IOtech Isolator488 User manual

[phone] | [email protected] | artisantg.com
-~
ARTISAN
®
~I
TECHNOLOGY
GROUP
Your definitive source
for
quality
pre-owned
equipment.
Artisan Technology
Group
Full-service,
independent
repair
center
with
experienced
engineers
and
technicians
on staff.
We
buy
your
excess,
underutilized,
and
idle
equipment
along
with
credit
for
buybacks
and
trade-ins
.
Custom
engineering
so
your
equipment
works
exactly as
you
specify.
•
Critical
and
expedited
services
•
Leasing
/
Rentals/
Demos
• In
stock/
Ready-to-ship
•
!TAR-certified
secure
asset
solutions
Expert
team
ITrust
guarantee
I
100%
satisfaction
All
tr
ademarks,
br
a
nd
names, a
nd
br
a
nd
s a
pp
earing here
in
are
th
e property of
th
e
ir
r
es
pecti
ve
ow
ner
s.
Visit our website - Click HERE

Isolator488 IEEE 488 Bus Isolator
USER’S MANUAL
IOtech, Inc. • 25971 Cannon Road • Cleveland, Ohio 44146 • [phone]

Warranty Information
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: [phone], fax: [phone], e-mail: [email protected]
Limitation of Liability
IOtech, Inc. cannot be held liable for any damages resulting from the use or misuse of this product.
Copyright, Trademark, and Licensing Notice
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, Cautions, Notes, and Tips
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 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.
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, IOtech calibrates its hardware 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 suggestions.

Isolator488
Instruction Manual
Part No. Isolator488-901
Revision 1.2
December 1991
IOtech, Inc.

25971 Cannon Road

Cleveland, Ohio 44146

[phone]

IMPORTANT!
READ THIS BEFORE INSTALLATION!
WARNING
The enclosure of the Isolator488 Bus Isolator is
internally connected to earth ground through the
power cord. However, the shield of the IEEE 488
cables attached to the Isolator488 and signal ground
pins may be at a high voltage with respect to earth
ground. Be sure to remove power from all devices in
your system before handling IEEE 488 cables
connected to the Isolator488. Failure to follow this
warning may result in personal injury or death.
IOtech, Inc. • 25971 Cannon Road • Cleveland, Ohio 44146 • [phone]

Table of Contents
Section 1 INTRODUCTION Page
1.1 General Description 1.1
1.2 Available Accessories 1.1
1.3 Specifications 1.2
1.4 Abbreviations 1.3
Section 2 GETTING STARTED Page
2.1 Inspection 2.1
2.2 Configuration 2.1
2.3 Modifications 2.4
2.4 Line Voltage Selection 2.7
2.5 Hardware Installations 2.9
2.6 Operation 2.10
2.6.1 BusLoading 2.11
2.6.2 Cabling Length 2.11
2.6.3 Signal Line Direction 2.12
2.6.4 Parallel Polling 2.13
2.6.5 Passing Control 2.13
Section 3 IEEE 488 Primer Page
3.1 History 3.1
3.2 General Structure 3.1
3.3 Send It To My Address 3.5
3.4 Bus Management Lines 3.5
3.4. Attention (ATN) 3.5
3.4.2 Interface Clear (IFC) 3.6
3.4.3 Remote Enable (REN) 3.6
3.4.4 End Or Identify (EOI) 3.6
3.4. Service Request (SRQ) 3.6
3.5 Handshake Lines 3.7
3.5.1 Data Valid (DAV) 3.7
3.5.2 Not Ready For Data (NRFD) 3.7
3.5.3 Not Data Accepted (NDAC) 3.7
3.6 Data Lines 3.8
3.7 Multiline Commands 3.8

Section 3 (cont.) Page
3.7.1 Go To Local (GTL) 3.8
3.7.2 Listen Address Group (LAG) 3.9
3.7.3 Unlisten (UNL) 3.9
3.7.4 Talk Address Group (TAG) 3.9
3.7.5 Untalk (UNT) 3.9
3.7.6 Local Lockout (LLO) 3.9
3.7.7 Device Clear (DCL) 3.9
3.7.8 Selected Device Clear (SDC) 3.10
3.7.9 Serial Poll Disable (SPD) 3.10
3.7.10 Serial Poll Enable (SPE) 3.10
3.7.11 Group Execute Trigger (GET) 3.10
3.7.12 Take Control (TCT) 3.10
3.7.13 Secondary Command Group (SCG) 3.10
3.7.14 Parallel Poll Configure (PPC) 3.11
3.7.15 Parallel Poll Unconfigure (PPU) 3.11
3.8 More On Service Requests 3.11
3.8.1 Serial Poll 3.12
3.8.2 Parallel Poll 3.12
Section 4 SERVICE INFORMATION Page
4.1 Factory Service 4.1
Appendix A Character Codes and IEEE Multiline Messages

Section 1 Introduction
1.1
Introduction
1.1 GENERAL DESCRIPTION
The Isolator488 increases the number of IEEE instruments and devices allowable
on the bus from 15, including the controller, to 28 while also providing optical
isolation between the system controller and devices on the isolated bus. Since the
Isolator488 does not occupy a bus address, its operation is entirely transparent to the
IEEE controller. The IEEE standard defines 31 valid primary bus addresses.
Therefore, no special software or bank switching is necessary to access the additional
devices allowed by the Isolator488. The Isolator488 and has no effect on bus data
transfer rates.
Two IEEE ports are provided. One connects directly to the controller's IEEE bus,
the other to an additional 14 instruments, printers, plotters and specialized peripherals
which may need to be optically isolated from the system controller.
1.2 AVAILABLE ACCESSORIES
Additional accessories that can be ordered for the Isolator488 include:
123-0900 Instruction Manual
CA-7-1 1.5 foot IEEE 488 cable
CA-7-2 6 foot IEEE 488 cable
CA-7-3 6 foot Shielded IEEE 488 cable
CA-7-4 Reverse entry 6 foot IEEE 488 cable
CN-20 Right Angle IEEE 488 adapter, male and female
CN-21 IEEE 488 connector Extender, male and female
CN-22 IEEE 488 multi-tap bus strip, four female
connectors wired in parallel.
CN-23 IEEE 488 panel mount feed-through connector,
male and female

Section 1 Introduction
1.2
1.3 SPECIFICATIONS
PROPAGATION DELAYS:
Local to Remote Talker
Data Lines 85 nS typ., 120 nS Max.
Command Lines 90 nS typ., 125 nS Max.
Remote to Local Talker
/ATN to Local Data 355 nS typ., 475 nS Max.
/ATN to Local DAV 155 nS typ., 2075 nS Max.
Data Lines 85 nS typ., 120 nS Max.
Command Lines 90 nS typ., 125 nS Max.
Parallel Poll Response 140 nS typ., 205 nS Max.
SIGNAL LINE DIRECTIONS:
Data Lines:
DIO1 - DIO7 Bidirectional
Handshake Lines:
DAV, NRFD, NDAC Bidirectional
Command Lines:
SRQ, ATN, REN, IFC To Local Bus
ATN To Remote Bus
EOI Bidirectional
CONNECTORS: Two IEEE 488 connectors with metric studs
INDICATORS: LED for Power
POWER: 105-125V or 210-250V,50, 60 Hz; 20 VA MAX.
ENVIRONMENT: 0 to 50 °C; 0 to 70% RH
DIMENSIONS: 425 mm deep x 45 mm wide x 208 mm high.
(16.75 "x 1.75 "x 8.20 ")
WEIGHT: 2.1 kg (4.6 lbs)
CONTROLS: Power switch
SUPPLIED ACCESSORIES: Power cable and manual
ISOLATION: IEEE 488 common on Controller Bus to IEEE 488
common on Instrument Bus:
1600 volts peak maximum @ sea level to 10,000 ft.
0 - 70° C, and 0 - 80% RH non-condensing OR
500 Vac maximum, 105V-Hz
Specifications are subject to change without notice.

Section 1 Introduction
1.3
1.4 Abbreviations
The following IEEE 488 abbreviations are used throughout this manual.
addr n IEEE bus address "n"
ATN Attention line
CA Controller Active
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
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

Section 2 Getting Started
2.1
GETTING STARTED
2.1 Inspection
The Isolator488 was carefully inspected, mechanically and electrically, prior to
shipment. When you receive the interface, carefully unpack all items from the
shipping carton and check for any obvious signs of physical damage which may have
occurred during shipment. Report any damage to the shipping agent immediately.
Remember to retain all shipping materials in the event that shipment back to the
factory becomes necessary.
Every Isolator488 is shipped with the following....
• Isolator488 IEEE Bus Isolator
• 123-0900 Instruction Manual
• 123-0800 Accessory Kit ( includes power cable,
fuse, and rack mounting hardware)
2.2 Configuration
Before using the Isolator488, you should be aware of the connections
between the IEEE digital commons, the shield lines on each bus, and earth ground.
The following information is provided so that you can determine if the factory
configuration is appropriate for your application or if some changes need to be
made prior to use.
The following is a list of terms and their definitions as used in this manual:
Isolation The ability of the Isolator488 to break the electrical
connection between the shields and digital commons
of its IEEE 488 ports while allowing the transfer of
data.

Section 2 Getting Started
2.2
Earth Ground The Ground terminal on the AC power cable. This is
internally connected to the chassis of the Isolator488.
Controller Port The IEE 488 port labeled CONTROLLER on the rear
panel of the Isolator488. The system controller
must be connected to this port. Instruments may also be
connected to this port, but instruments placed in the
CONTROLLER port will not be isolated from the
system controller.
Instrument Port The IEEE488 port labeled INSTRUMENTS on the
rear panel of the Isolator488. Instruments may be
connected to this port. Instruments connected to the
Instrument Port may be isolated from devices on the
Controller Port depending on the internal configuration
of the Isolator 488.
Controller Common The logic common connection on the Controller Port.
Pins 18, 19, 20, 21,22, 23, and 24 of the Controller
Port are all connected to Controller Common.
Instrument Common The logic common connection on the Instrument Port.
Pins 18, 19, 20, 21, 22, 23, and 24 of the Controller
Port are all connected to Instrument Common.
Controller Shield The Shield connection (Pin 12) on the Controller Port.
Instrument Shield The Shield connection (Pin 12) on the Instrument Port
The factory configuration of the Isolator488 is as follows:

Section 2 Getting Started
2.3

Section 2 Getting Started
2.4
As shown in the preceding diagram, the Isolator488 is shipped with a 'soft ground'
consisting of a 1 MΩresistor in parallel with a 0.01 µF capacitor between local
Common and Earth Ground. This configuration should be suitable for most
applications. If you wish to make any changes to this configuration, follow the
steps given below.
2.3 Modifications
The Isolator488, as shipped from the factory, is configured for the typical use
of the unit which is to isolate the instrument port from Earth ground and from
Controller common. The factory configuration should be used unless you have a
significant variation in your application beyond galvanic isolation devices on the
Instrument port. If the factory configuration is not appropriate for your
application, the following procedures may be undertaken to modify the
Isolator488. It is necessary to open the enclosure to make any of the following
changes. If yoou have any questions about a particular change, please contact the
applications department at [phone].
1. Disconnect the power cord from the AC line and from the Isolator488.
Disconnect any IEEE cables prior to disassembly.
WARNING
Never open the Isolator488 case while it
is connected to the AC line. Internal
voltage potentials exist which could
cause personal injury or death.
2. Place the Isolator488 on a flat surface. Remove the six screws on top of the
case and remove the top cover. Located to the right of the Controller Port IEEE
488 connector are locations for C16, R4, and F2. Located to the right of the
Instrument Port IEEE 488 connector are locations for C59, R5, and F3. Refer to
the following figure:

Section 2 Getting Started
2.5
F2
JPR1 R4
C16
C47 C48
JPR2
F3
R5
C49 C50
C59
TO CONTROLLER TO INSTRUMENTS
Controller Port Common Components
Instrument Port Common Components
Isolator488 Internal View

Section 2 Getting Started
2.6
The following options are available on each port:
1. The Shield pin of the IEEE 488 connector (pin 12) may be connected to the
logic common of the IEEE 488 connector (pins 18, 19, 20, 21, 22, 23, and 24) or
left unconnected.
2. Logic common of IEEE 488 connector (pins 18, 19, 20, 21, 22, 23, and 24) may
be connected to the chassis of the Isolator488, connected to the chassis through a
soft ground, or left unconnected.
The following changes may be made to the Controller Port:
1. To remove the Controller common from earth ground, remove R4, and C16 by
either desoldering the components (the bottom panel or the Isolator488 must be
removed in order to do this) or cutting the component leads so that they may be
removed. Make note of this change for later reference.
2. To connect Controller common to earth ground, insert a 1/2 amp fuse in the fuse
clips labelled F2. The 1/2 amp fuse connects the Controller common to earth
ground and limits fault currents to 1/2 amp. Make note of this change for later
reference.
3. To connect pin 12 (shield) of the Controller Port to Controller Common, solder
a jumper wire in the location labeled JPR1. Make note of this change for later
reference.
The following changes may be made to the Instrument Port:
1. To add a soft ground between the Instrument Common and earth ground, insert
a 1 MΩ1/4 watt resistor in the location labelled R5. Insert a 0.01 µF 2kv ceramic
capacitor in the location labelled C59. Solder these components in place from the
solder side of the circuit board using rosin core solder. The bottom panel or the
Isolator488 will need to be removed in order to do this. Make note of these
changes for later reference.

Section 2 Getting Started
2.7
2. To connect the Instrument Common to earth ground, insert a 1/2 amp fuse in the
fuse clips labelled F3. Make note of this change for later reference.
3. To connect pin 12 (shield) of the Instrument Port to Instrument Common, solder
a bare jumper wire in the location labeled JPR2. Make note of this change for later
reference.
After making any changes to the Isolator488 internal circuitry, be sure to
document your changes then carefully reassemble the unit.
2.4 Line Voltage Selection
The Isolator 488 is designed to accept either 105 to 125 volt or 210 to 250
volt, 50 or 60 Hz, AC power. Each unit, when shipped from the factory, is labeled
with its input voltage setting. If this setting is not appropriate, the internal voltage
selection witch must be changed. Failure to operate the Isolator488 from
appropriate power source may result in damage to the unit. To check or change the
voltage selection switch disconnect all cables from the Isolator488 and follow the
steps below.
Isolator Fuse and Line Voltage Switch Locations
F1
S2
S1
WARNING :
LETHAL VOLTAGES
MAY BE PRESENT
115V
Power Connector

Section 2 Getting Started
2.8
WARNING
Never open the Isolator488 case while it
is connected to the AC line. Internal
voltage potentials exist which could
cause personal injury or death.
1. Place the Isolator488 on a flat surface. Remove the six screws on top of the
case and remove the top cover. Located next to the rear panel power connector is
switch S2 and fuse F1.
2. Insert the tip of a small screwdriver into the slot of the switch and move the
switch to the left or right so that the desired line voltage selection appears on the
switch. Make note of the new setting for later reference.
CAUTION
Use the 1/2 amp fuse, FU-1-.5, for 115
volt operation. Use the 1/4 amp fuse,
FU-1-.25, for 230 volt operation. Failure
to use the correct fuse could result in
damage to the Isolator488.
3. Replace the 1/2 amp fuse, FU-1-.5 (for 115 volt operation), with the 1/4 Amp
fuse (for 230 volt operation), part number FU-1-.25, that is included in the
Isolator488 Accessory Kit.
4. Carefully reassemble the unit.
WARNING
The Isolator488 is intended for INDOOR
USE ONLY. Failure to observe this
warning could result in equipment
failure, personal injury or death.

Section 2 Getting Started
2.9
2.5 Hardware Installation
Included with the Isolator488 Bus Isolator are accessories for rack or bench
use. If rack mount installation is required, install the two rack ears using the
enclosed screws. These ears can be installed so either the front or the rear of the
unit faces the front of the rack fixture.
View of Enclosure showing Rack Hardware Installation
Enclosure
Rack Ear
Top View
(2 per ear)
Enclosure
Top or Bottom View
Screw
If bench installation is required, the rubber feet can be installed on the
underside of the unit near each corner.
View of Enclosure Bottom Showing Feet Placement
Enclosure
Top View
Enclosure
Bottom View

Section 2 Getting Started
2.10
2.6 Operation
To begin operating the Isolator488, plug the power supply into the rear panel
jack. Apply power to the Isolator488 by depressing the rear panel power switch.
The front panel POWER LED should turn on.
If the POWER indicator does not light, there may not be any power supplied to
the interface. In this event, check to make sure the AC power is supplied to the
Isolator488, and that the power cord is properly installed into the unit. If the problem
is unresolved, refer to the Service Information section (Section 4) of this manual.
If proper operation is obtained, turn off the Isolator488 and connect the other
IEEE 488 devices to each of the Isolator488 ports. Apply power to all devices in the
system.
Once all IEEE devices have been connected and powered on, the Isolator488 will
allow the system controller to command up to 13 IEEE devices on its Controller Port
(in addition to itself and the Isolator488), and up to 14 IEEE devices on the Instrument
Port. The Isolator488 has no address of its own, and therefore will operate completely
transparent to the system. Be careful not to have two IEEE devices with the same
address connected to either ports. Failure to do so will result in the bus 'locking up'
when one of the devices is accessed.
2.6.1 Bus Loading
The IEEE 488 specification allows for a maximum of 15 bus loads.
The Isolator488 presents one bus load on each port. Therefore, an
additional 14 devices can be placed on each the CONTROLLER and
INSTRUMENT ports. Because the IEEE controller presents one bus load,
a total of 27 instruments, printers, plotters and other peripherals can be
accessed from a single IEEE controller.