessories and specifications are also provided.

• Chapter 2 - DAC488 Setup explains in detail the various hardware features of the DAC488 unit.

• Chapter 3 - DAC488 Power & Assembly provides detailed instructions on line-voltage selection and

fuse replacement, rack-mount and bench-top installation, as well as power-up activation.

• Chapter 4 - DAC488 Operation explains the DAC488 theory of operation. Descriptions of the

DAC488 command groups, triggering, internal buffer, control modes, as well as IEEE 488 bus support, are provided.

• Chapter 5 - IEEE 488 Background describes the history and the basic concepts of IEEE 488

operation, including the various IEEE 488 bus commands and bus lines.

• Chapter 6 - DAC488 Calibration explains the manual and automatic procedures for calibrating the

DAC488 unit.

• Chapter 7 - DAC488 Commands discusses the entire command set covering the DAC488/4 and

DAC488/2 units. The command syntax, groups, and reference are provided. The description format of the individual commands includes the command type, syntax, description, and an example program excerpt.

• Chapter 8 - Troubleshooting provides a reference for possible solutions to technical problems. Before

calling for technical assistance, refer to this chapter.

•

The Appendix provides background information concerning the IEEE 488 bus, the serial bus, and ASCII controls.

• The Index provides a comprehensive alphabetical listing of the main terms and topics in this manual.

Also, the Abbreviations on the last pages of this manual, provides an overall list of abbreviations, including acronyms and ASCII control codes, as an additional reference for this manual and for other related literature.

CAUTION

CAUTIONCAUTION

Using this equipment in ways other than described in this manual can cause personal injury or equipment damage. Before setting up and using your equipment, you should read all documentation that covers your system. Pay special attention to cautions and warnings formatted like this one.

DAC488 User’s Manual i

1 - DAC488 Overview

Introduction…… 1 Accessories…… 2 Specifications…… 2

Digital I/O…… 2 Analog Output…… 3 IEEE 488…… 3 General…… 4

2 - DAC488 Setup

The Package…… 5 Hardware Setup…… 6

Front & Rear Panel Layouts…… 6 Default Settings…… 7 IEEE 488 Bus Address Selection…… 7 Mode Selection…… 7 Analog Output Ports…… 7 Digital I/O Port…… 8

Transistor-Transistor Logic (TTL) Lev el s…… 9 High Voltage/High Current Digital Outputs…… 9 External Trigger/SRQ Input…… 11 To Configure the Digital Output Lines…… 11

3 - DAC488 Power & Assembly

Introduction…… 13

Internal Components…… 13 Factory Service…… 13

Power Line & Fuse Configuration…… 14

Line Voltage Selection…… 14

To Select the Line Voltage…… 15

Fuse Replacement…… 16

To Replace the Fuse…… 16

Rack-Mount & Bench-Top Assembly…… 17

Rack Mount…… 17 Bench Top…… 17

Power-Up & Performance Tests…… 18

Power-Up Activation…… 18 Programming Examples……19

KYBDCTRL.BAS Program…… 19 To Run the Keyboard Controller Program…… 19 DAC488 Command Responses…… 20

Performance Verification…… 20

To Verify the Port Volt age - 10-V ol t Range…… 21 To Verify the Port Voltage - 5-Volt Range…… 21 To Verify the Port Voltage - 1-Volt Range…… 22 Data Transfer Speeds…… 22

4 - DAC488 Operation

Introduction…… 23 Command Groups…… 23

System & Port Commands…… 23 Command Support…… 24

Port Triggering…… 24

Trigger Processing & Trigger Overrun…… 25

Internal Buffer…… 26

Buffer Data…… 26 Buffer Save-and-Restore Program…… 27

Control Modes…… 28

Direct Control Mode…… 28 Indirect Control Mode……28 Stepped Control Mode…… 28 Waveform Control Mode…… 29

Multiple Port Synchronization…… 30

Synchronized Waveforms Program…… 30

Digital I/O Port…… 32 User-Defined System Defaults…… 33 IEEE 488 Bus Support…… 33

Bus Lines…… 33 Bus Commands…… 34 Bus Addresses…… 34 Bus Terminators…… 34

5 - IEEE 488 Background

History…… 35 General Bus Structure…… 35 Bus Lines & Bus Commands…… 36

Bus Management Lines…… 36 Handshake Lines…… 37 Data Transfer Lines…… 37 Bus Command Groups…… 38 More On Service Requests…… 39

6 - DAC488 Calibration

Introduction…… 41 Calibration Procedures…… 41

Manual Calibration Procedure…… 42

Part I: Connections & Preparations…… 42 Part II: Acquiring the Gain Calibration

Constants…… 42

Part III: Acqui ri ng t he Offset Calibration

Constant…… 43

BASIC Calibration Program…… 43 Automatic Calibration Procedure…… 47

Part I: Connections & Preparations…… 47 Part II: Automatic Calibration Process…… 48 Part III: Automatic Cal i bration Report…… 49

ii DAC488 User’s Manual

7 - DAC488 Commands

A - Appendix

Introduction…… 51 Command Syntax…… 51 Command Groups…… 53

System Commands…… 53 Port Commands…… 53 Command Support……53

Command Summary…… 54 Command Reference…… 57

@ - Trigger On Command…… 58 A - Autorange…… 59 B - Buffer Data…… 60 C - Control Mode…… 61 D - Digital Output…… 63 E? - Query Error Status…… 64 F - Buffer Definition…… 66 G - GET Trigger Mask…… 67 H - Offset Calibration…… 68 I - Interval…… 69 J - Gain Calibration…… 70 K - End-Or-Identify Control…… 71 L - Buffer Location…… 72 M - Service Request Mask…… 73 N - Number of Cycles…… 74 O - Output Format…… 75 P - Port Select…… 76 Q - External Trigger Mask…… 77 R - Range Select…… 78 S - System Defaults…… 79 T - Command Trigger Mask…… 80 U - User Status…… 81 V - Value Output…… 84 W - Test…… 85 X - Execute…… 86 Y - Bus Terminator…… 87 ? - Query…… 88 Serial Poll Status Byte…… 89

IEEE 488 Bus & Serial Bus Lines…… 93 IEEE 488 Bus Commands…… 94 ASCII Codes…… 95

ASCII Code Summary…… 95

Decimal Values 00 to 63 - ACG, UCG & LAG……

Decimal Values 64 to 127 - TAG & SCG…… 96

ASCII Code Details…… 97

Decimal Values 00 to 31 - ACG & UCG

Characteristics…… 97

Decimal Values 00 to 31 - ACG & UCG

Descriptions…… 98 Decimal Values 32 to 63 - LAG…… 99 Decimal Values 64 to 95 - TAG…… 100 Decimal Values 96 to 127 - SCG…… 101

Index…… 103 Abbreviations…… 106

8 - Troubleshooting

Radio Interference Problems…… 91 Electrostatic Discharge (ESD) Damage…… 91 Other Issues…… 91

Power-Up Activation…… 91 Trigger Processing & Trigger Overrun…… 92 Query Error Status…… 92

DAC488 User’s Manual iii

−

Notes

iv DAC488 User’s Manual

DAC488 Overview 1

Introduction…… 1 Accessories…… 2 Specifications…… 2

Digital I/O…… 2 Analog Output…… 3 IEEE 488…… 3 General…… 4

Introduction

The DAC488 is a multiple output Digital-to-Analog Converter (DAC) interface for the IEEE 488 bus. Each port uses a 12-bit plus-sign D/A converter and is isolated from IEEE common and the other ports by up to 500 volts. Each port can be programmed for full-scale output of ±1 volt, ±5 volts and ±10 volts. Voltage values may be specified in volts or bits in increments of 1 part in 4096 plus-sign. The resolution of the ranges is 250 µVolts, 1.25 mVolts and 2.5 mVolts respectively.

Four operational modes are available to allow each port to be controlled directly from the IEEE bus or in an automatic manner. An internal 8,191 sample buffer is included which can be loaded with waveform voltages. These voltages may then be output in sequence either on a periodic interval or in a triggered fashion. The DAC488 sample buffer is automatically saved in Non-Volatile RAM (NV-RAM) as it is loaded, allowing a once only configuration of the device for many applications. All configuration settings may also be saved in Non-Volatile RAM for use as the permanent defaults.

Each of the ports can be triggered from three different sources: An external trigger, a trigger command, or a Group Execute Trigger ( trigger sources may be selected for each port.

GET) bus command. Since each port can be triggered independently, different

The interface also provides 8 TTL level digital inputs and 8 digital outputs. The digital outputs may be internally configured as either TTL level or 100 mA outputs to allow interfacing with solenoids, relays or other devices. An external trigger/SRQ input is also provided which can trigger the interface or generate an SRQ on either a falling or rising edge of a TTL compatible signal. All digital signals as well as +5 Volts and ground are accessible via a 20-pin card edge connector (Standard version) or a DB25 pin connector (CE version) located on the rear panel.

Calibration may be done automatically by connecting the interface to a Keithley Model 199 DMM. No mechanical adjustments are required. After calibration, a complete calibration report will be printed if the interface is connected to an IEEE printer.

Throughout this manual, the term “DAC488” refers to either a DAC488/4 or a DAC488/2.

DAC488 User’s Manual DAC488 Overview 1

Accessories

Additional accessories that can be ordered for the DAC488 include:

• CA-1: Power Cable

• CA-7-1: 1.5 foot IEEE 488 Cable

• CA-7-3: 6 foot shielded IEEE 488 Cable

• CA-7-4: 6 foot reverse entry IEEE 488 Cable

• CA-8-20: 6 foot, 20 conductor ribbon cable with a card edge connector on one end, the other end

• CA-35-2: 2 foot, DB25 male-to-female pin Connector

• CA-35-6: 6 foot, DB25 male-to-female pin Connector

• CN-40-12: DAC488 Analog Output Connector

• CN-6-20: 20-pin card edge Connector.

• CN-20: Right Angle IEEE 488 adapter, male and female

• CN-22: IEEE 488 multi-tap bus strip, four female connectors in parallel

• CN-23: IEEE 488 panel mount feed-through connector, male and female

Specifications

unterminated.

Please read this manual carefully! If equipment is used in any manner not specified in this manual, the protection provided by the equipment may be impaired.

CAUTION

CAUTIONCAUTION

Digital I/O

WARNING

WARNINGWARNING

Do not use the DAC488 unit outdoors! This unit is intended for indoor use only! Unexpected outdoor conditions could result in equipment failure, bodily injury or death!

Terminal Installation Category: Standard: Not Applicable. CE: Category 1. Transistor-Transist or Logic (TTL) Leve ls: Digital outputs will drive 2 TTL loads or sink 100mA

(selectable using internal configuration jumper).

Digital Inputs and Digital Outputs: 8 inputs, TTL level compatible; 8 outputs, internally selectable TTL

level compatible or open collector with 100 mA @ 50 V drive capability.

Service Request/External Trigger Input: 1 line, TTL level compatible. Connectors: Standard: One 20-pin card edge connector. CE: One DB25 (25-pin) connector.

2 DAC488 Overview DAC488 User’s Manual

Analog Output

Terminal Installation Category: Standard: Not Applicable. CE: Category 1. DC Output Voltage and Resolution

DC Output Current and Output Resistance: 10 mA maximum; and <500 mΩ (typical) Accuracy (25 ±±±± 5°°°°C; Iout = 1 mA):

Warm Up Time to Rated Accuracy: 1 hour Temperature Coefficient (0°°°° to 20°°°° C, and 30°°°°to 50°°°° C): ±(0.002% of setting + 100 µV) / °C Channel to Channel Isolation: Standard: 500 V max, 100,000 V-Hz.

Channel to Digital Low Isolation: Standard: 500 V max, 100,000 V-Hz.

Connectors: One 12-pin quick disconnect analog.

WARNING

WARNINGWARNING

There may be up to 200 V isolation potential between analog common and earth (CE version) or up to 500 V isolation potential (Standard version). Avoid contact with analog output terminals and the cables connected to them. Do not apply power until after the AC line and analog output connections have been properly made. The AC line must remain connected to the unit whenever the analog output terminals are connected to a device exceeding 60 VDC or 30 Vrms common mode voltage. Contact with voltage potentia ls could cause bodily injury or death!

CAUTION

CAUTIONCAUTION

Solid wire is recommended for the analog output terminal connections. If stranded wire is used, then strip the wire 6 mm, and twist or tin the stripped end. After tightening the connector, check that no loose wire strands are present.

1V Range: ± 1.02375 V, 250 µV/bit 5V Range: ± 5.11875 V, 1.25 mV/bit 10V Range: ± 10.2375 V, 2.5 mV/bit.

1V Range: ±(0.05% of setting + 1 mV) 5V Range: ±(0.05% of setting + 3 mV) 10V Range: ±(0.05% of setting + 10 mV)

CE: 200 volts max, 100,000 V-Hz

CE: (Channel Common to Earth) 200 V max, 100,000 V-Hz

IEEE 488

CAUTION

CAUTIONCAUTION

The IEEE 488 terminal must only be used to control a non-isolated IEEE 488 system. The common mode voltage (cable shell to earth) must be zero.

Terminal Installation Category: Standard: Not Applicable. CE: Category 1. Implementation: SH1, AH1, T4, TE0, L4, LE0, SR1, RL0, PP0, DC1, DT1,E1. Terminators: Programmable CR, LF, LF CR and CR LF with EOI. Programmable: IEEE Bus Terminators, EOI Control, SRQ Mask, Port Voltage, Gain, Offset, Digital I/O

lines, Output Format, Internal Buffer, Mode.

Connector: Standard IEEE 488 connector with metric studs.

DAC488 User’s Manual DAC488 Overview 3

General

WARNING

WARNINGWARNING

Service: This product contains no operator serviceable parts. Fuse replacement and the changing of selected line voltage must be performed by qualified service personnel. Never open the DAC488 case while it is connected to the AC line, or when analog output terminals are connected to a device exceeding 60 VDC or 30 Vrms common mode voltage!

Terminal Installation Category: Standard: Not Applicable. CE: Category 2 for Line Voltage Input

terminal. All other terminals are Category 1.

Dimensions: 425 mm wide x 45 mm high x 309 mm deep (16.75" x 1.75" x 12") Weight: 3.32 kg. (7.31 lbs) Environment: Standard: Indoor use, 0° to 50°C; 0 to 95% RH (non-condensing).

CE: Indoor use at altitudes below 2000 meters, 0° to 40°C; 0 to 80% RH up to 31°C decreasing linearly 4% RH/°C to 40°C.

Controls: Power Switch (external), line voltage selection switch (internal), mode and IEEE address DIP

switch (external), calibration enable switch (external), digital output port configuration jumper (internal)

Indicators: LEDs for TALK, LISTEN, SRQ, ERROR, TEST and POWER Power: Internally selectable 105-125 V or 210-250 V; 50-60 Hz, 35 VA Max Fuse: 3/8A, Slo Blo, 3AG (for 105-125 V power line) or 3/4A, Slo Blo, 3AG (for 210-250 V power line)

CAUTION

CAUTIONCAUTION

Line Voltage: The protective conductor terminal on the AC line connector must be connected to an external protective earthing system. Failure to make such a connection will impair protection from shock. If common mode voltages connected to the analog input terminals exceed 60 VDC or 30 Vrms, the AC line connector must remain connected even when the unit is powered “off.” If it becomes necessary to disconnect the AC line connector, you must first disconnect all power to the analog input terminals.

CAUTION

CAUTIONCAUTION

Fuse Failure: Fuse failure indicates a possible problem within the device circuitry. If a fuse blows, contact a qualified service representative. Replacement fuses are to be installed by qualified service personnel with the unit disconnected from the power source and with all other terminals disconnected. If the line voltage selector is changed, then the fuse designated for that line voltage must be used.

4 DAC488 Overview DAC488 User’s Manual

DAC488 Setup 2

The Package…… 5 Hardware Setup…… 6

Front & Rear Panel Layouts…… 6 Default Settings…… 7 IEEE 488 Bus Address Selection…… 7 Mode Selection…… 7 Analog Output Ports…… 7 Digital I/O Port…… 8

Transistor-Transistor Logic (TTL) Lev el s…… 9 High Voltage/High Current Digital Outputs…… 9 External Trigger/SRQ Input…… 11 To Configure the Digital Output Lines…… 11

The Package

All DAC488 components are carefully inspected prior to shipment. When you receive your digital-toanalog converter system, carefully unpack all items from the shipping carton and check for any damage which may have occurred during shipment. Promptly report the damage to the shipping agent and your sales representative. Retain all shipping materials in case you must return the unit to the factory.

Every DAC488 package includes the following items listed by part number:

• DAC488/2 or DAC488/4: Digital-to-Analog Converter with Digital I/O and IEEE 488

• WINDOWS PANELS: Programmed Disks in IBM format, including Installation Card and Licensing

Agreement (PR-10)

• 107-0901: DAC488 User’s Manual

• PR-2: Warranty Card

• DAC488-003: Accessories Kit for DAC488, which includes the following:

• CA-1: Power Cable

• CA-35-2 or CA-35-6: DB25 Male-to-Female Connector, 2 or 6 feet respectively (CE version)

• CN-6-20: 20-pin Card Ed ge Connector (S tandard version)

• CN-40-12: 12-pin Analog Output Connector

• FE-1: Rubber Feet (4)

• EN-6: Rack Ears (2)

• HA-41-6: Rack Screws (4)

• PR-9: Rack Mounting Instruct i ons

• FU-1-.375: 3/8A Replacement Fuse

• FU-1-.75: 3/4A Replacement Fuse

DAC488 User’s Manual DAC488 Setup 5

Hardware Setup

Front & Rear Panel Layouts

Six LED indicators on the DAC488 front panel, display the unit status. The following list describes the functions of these indicators:

• TALK: ON when DAC488 is in the Talker state; OFF when in the Idle or Listener state.

• LISTEN: ON when DAC488 is in the Listener state; OFF when in the Idle or Talker state.

• SRQ: ON when DAC488 generated a service request; OFF when no SRQ is pending.

• ERROR: ON when an error has occurred; OFF when no error condition exists.

• TEST: ON when used in conjunction with the Test (

been established with the DAC488. The TEST LED will flash when the DAC488 is calibrating in the auto-calibration mode. The TEST LED will then remain lit when finished calibrating in the autocalibration mode.

• POWER: ON when power is being applied while the power switch is in the ON position; OFF when

power is not present.

W) command to veri fy tha t communication has

6 DAC488 Setup DAC488 User’s Manual

Default Settings

The DAC488 unit may be operated from either 110 VAC or 220 VAC. The operating voltage is set by an internal switch. The factory set operating voltage appears on the label placed over the power jack on the rear panel . To change the operating vol t age, see section Line Voltage Selection in Chapter 3.

The DAC488 unit has one 8-microswitch DIP switch (SW1) accessible from the rear panel. This DIP switch determines the IEEE 488 bus address and its operating mode. The switch is read only when the unit is powered on and should be set prior to applying power. The figure illustrates the factory default for the DIP microswitch settings. To modify the default settings, disconnect the power cord from the AC line and change the micros witch se ttings using a small screwdriver. The enclosure does not need to be opened to change the DIP microswitch settings.

IEEE 488 Bus Address Selection

The IEEE 488 bus address is set by positioning the rear-panel DIP microswitches 1 through 5. T he address can be set from 0 through 30 and is read only at power on. The address is selected by simple binary weighting with microswitch 1 being the Least Significant Bit (LSB) and microswitch 5 the Most Significant Bit (MSB). The factory default setting is address 9, as shown in the diagram. If address 31 is selected, it defaults to address 30 because the IEEE 488 standard has reserved address 31.

Mode Selection

The DAC488 can be operated in one of two modes:

Normal operating mode or automatic calibration mode, which are selected by the rear-panel DIP

microswitch 8. The factory default setting for microswitch 8 is normal operating mode, as shown in the diagram.

Analog Output Ports

The DAC488 can be considered as multiple isolated IEEE 488 to Analog Converters. The unit occupies one IEEE 488 bus address. Each port has a low (L), high (H) , and ground (case ground) l ine. The case ground line may be connected to the shield of shielded cable if this type of cable is used to carry the analog signals. The pinouts for all analog ports are labeled on the rear panel of the unit. Each analog output is capable of sourcing and sinking a maximum current of 1 0 mA.

DAC488 User’s Manual DAC488 Setup 7

Digital I/O Port

The DAC488 has eight digital input lines and eight digital output lines. At power on, the configuration of digital output lines is determined by the options saved as the startup configuration. In order to set the digital output lines to a particular state upon power on, the System Defaults ( command must be used after all the lines have been configured. For example, if it is desired to have digital output line 1 set high and the other lines set low at power on, the lines would be set to this configuration using the Digital Output ( configuration would be saved using the System Defaults (

)

D) command. Then this

) co mmand.

Digital I/O Port Pinouts

Connector Pin Connector Pin

Standard

(20-pin)

1 23 Digital Input Bit 1 (LSB ) 17 15 Flyback 2 10 Digital Input Bit 2 18 2 Ext. Trigger/SRQ Input 3 22 Digital Input Bit 3 19 14

4 9 Digital Input Bit 4 1 Digital Ground 5 21 Digital Input Bit 5 11 Digital Ground 6 8 Digital Input Bit 6 12 Digital Ground 7 20 Digital Input Bit 7 13 Digital Ground 8 7 Digital Input Bit 8 (MSB) 24 Digital Ground

9 19 Digital Output Bit 1 (LSB ) 10 6 Digital Output Bit 2 11 18 Digital Output Bit 3 12 5 Digital Output Bit 4 13 17 Digital Output Bit 5 14 4 Digital Output Bit 6 15 16 Digital Output Bit 7 16 3 Digital Output Bit 8 (MSB)

CE Version

(DB25)

Connector Pin

Description

Standard

(20-pin)

CE Version

(DB25)

+5 V (≤ 50 mA load)

25 Digital Ground

Connector Pin

Description

8 DAC488 Setup DAC488 User’s Manual

Transistor-Transistor Logic (TTL) Levels

The digital output lines will drive 2 TTL loads. All digital input lines are less than 1.5 TTL loads. All inputs are protected against damage due to high static voltages. Normal precautions should be taken to limit the input voltages to the range of -0.3 to +7.0 volts. All I/O lines are referenced to Digital Ground (Standard Version Pin 2 0, CE Version Pin 1).

High Voltage/High Current Digital Outputs

In addition to interfacing with TTL logic levels, the digital output lines can be configured as high voltage/high current outputs. These outputs can sink up to 100 mA at 50 VDC through the use of open collector drivers with integral diodes for inductive load transient suppression. This allows for interfacing the digital outputs with relays, lamps and solenoids.

As shown in the following schematics, the gates driving the digital outputs (when configured for high voltage/high current operation) contain internal diodes to suppress inductive transients. The cathodes of these diodes are tied together and connected to the Flyback pin on the digital I/O port. By connecting the Flyback pin to the positive end of the supply driving the relays, the internal diodes will be connected in parallel with the relay coils and thus prevent inductive spikes from damaging the internal circuitry of the DAC488.

DAC488 User’s Manual DAC488 Setup 9

When used with relays or solenoids, the Flyback pin on the edge card connector should be connected to the positive supply lead of the power supply used with the external devices being driven, as shown in the following figures . To configure the digital output lines for this purpose, it is necessary to open the enclosure and reposition the configuration jumper. For instructions on how this is done, see section To Configure the Digital Output Lines in the following text.

Once the digital output lines have been configured for high level operation, they can be used to drive devices such as relays, solenoids and displays. For example, a typical application may require a lamp and a relay to be driven by the Standard version DAC488. For this example, the relay is connected to digital output pin 11 and the lamp is connected to digital output pin 15, as shown in the following diagram.

Using this same example for the CE version DAC488, the relay is connected to digital output pin 18 and the lamp is connected to digital output pin 16, also shown in the next diagram.

Since a relay is used for this application, the Flyback terminal is connected to the positive terminal of the external power supply. Note also that the Ground lead of the power supply should be connected to pin 20 (Digital Ground) on the Standard card edge connector, or to pin 1 (Digital Ground) on the CE pin connector.

10 DAC488 Setup DAC488 User’s Manual

External Trigger/SRQ Input

The External Trigger/SRQ input (Standard pin 18; CE pin 2) can be used to trigger the DAC488 once it has been properly armed. The DAC488 can be programmed to trigger on a positive-going or negative-going edge by using the External Trigger Mask ( pulse. A trigger pulse may also be used to generate an SRQ by using the Service Request Mask ( command. The maximum rate at which the DAC488 can be triggered is 1 trigger pulse every 1 millisecond.

To Configure the Digital Output Lines

Do not connect external high level devices to the digital output lines unless they have first been configured for this purpose. Otherwise the interface may be damaged.

1. First, disconnect any cables from the

analog output terminals. Next, disconnect the power cord from the AC line and from the interface. Then disconnect any other cables prior to disassembly.

Q) command. Any TTL leve l signal may be used as a trigger

WARNING

WARNINGWARNING

CAUTION

CAUTIONCAUTION

2. Place the interface on a flat surface. Remove the six screws on top of the case and remove the top cover.

3. Located in front of the rear-panel DIP switch (SW1) are three sockets and a configuration jumper. This jumper is factory set to configure the digital output lines for low level TTL logic levels, as shown in the figure.

4. To configure the digital output lines as high voltage/high c urrent outputs, first remove the configuration jumper.

5. Next, reinsert it so that the center socket is now connected to the right socket, as shown in the second figure.

6. Once the jumper has been repositioned for your particular application, make note of the new setting for later reference.

7. Carefully reassemble the unit.

DAC488 User’s Manual DAC488 Setup 11

−

Notes

12 DAC488 Setup DAC488 User’s Manual

DAC488 Power & Assembly 3

Introduction…… 13

Internal Components…… 13 Factory Service…… 13

Power Line & Fuse Configuration…… 14

Line Voltage Selection…… 14

To Select the Line Voltage…… 15

Fuse Replacement…… 16

To Replace the Fuse…… 16

Rack-Mount & Bench-Top Assembly…… 17

Rack Mount…… 17 Bench Top…… 17

Power-Up & Performance Tests…… 18

Power-Up Activation…… 18 Programming Examples……19

KYBDCTRL.BAS Program…… 19 To Run the Keyboard Controller Program…… 19 DAC488 Command Responses…… 20

Performance Verification…… 20

To Verify the Port Voltage - 10-Volt Range…… 21 To Verify the Port Voltage - 5-Volt Range…… 21 To Verify the Port Voltage - 1-Volt Range…… 22 Data Transfer Speeds…… 22

Introduction

Internal Components

The heart of the DAC488 is a 6809 microprocessor [U101] supported by 16K bytes of firmware EPROM [U102] and 32K bytes of battery-backed-up RAM [U103]. Interface to the IEEE 488 bus is accomplished by a 9914 interface chip [U105]. A 65C22 [U109] generates real-time interrupts for the firmware operating system and also drives the front panel LED indicators.

Isolation of the analog ports is accomplished using separate bipolar power supplies for each port. OptoIsolators are used to isolate the digital and analog circuitry. High voltage/high current output capability is available on the digital o ut put port thr ough a 74HCTLS240 and a ULN2803A peripheral driver [U144].

Calibration of the analog ports through p rogram control is accomplished by the use of two 8-bit D/A converters on each analog circuit. One converter is used to adjust the gain and the other converter to adjust the offset.

Factory Service

Chapter 8 provides a troubleshooting reference for possible solutions to technical problems. Before calling for technical assistance, refer to this chapter.

However, if problems in using the DAC488 still persist, you should contact the factory. Many problems can be resolved by discussing the problems with the appropriate applications department. If the problem cannot be solved by this method, you will be instructed as to the proper return procedure.

DAC488 User’s Manual DAC488 Power & Assembly 13

Power Line & Fuse Configuration

The power configuration of the DAC488 unit consists of selecting the line voltage and replacing the fuses. Each DAC488 unit has a factory default to operate at 105-125 volts AC. However, each unit may be operated at either 105-125 or 210-250 VAC.

Do not use the DAC488 unit outdoors! The unit is intended for indoor use only!

Outdoor conditions could result in equipment failure, bodily injury or death!

Never disassemble the DAC488 case while it is connected to the AC power line, or

when analog output terminals are connected to a device exceeding 60 VDC or 30 Vrms common mode voltage! Internal voltage potentials exist which could cause bodily injury or death!

To change the operating voltage of the DAC488 unit, it is necessary to open the enclosure. However, before modifying the voltage, disconnect any input or output connections from the rear panel of the affected unit and then disconnect the power cord from the power line terminal.

Line voltage must be set for 105-125 or 210-250 VAC to match the power being supplied to the DAC488 unit. If the line voltage is changed, the fuse must also be changed. Refer to the following text for the line voltage switch and fuse locations.

WARNING

WARNINGWARNING

WARNING

WARNINGWARNING

Line Voltage Selection

As already mentioned, the DAC488 may be operated with 105-125 or 210-250 VAC, 50-60 Hz power, as set by its internal line-voltage switch (labelled S104). Each unit is shipped from the factory with this operating voltage setting marked on its rear panel. If this is not the appropriate power setting to be supplied to the unit, then the line voltage and power fuse must be changed to avoid damage to the unit. The linevoltage selection procedure is outlined in the following steps.

CAUTION

CAUTIONCAUTION

Service: This product contains no operator serviceable parts, or operator replaceable parts within the case. Fuse replacement and the changing of selected line voltage must be performed by qualified service personnel. Never open the DAC488 case while it is connected to the AC line, or when analog output terminals are connected to a device exceeding 60 VDC or 30 Vrms common mode voltage. Contact with voltage potentials could cause bodily injury or death!

14 DAC488 Power & Assembly DAC488 User’s Manual

Note: If disassembly or disconnections are necessary, first turn off the power, then disconnect the analog

output cables, next disconnect the AC power line, and then any other cables, prior to disassembly.

To Select the Line Voltage

1. Turn off the power, then disconnect the analog output cables. Next, disconnect the AC power line cord, and then all other test cables from the unit.

2. Place the unit on a flat surface. Remove the six screws on top of the case and remove the top cover.

3. Located next to the main power supply transformer is the line voltage selection switch (labelled S104). Using a small screwdriver, insert the tip of the screwdriver into the slot of the switch and slide the switch to the left or right until it "clicks" into place with the desired line voltage selection visible.

CAUTION

CAUTIONCAUTION

It is possible to place the line voltage switch (S104) in a partial position which could

cause equipment damage or malfunction. When changing the position of the line voltage selection switch (S104), make sure the switch is completely positioned to the 115 V or 220 V selection. The switch will “click” into place when properly positioned.

4. Install a power line fuse appropriate for the line voltage. See section Fuse Replacement – Step 3, following this section.

CAUTION

CAUTIONCAUTION

5. Make note of the new voltage setting for later reference.

6. Carefully reassemble the unit.

Note: For re-assembly, first reconnect the AC power line, next reconnect the analog output terminals, and

then any other cables, prior to reapplying power to the entire system.

DAC488 User’s Manual DAC488 Power & Assembly 15

Fuse Replacement

The DAC488 unit contains an internal AC line fuse. The fuse is located next to the internal line-voltage switch (S104). You may replace the fuse by using the procedures found in the following text.

Note: If disassembly or disconnections are necessary, first turn off the power, then disconnect the analog

To Replace the Fuse

1. Turn off the power, then disconnect the analog output cables. Next, disconnect the AC power line

cord, and then all other cables from the unit.

2. Place the unit on a flat surface. Remove the six screws on top of the case and remove the top cover.

3. Located next to the line-voltage selection switch (labelled S104) is the power fuse. Gently pull upward on the plastic fuse housing. The entire housing with the fuse inside should be removed.

4. Open the fuse housing by pushing up on the tab on the bottom of the housing. Remove the fuse, and replace it with the proper type using the following list as a guide:

CAUTION

CAUTIONCAUTION

output cables, next disconnect the AC power line, and then any other cables, prior to disassembly.

• For line voltage 105-125 V, use fuse type 3/4 A, Slo Blo, 3AG

• For line voltage 210-250 V, use fuse type 3/8 A, Slo Blo, 3AG

CAUTION

CAUTIONCAUTION

5. Close the housing. Insert the fuse into the fuse holder.

6. Make note of the new fuse rating for lat er reference. If you have also changed the operating linevoltage selection, return to the previous section Line Voltage Selection – Step 5.

7. Carefully reassemble the unit.

Note: For re-assembly, first reconnect the AC power line, next reconnect the analog output terminals, and

then any other cables, prior to reapplying power to the entire system.

16 DAC488 Power & Assembly DAC488 User’s Manual

Rack-Mount & Bench-Top Assembly

The DAC488 includes accessories for rack-mount or bench-top assembly.

Rack Mount

If rack-mount assembly is required, remove the two plastic screws from the pre-drilled holes on each side of the unit. Since the unit can be mounted with the front or rear panel facing the front of the rack fixture, remove only those screws from the set of holes that will be toward the front of the rack. Attach the two rack ears using the enclosed screws.

Bench Top

If bench-top assembly is required, install the self-adhesive rubber feet on the bottom of the unit approximately one inch from each corner.

DAC488 User’s Manual DAC488 Power & Assembly 17

Power-Up & Performance Tests

Power-Up Activation

Condition Normal (No Errors)

ROM Error RAM Error NV-RAM Checksum Error No Power

With the power c ord plugged i n and connected to the DAC488, turn on the unit by depressing the rear-panel power switch. All of the front-panel LED indicators should light up for approximately one second while the DAC488 performs an internal ROM and RAM self-check. At the end of this self-check all of the LED indicators should turn off except for POWER.

Otherwise, the DAC488 may be in an error condition according to the one of the four following LED patterns:

TALK LISTEN SRQ ERROR TEST POWER

(Off) (Off) (Off) (Off) (Off) ON

ON ON ON ON ON ON

FLASHINGFLASHINGFLASHINGFLASHINGFLASHING ON

(Off) (Off) (Off) ON (Off) ON (Off) (Off) (Off) (Off) (Off) (Off)

CAUTION

CAUTIONCAUTION

LED Patterns for Error Conditions

LED Indicators

• If all of the LED indicators remain on: T hen a ROM error has occurred.

• If the POWER LED indicator remains on while the rest of the LED indicators flash continuously:

Then a RAM error has occurred. Try cycling the power to the DAC488 to determine that the error is repeatable.

• If the POWER and ERROR LED indicator remain on while the rest of the LED indicators are off:

Then a checksum error on Non-Volatile RAM occurred, and the saved configurations may be lost. The checksum error condition may be cleared by doing a save of a configuration using the System Defaults (

S) command. The error condition may also be cleared by using the Query Error Status (E?)

command.

• If all of the LED indicators are off: Then there may not be any power being supplied to the DAC488. In this event, check to make sure that the AC power cable is securely connected at both ends. Otherwise, there may be a problem with the fuse. For more information, see section Power Line & Fuse Configuration earlier in this chapter.

18 DAC488 Power & Assembly DAC488 User’s Manual

Programming Examples

The DAC488 programming examples use the Personal488 PC/IEEE 488 controller interface and the BASIC Keyboard Controller (KBC) program. This KBC program listed below.

KYBDCTRL.BAS Program

10 ' Personal488 Keyboard Controller Program 20 ' 30 ' For use with the IOtech Personal488 40 ' IEEE 488 interface 50 ' 100 OPEN "\DEV\IEEEOUT" FOR OUTPUT AS #1 110 IOCTL#1,"BREAK" 120 PRINT#1,"RESET" 130 OPEN "\DEV\IEEEIN" FOR INPUT AS #2 140 ' 150 ON ERROR GOTO 300 160 PRINT#1,"ERROR OFF" 170 ' 180 LINE INPUT "CMD> ",CMD$ 190 PRINT#1,CMD$ 200 ' 210 IF IOCTL$(2)<>"1" THEN 180 220 PRINT INPUT$(1,2); 230 GOTO 210 290 ' 300 ' Error Handler 310 ' 320 IOCTL#1,"BREAK" 330 PRINT#1,"STATUS" 340 INPUT#2,ST$ 350 PRINT CHR$(7);"Error #";MID$(ST$,15,2);": ";MID$(ST$,27) 360 RESUME NEXT

KYBDCTRL.BAS is included on the disk and is

The Keyboard Controller (KBC) program allows direct communication with the DAC488 (or any IEEE 488 device on the bus) via the keyboard, and displays any responses on the screen. This program is a convenient method of exercising the DAC488 and becoming familiar with the commands and their actions.

To Run the Keyboard Controller Program

1. First, set the rear-panel DIP switch for bus address 9.

2. Connect an IEEE 488 cable from the IEEE 488 connector on the DAC488 to the IEEE 488 connector

on the Personal488 PC/IEEE 488 controller interface card.

3. Turn on the DAC488 by depressing the rear-panel power switch.

4. From the MS-DOS prompt on your computer screen, run the Keyboard Controller Program

KYBDCTRL.BAS and verify that the CMD> prompt appears on the screen.

DAC488 User’s Manual DAC488 Power & Assembly 19

DAC488 Command Responses

(1) (2) (3) (4)

(5) (6)

(7) (8)

CMD> CMD>OUTPUT 09;W1X CMD>OUTPUT 09;W0X CMD>ENTER 09

A1 C0 P1 R0 V+00.00000 CMD>OUTPUT 09;P1 C0 A0 R3 V5.678 CMD>ENTER 09

A0 C0 P1 R3 V+05.67750 CMD>OUTPUT 09;P1 C0 A0 R3 V4.321 CMD>ENTER 09

A0 C0 P2 R2 V+04.32000

The above is a listing of the commands given to the DAC488 and the response received. Some commands and command responses are separated by extra vertical and horizo ntal spaces for clarity although these spaces will not actually appear when using the program. These eight command responses are explained as follows:

• Line 1: Initial command prompt from the Keyboard Controller program.

• Line 2: Instruct the DAC488 to turn on its TEST LED indicator. The TEST LED indicator should light

up.

• Line 3: Instruct the DAC488 to turn off its TEST LED indicator. The TEST LED indicator should turn

off.

• Line 4: Retrieve the DAC488 default status: Autorange on, Direct control mode, Port 1 selected,

Ground range , and 0.0 volts.

• Line 5: Program the DAC488 Port 1 for 5.678 volts. A digital multimeter (DMM) connected to Port 1 should read 5.677 volts (± 10 mV) after this command string is executed.

• Line 6: Retrieve the DAC488 status: The programmed 5.678 volts was rounded to 5.67750 volts.

• Line 7: Program the DAC488 Port 2 for 4.321 volts. A digital multimeter (DMM) connected to Port 2 should read 4.320 volts (± 10 mV) after this command string is executed.

• Line 8: Retrieve the DAC488 status: The programmed 4.321 volts was rounded to 4.32000 volts.

Performance Verification

To verify that each DAC488 port is functioning within the specifications, the following procedure may be used. If the port voltage is measured using a Keithley 199 DMM/Scanner, the reading should fall between the low and high limits listed in the tables. The procedure is given for Port 1 although each port may be tested by the Port Select ( DMM/Scanner using the calibration cable described in Chapter 6.

) command. It is assumed that the DAC488 is connected to the Keithley 199

20 DAC488 Power & Assembly DAC488 User’s Manual

To Verify the Port Voltage – 10-Volt Range

1. Send the following command string to the DAC488:

•

= Direct Control Mode • R3 = 10-Volt Range

•

P1 = Port 1 • V10 = Output +10 Volts

•

A0 = Autorange Off • X = Execute

2. Send the following command string to the 199 DMM:

•

F0 = DC Volts • N1 = Scanner Channel 1

•

= 30-Volt Range • S1 = 5 ½ Digit Resolution

Z0 = Zero Disabled • X = Execute

•

3. For each test, the specific Value Output (

V) command, its commanded output voltage, and its

corresponding Low Limit and High Limit, are as follows:

V10 = Output +10 V +9.985 ≤ Reading ≤ +10.015 Volts

•

V5 = Output +5 V +4.990 ≤ Reading ≤ +5.010 Volts

•

V1 = Output +1 V +0.994 ≤ Reading ≤ +1.006 Volts

•

V0 = Output 0 V -0.005 ≤ Reading ≤ +0.005 Volts

•

V-1 = Output -1 V -1.006 ≤ Reading ≤ -0.994 Volts

•

V-5 = Output -5 V -5.010 ≤ Reading ≤ -4.990 Volts

•

V-10 = Output -10 V -10.015 ≤ Reading ≤ -9.985 Volts

To Verify the Port Voltage – 5-Volt Range

1. Send the following command string to the DAC488:

C0 P1 A0 R3 V10 X where:

F0 R3 Z0 N1 S1 X where:

C0 P1 A0 R2 V5 X where:

•

C0 = Direct Control Mode • R2 = 5-Volt Range

•

P1 = Port 1 • V5 = Output +5 Volts

•

A0 = Autorange Off • X = Execute

2. Send the following command string to the 199 DMM:

•

F0 = DC Volts • N1 = Scanner Channel 1

•

= 30-Volt Range • S1 = 5 ½ Digit Resolution

Z0 = Zero Disabled • X = Execute

•

3. For each test, the specific Value Output (

) command, its commanded output voltage, and its

corresponding Low Limit and High Limit, are as follows:

•

V5 = Output +5 V +4.9920 ≤ Reading ≤ +5.0080 Volts

•

V2.5 = Output +2.5 V +2.4945 ≤ Reading ≤ +2.5055 Volts

•

= Output +1 V +0.9960 ≤ Reading ≤ +1.0040 Volts

V0 = Output 0 V -0.0030 ≤ Reading ≤ +0.0030 Volts

•

V-1 = Output -1 V -0.9960 ≤ Reading ≤ -1.0040 Volts

•

V-2.5 = Output –2.5 V -2.4945 ≤ Reading ≤ -2.5055 Volts

•

V-5 = Output -5 V -4.9920 ≤ Reading ≤ -5.0080 Volts

F0 R3 Z0 N1 S1 X

where:

DAC488 User’s Manual DAC488 Power & Assembly 21

To Verify the Port Voltage – 1-Volt Range

1. Send the following command string to the DAC488:

•

= Direct Control Mode • R1 = 1-Volt Range

•

P1 = Port 1 • V1 = Output +1 Volt

•

A0 = Autorange Off • X = Execute

2. Send the following command string to the 199 DMM:

•

F0 = DC Volts • N1 = Scanner Channel 1

•

= 3-Volt Range • S1 = 5 ½ Digit Resolution

Z0 = Zero Disabled • X = Execute

•

3. For each test, the specific Value Output (

V) command, its commanded output voltage, and its

C0 P1 A0 R1 V1 X where:

F0 R2 Z0 N1 S1 X where:

corresponding Low Limit and High Limit, are as follows:

V1 = Output +1 V +0.9980 ≤ Reading ≤ +1.0020 Volts

•

V0.5 = Output +0.5 V +0.4985 ≤ Reading ≤ +0.5015 Volts

•

V0.1 = Output +0.1 V +0.0989 ≤ Reading ≤ +0.1011 Volts

•

V0 = Output 0 V -0.0010 ≤ Reading ≤ +0.0010 Volts

•

V-0.1 = Output –0.1 V -0.1011 ≤ Reading ≤ -0.0989 Volts

•

V-0.5 = Output –0.5 V -0.5015 ≤ Reading ≤ -0.4985 Volts

•

V-1 = Output -1 V -1.0020 ≤ Reading ≤ -0.9980 Volts

Data Transfer Speeds

The DAC488 has been measured to perform at the approximate speeds listed below. All explanations discuss only one port, although the information given is val id for any port. These values are relative to the controller used. The speeds you encounter may vary.

• Output of Data to the Analog Ports: When sending data to the analog outputs on a port of the DAC488, the outputs may be changed about once every 4 milliseconds when specifying voltages in bits, or once every 25 milliseconds when specifying voltages in volts.

• Output of Data to the Digital Output Port: Data may be sent to the digital output port at an approximate rate of once every 2.5 milliseconds.

• Input of Data from the Digital Inp ut Port: The digital input port may be read at an approximate rate of once every 75 milliseconds.

22 DAC488 Power & Assembly DAC488 User’s Manual

DAC488 Operation 4

Introduction…… 23 Command Groups…… 23

Port Triggering…… 24

Internal Buffer…… 26

Control Modes…… 28

Introduction

The DAC488 provides multiple independently programmable 12-bit plus-sign Digital-to-Analog Converters (DACs). Three voltage ranges, ±1, ±5, and ±10, are available on a per port basis as well as an autorange feature which automatically selects the range giving the best resolution for the specified voltage. The DAC ports may be programmed in terms volts or bits. The resolution per bit on each range is: 250 µV/bit (±1 V range), 1.25 mV/bit (±5 V range), and 2.5 mV/bit (±10 V range). Volts are programmed with decimal floating poi nt numbers in the range of ±10.2375 or ±1.2375E+1. Voltages may also be programmed in decimal bits (range = ±4095) or 16-bit hexadecimal two's complement numbers (range = F001 to 0FFF).

System & Port Commands…… 23 Command Support…… 24

Trigger Processing & Trigger Overrun…… 25

Buffer Data…… 26 Buffer Save-and-Restore Program…… 27

Direct Control Mode…… 28 Indirect Control Mode……28 Stepped Control Mode…… 28 Waveform Control Mode…… 29

Multiple Port Synchronization…… 30

Synchronized Waveforms Program…… 30

Digital I/O Port…… 32 User-Defined System Defaults…… 33 IEEE 488 Bus Support…… 33

Bus Lines…… 33 Bus Commands…… 34 Bus Addresses…… 34 Bus Terminators…… 34

Command Groups

Operation of the DAC488 is accomplished using a set of commands that configure the entire interface as well as each DAC port. The DAC488 commands can be divided into two main groups: System commands and port commands.

System & Port Commands

System commands affect the operation of the entire interface and are not specific to a given port. Meanwhile, port commands only affect the operation of the selected port. The port is selected using the Port Select (

Syntax Name Syntax Name

@ D E? G K M O P Q S T U W X Y

) command. The 15 system commands and the 11 port commands are listed below:

Command Trigger Digital Output Query Error Status GET Trigger Mask End-Or-Identify Control Service Request Mask Output Format Port Select External Trigger Mask System Defaults Command Trigger Mask User Status Test Execute Bus Terminator

System Commands Port Commands

A B C F H I J L N R V

Autorange Buffer Data Control Mode Buffer Definition Offset Calibration Interval Gain Calibration Buffer Location Number of Cycles Range Select Value Output

DAC488 User’s Manual DAC488 Operation 23

Command Support

Support for the above commands, includes the Query (?) command extension, and the use of the Serial Poll Status Byte. Refer to Chapter 7 for more details.

Port Triggering

Triggering is t he process of changing a DAC output at the occurrence of a trigger event. The three trigger events which can trigger a DAC port are: a Trigger On ( IEEE Group Execute Trigger ( external trigger pulse applied to the external trigger/SRQ input. Any DAC port may be configured to trigger on one or more of the s e trigger sources. These trigger sources and their relationship to a DAC port are shown in the following diagram.

As shown in the diagram, the trigger sources are routed to the ports by using the trigger mask c ommands. The trigge r mask commands are illustrated as switches. The trigger mask commands are used to enable a trigger source to trigger the selected DAC port. All trigger signals are then combined to allow a port to be triggered upon the occurrence of any of the three trigger events.

@) command, an

GET) or an

Triggering is provided as a means of synchronizing multiple DAC ports. Voltages may be output at two or more ports simultaneously by programming each port for the desired voltages and trigger event(s). When the trigger event occurs, the programmed voltages will appear at the ports simultaneously.

24 DAC488 Operation DAC488 User’s Manual

+ 84 hidden pages

Measurement DAC488 v.1 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Warranty

Warnings and Cautions

Introduction to this Manual

Table of Contents

Introduction

Accessories

Specifications

Digital I/O

Analog Output

CAUTION

IEEE 488

General

WARNING

CAUTION

CAUTION

The Package

Hardware Setup

Front & Rear Panel Layouts

Default Settings

IEEE 488 Bus Address Selection

Mode Selection

Analog Output Ports

Digital I/O Port

Transistor-Transistor Logic (TTL) Levels

High Voltage/High Current Digital Outputs

External Trigger/SRQ Input

To Configure the Digital Output Lines

WARNING

Introduction

Internal Components

Factory Service

Power Line & Fuse Configuration

WARNING

WARNING

Line Voltage Selection

To Select the Line Voltage

Fuse Replacement

To Replace the Fuse

Rack-Mount & Bench-Top Assembly

Rack Mount

Bench Top

Power-Up & Performance Tests

Power-Up Activation

CAUTION

Programming Examples

KYBDCTRL.BAS Program

To Run the Keyboard Controller Program

DAC488 Command Responses

Performance Verification

To Verify the Port Voltage – 10-Volt Range

To Verify the Port Voltage – 5-Volt Range

To Verify the Port Voltage – 1-Volt Range

Data Transfer Speeds

Introduction

Command Groups

System & Port Commands

Command Support

Port Triggering