Measurement Extender488 User Manual

Measurement Computing

Extender 488 User’s Manual

1996-1997 by Measurement Computing Corp.

Printed in the United States of America

the smart approach to instrumentation ™

10 Commerce Way

Norton, MA 02766

Fax: [phone]

[phone]

[e-mail]

www.mccdaq.com

p/n Extender488-901

Part No. Extender488-901

Warranty Information

Contact Measurement Computing by phone, fax, or e-mail in regard to warranty-related issues:
Phone: [phone], fax: [phone], e-mail: [e-mail]

Many Measurement Computing products carry the CE marker indicating they comply with the safety and emissions
standards of the European Community. When applicable these products have a Declaration of Conformity stating which
specifications and operating conditions apply. You can view the Declarations of Conformity at

www.mccdaq.com/legal.aspx (CE Information page).

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.

This symbol indicates the message is important, but is not of a Warning or Caution category. These notes can be of great
benefit to the user, and should be read.

In this manual, the book symbol always precedes the words “Reference Note.” This type of note identifies the location
of additional information that may prove helpful. References may be made to other chapters or other documentation.

Tips provide advice that may save time during a procedure, or help to clarify an issue. Tips may include additional
reference.

Limitation of Liability

Measurement Computing cannot be held liable for any damages resulting from the use or misuse of this product.

Copyright, Trademark, and Licensing Notice

All Measurement Computing 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 Measurement Computing’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.

CE Notice

Warnings, Cautions, Notes, and Tips

Specifications and Calibration

Specifications are subject to change without notice. Significant changes will be addressed in an addendum or revision to
the manual. As applicable, the hardware is calibrated 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.

Table of Contents

Section 1 INTRODUCTION Page

1.1 Description 1.1

1.2 Available Accessories 1.2

1.3 Extender488 Specifications 1.3

1.4 Extender488/F Specifications 1.4

1.5 Abbreviations 1.5

Section 2 GETTING STARTED Page

2.1 Inspection 2.1

2.2 Extender488 Configuration 2.2

2.2.1 Extender488 Serial Baud Rate Selection 2.2

2.2.2 Extender488 Serial Data Format Selection 2.3

2.2.3 Extender488 Serial Port Cabling 2.4

2.3 Extender488/F Configuration 2.5

2.3.1 Extender488 Fiber Optic Connections 2.5

2.4 Operation 2.7

2.5 Parallel Poll Response Times 2.9

Section 3 IEEE 488 Primer Page

3.1 History 3.1

3.2 General Structure 3.1

3.3 Send It To My Address 3.4

3.4 Bus Management Lines 3.4

3.4.1 Attention (ATN) 3.4

3.4.2 Interface Clear (IFC) 3.5

3.4.3 Remote Enable (REN) 3.5

3.4.4 End Or Identify (EOI) 3.5

3.4.5 Service Request (SRQ) 3.5

3.5 Handshake Lines 3.6

3.5.1 Data Valid (DAV) 3.6

3.5.2 Not Ready For Data (NRFD) 3.6

3.5.3 Not Data Accepted (NDAC) 3.6

3.6 Data Lines 3.7

3.7 Multiline Commands 3.7

3.7.1 Go To Local (GTL) 3.7

3.7.2 Listen Address Group (LAG) 3.8

Table of Contents

Section 3 IEEE 488 Primer Page

3.7.3 Unlisten (UNL) 3.8

3.7.4 Talk Address Group (TAG) 3.8

3.7.5 Untalk (UNT) 3.8

3.7.6 Local Lockout (LLO) 3.8

3.7.7 Device Clear (DCL) 3.8

3.7.8 Selected Device Clear (SDC) 3.9

3.7.9 Serial Poll Disable (SPD) 3.9

3.7.10 Serial Poll Enable (SPE) 3.9

3.7.11 Group Execute Trigger (GET) 3.9

3.7.12 Take Control (TCT) 3.9

3.7.13 Secondary Command Group (SCG) 3.9

3.7.14 Parallel Poll Configure (PPC) 3.10

3.7.15 Parallel Poll Unconfigure (PPU) 3.10

3.8 More On Service Requests 3.10

3.8.1 Serial Poll 3.11

3.8.2 Parallel Poll 3.11

Section 4 SERVICE INFORMATION Page

4.1 Factory Service 4.1

4.2 Theory of Operation 4.1

4.3 Extender488 Component Layout 4.2

4.4 Extender488/F Fiber Optic I/O Layout 4.3

4.4 Replaceable Parts List 4.4

Appendix A IEEE Command and Address Messages

Section 1 Introduction

INTRODUCTION

1.1 DESCRIPTION

The Extender488s enable IEEE 488 devices to be co ntrolled up to 4,000 feet from the h ost
computer. This overcomes the limit imposed by the IEEE 488 specification of 6 feet between any two
devices, to a m aximum of 60 feet total chained length. I n addition, the Extender488s allows up to 30
devices to be on the bus, versus the 15 device limit imposed by the IEEE standard.

Two extenders are required to perform bus extension. The bus connecting the host computer, or
controller, is the "local" bus. T he bus to which control is extended is the "remote" bus. One of the
Extender488s is required on each bus to accomplish IEEE bus extension.

Communication between extenders is accomplished with serial data transmission, using RS-422 data
drivers and receivers with the Extender488. This differential serial data format provides high noise
immunity and long-distance capability using low cost twisted pair wire.

The Extender488/F communicates serially over duplex fiber optic cables. Fiber optic transmission
provides high noise immunity, low RFI emissions and long-distance capability.

Operation of the Extender488s is completely transparent to the system. The controller can acces s
both local and remote devices in exactly the same manner, with the exception of Parallel Poll.

1-1

Section 1 Introduction

1.2 AVAILABLE ACCESSORIES

The following accessories are available from Measurement Computing for use with the

CA-7-1
CA-7-2
CA-7-3
CA-7-2
CA-18-X

connectors for the Extender488;

CA-24-X

Extender488/F;

CN-20
CN-21
CN-22

CN-23
114-0920
Rack488-1
Rack488-2
TR-2

TR-2E

1.5 f
6 foot IEEE 488 cable
6 foot IEEE 488 cable; shielded
6 foot IEEE 488 cable; reverse entry

Shielded serial cable with mating

Right angle IEEE 488 adapter
IEEE 488 connector extender
IEEE 488 multi-tap bus strip;

Additional Manual

oot IEEE 488 cable

specify X in feet from 100 to 4000
100µm/140µm duplex fiber optic cable
with mating connectors for the

specify X in feet from 100 to 4000

4 connectors in parallel
IEEE 488 panel mount feed-thru connector

Rack mount kit; one Extender488 package
Rack mount kit; two Extender488 packages
External power supply for Extender488
105-125v; 50/60 Hz
External power supply for Extender488
210-250v; 50 Hz

Exten

der488

s.

Refer to the

Measurement Computing catalog for those accessories not listed here.

1-2

Section 1 Introduction

1.3 Extender488 SPECIFICATIONS

IEEE 488-1978

Implementation: Proprietary transparent control and data transfers.
Connector: Standard IEEE 488 connector with metric studs.

Serial Interface

EIA RS-422A: Balanced voltage on TxD and RxD.
Connector: 9-pin Sub-D female.
Character Set: Proprietary asynchronous bit serial.
Baud Rate: Selectable 300, 600, 1200, 2400, 4800, 9600, 19,200 and

115,200.
Data Format: Selectable 7 or 8 data bits; 1 stop bit; odd parity.
Max. Cable Length: 1000 meters.

General

Data Rates: Specifications apply to data transfers after

addressing has been established.

Baud Rate Data Rate

300 13

600 26

1200 53

2400 105

4800 204

9600 385

19.2K 691

115.2K 3400

(bytes per second, avg)

Indicators: LEDs for IEEE Talk, Listen, SRQ, Error and Power.
Power: 105-125V or 210-250V; 50-60 Hz, 10 VA Max.
Dimensions: 188mm deep x 140mm wide x 68mm high (7.39" x 5.5" x 2.68").
Weight: 1.35 kg. (3.1 lbs).
Environment: 0¡ - 50¡C; 0 to 70% R.H. to 35¡C.

Linearly derate 3% R.H./¡C from 35¡ to 50¡C.
Controls: Power Switch (external),

Serial parameter switches (internal).

Specifications subject to change without notice.

1-3

Section 1 Introduction

1.4 Extender488/F SPECIFICATIONS

IEEE 488-1978

Implementation: Proprietary transparent control and data transfers.
Connector: Standard IEEE 488 connector with metric studs.

Fiber Optic Interface

Wavelength: 820 nanometers typical.
Connectors: SMA-905 series female.
Required Cable: Duplex 100µm, 140µm clad fiber optic.

200MHz-km bandwidth; 6 db/km max. attenuation.

Max. Cable Length: 1000 meters.

General

Data Rates: 3400 bytes per second typical.
Indicators: LEDs for IEEE Talk, Listen, SRQ, Error and Power.
Power: 105-125V or 210-250V; 50-60 Hz, 10 VA Max.
Dimensions: 188mm deep x 140mm wide x 68mm high

(7.39" x 5.5" x 2.68").
Weight: 1.55 kg. (3.6 lbs).
Environment: 0¡ - 50¡C; 0 to 70% R.H. to 35¡C.

Linearly derate 3% R.H./¡C from 35¡ to 50¡C.
Controls: Power Switch (external).

Specifications subject to change without notice.

1-4

Section 1 Introduction

1.5 ABBREVIATIONS

The following IEEE 488 abbreviations are used throughout this manual.

addr n IEEE bus address "n"
ATN Attention line
CA Controller Active
CO Controller
CR Carriage Return
data Data String
DCL Device Clear
GET Group Execute Trigger
GTL Go To Local
LA Listener Active
LAG Listen Address Group
LF Line Feed
LLO Local Lock Out
MLA My Listen Address
MTA My Talk Address
PE Peripheral
PPC Parallel Poll Configure
PPU Parallel Poll Unconfigure
SC System Controller
SDC Selected Device Clear
SPD Serial Poll Disable
SPE Serial Poll Enable
SRQ Service Request
TA Talker Active
TAD Talker Address
TCT Take Control
term Terminator
UNL Unlisten
UNT Untalk
* Unasserted

1-5

Section 2 Getting Started

GETTING STARTED

2.1 INSPECTION

The Extender488s are carefully inspected, both mechanically a nd electrically, prior to shipment.
When you receive the interface, carefully unpack all items from the s hipping carton and check for any
obvious signs of physical damage w hich may have occurred during shipment. Immediately report any
damage found to the shipping agent. Remember to retain all shipping materials in the event that shipment
back to the factory becomes necessary.

Every Extender488 is shipped with the following....



Extender488 IEEE bus extender interface



TR-2 or TR-2E Power Supply; TR-4 115V

TR-4E 220V



114-0920 Instruction Manual

Note: accessories ordered may be packaged and shipped separately

WARNING
The Extender488 requires a regulated external power s upply with a maximum
output of 5.25 volts! Using voltages above this level will result in damage to the
interface. Use only power supplies provided by

2.

1

Measurement Computing.

Section 2 Getting Started

2.2 Extender488 CONFIGURATION

The following describes the configuration necessary for the RS-422

the fiber optic extenders, refer to Section 2.3.

Two

Extender488

LOCAL

(ATN) and Remote Enable (REN) lines. The Error LED on each extender will blink indicating that ATN or
REN has not yet been detected and that communication with the other extender has not yet been
established. The first extender to detect either of t hese lines asserted declares itself the
and commands the other extender to declare itself the
blinking. From this moment on, the
activity to the
back to the

IEEE bus, and the other connected to the

Both local and remote extenders are identical. At power up, each extender monitors the Attention

REMOTE

LOCAL

2.2.1 Extender488 Serial Baud Rate Selection

The
applications, this is the most efficient
extreme distances from each other, baud rates other than 115.2K can be selected. Selectable bau d
rates include 115.2K, 19.2K, 9600, 4800, 2400, 1200, 600, 300. Both extenders must be set to the
same baud rate for proper operation.

To modify the baud rate, follow this simple procedure: Disconnect the power supply from
the AC line and from the interface. Disconnect any IEEE or serial cables prior to disassembly.

s are required to accomplish bus extension, with one c onnected directly to the

REMOTE

LOCAL

extender. All activity detected by the

extender.

Extender488

is shipped with the serial baud rate set to 115.2K baud. For most

extender will monitor all local bus activity and transmit this

operating rate. However, if the extenders are to be located at

IEEE bus.

REMOTE

extender. The Error LEDs will now stop

REMOTE

Extender488

extender is also communicated

s. If you are using

LOCAL

extender

2.

2