Omega RS-422 User Manual

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User’s Guide

OMG-ULTRA-SIO

Dual Port Isolated/Non-Isolated
ISA RS-422/485 Adaptor Board

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It is the policy of OMEGA to comply with all worldwide safety and EMC/EMI regulations that
apply. OMEGA is constantly pursuing certification of its products to the European New Approach
Directives. OMEGA will add the CE mark to every appropriate device upon certification.

The information contained in this document is believed to be correct, but OMEGA Engineering, Inc. accepts
no liability for any errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, patient-connected applications.

Contents

INTRODUCTION..........................................................................1

OVERVIEW................................................................................................1

WHAT ’S INCLUDED................................................................................ 1

FACTORY DEFAULT SETTINGS ............................................................ 1

CARD SETUP ..............................................................................2

ADDRESS SELECTION.............................................................................2

PORT ENABLE / DISABLE.......................................................................2

IRQ SELECTION......................................................................................3

INTERRUPT MODES................................................................................4

RS-485 E NABLE MODES.........................................................................5

INTERFACE MODE EXAMPLES ............................................................. 7

LINE TERMINATION ............................................................................... 8

INSTALLATION ..........................................................................9

SYSTEM INSTALLATION........................................................................9

OPERATING SYSTEM INSTALLATION ................................................. 9

For Windows Users ............................................................................9

Other Operating Systems ...................................................................9

TECHNICAL DESCRIPTION.......................................................10

FEATURES .............................................................................................. 10

CONNECTOR PIN ASSIGNMENTS (DB 9 MALE)..............................10

SPECIFICATIONS ......................................................................11

ENVIRONMENTAL SPECIFICATIONS..................................................11

MANUFACTURING................................................................................11

POWER CONSUMPTION........................................................................11

MEAN TIME BETWEEN FAILURES (MTBF).....................................11

PHYSICAL DIMENSIONS........................................................................11

APPENDIX A - TROUBLESHOOTING .........................................12

APPENDIX B - HOW TO GET ASSISTANCEERROR! BOOKMARK NOT

DEFINED

.

APPENDIX C - ELECTRICAL INTERFACE ...................................15

RS-422.....................................................................................................15

RS-485.....................................................................................................15

APPENDIX D - GROUND LOOP PHENOMENON .........................16

WHAT IS G ROUND LOOP?...................................................................16

CABLING RECOMMENDATIONS..........................................................16

APPENDIX E - ASYNCHRONOUS COMMUNICATIONS................17

APPENDIX F - SILK-SCREEN.....................................................18

APPENDIX G - COMPLIANCE NOTICES ....................................19

FEDERAL COMMUNICATIONS COMMISSION STATEMENT ............ 19

EMC DIRECTIVE STATEMENT ........................................................... 19

Figures

Figure 1 - Address Selection Table....................................................................2

Figure 2 - Header E11 and E12, IRQ Select ion................................................3

Figure 3 - Header E5 & E6, Normal IRQ Mode ................................................4

Figure 4 - Header E5 & E6, Shared IRQ Mode.................................................4

Figure 5 - Header E5 & E6, Sharing IRQs with another adapter..................5

Figure 6 - RS-422..................................................................................................7

Figure 7 - RS-485 ‘Auto’ Enabled, with ‘No Echo’...........................................7

Figure 8 - RS-485 ‘Auto’ Enabled, with ‘Echo’.................................................7

Figure 9 - RS-485 ‘RTS’ Enabled, with ‘No Echo’...........................................7

Figure 10 - Headers E1 and E4, Line Termination..........................................8

Figure 11 - OMG-ULTRA-SIO cabling example............................................16

Figure 12 - Asynchronous Communications Bit Diagram..........................17

Introduction

Introduction

Overview

The OMG-ULTRA-SIO provides the PC with two additional ground isolated RS­422/485 (P/N 3189) or two non-isolated RS-422/485 (P/N 3089) serial ports for
terminals, modems, printers, etc. Isolation is important in installations where the
equipment being connected to the PC is either far from the PC, or on a different
power transformer circuit. Ground loop current is a commonly neglected and
misunderstood phenomenon that leads to data loss and t he possible destruction
of communications interfaces. The isolated OMG-ULTRA-SIO provides up to
500 volts DC of isolation.

What’s Included

The OMG-ULTRA-SIO is shipped with the following items. If any of these items
are missing or damaged, contact the supplier.

• OMG-ULTRA-SIO Serial I/O Adapter (P/N 3189 with isolation or

P/N 3089 without isolation)

• Software

Factory Default Settings

The OMG-ULTRA-SIO factory default settings are as follows:

Port # Base Address IRQ Electrical Specification

Port 1 3E8 5 RS-422
Port 2 2E8 10 RS-422

To install the OMG-ULTRA-SIO using factory default settings, refer to
Installation on page 9.

For your reference, record installed OMG-ULTRA-SIO settings below:

Port # Base Address IRQ Electrical Specification

OMG-ULTRA-SIO Page 1

Card Setup

Card Setup

The OMG-ULTRA-SIO contains several jumper straps that must be set for
proper operation.

Address Selection

Each port on the OMG-ULTRA-SIO occupies eight consecutive I/O locations. A
DIP-switch is used to set the base addres s for these locations. SW1 sets the I/O
address for port 1 and SW2 sets port 2. The following table shows the
addressing options available. If different address options are required, please
contact Technical Support about a custom PAL option.

1 2 3 4

3F8 On On On On
2F8 On On Off On
3E8 On Off On On
2E8 On Off Off On

2A0 Off On On On

300 Off On Off On
328 Off Off On On

Disabled Off Off Off Off

Figure 1 - Address Selection Table

Note: Each COM: port in the system should have a unique address. Typically

COM1: - COM4: addresses are 3F8, 2F8, 3E8 and 2E8 Hex.

Refer to Appendix A for common address contentions.

Port Enable / Disable

Each port on the OMG-ULTRA-SIO can be enabled or disabled with switch
position 4 on the DIP-switch. The port is enabled with the switch ‘On’ and
disabled when ‘Off’. If any port is disabled, be sure to disable the interrupt
request for that port by removing the IRQ jumper.

OMG-ULTRA-SIO Page 2

Card Setup

IRQ Selection

Headers E11 and E12 select the interrupt request for each seria l port. If COM1: is
selected, the corresponding jumper must be on the IRQ4 setting. If COM2: is
selected, the corresponding jumper must be on IRQ3.

Note: Most communications software applications default COM3: to IRQ4 and

COM4: to IRQ3. This requires the sharing of interrupts between COM1:
and COM3:, and between COM2: and COM4:. While this is the default, it
is not always the preferred setting. Check your software configuration
instructions to determine the most appropriate IRQ selection.

7

6

5

4

1514121110

3

2/9

Figure 2 - Header E11 and E12, IRQ Selection

Any two or more ports can share a common IRQ by placing the jumpers on the
same IRQ setting at header E11 and E12 and setting the appropriate selections at
E5 and E6. Note that a polling type driver is needed to share interrupts in this
fashion. Windows does not supply a polling type driver. Consult your particular
software for IRQ selection. If no interrupt is desired, remove the jumper.

OMG-ULTRA-SIO Page 3

Card Setup

Interrupt Modes

Header E5 and E6 selects the interrupt mode for each port. Each port must be set
in the correct mode to insure proper operation.

‘N’ indicates the (N)ormal, single interrupt per port mode. ‘S’ Indicates the
(S)hared interrupt mode, which allows more than one port to access a single IRQ.
Any two or more ports can share a common IRQ by placing the jumpers on the
same IRQ setting and setting the appropriate selections at E1. Consult your
particular software for IRQ selection. If no interrupt is desired, remove the
jumper. ‘M ’ indicates the inclusion of a 1K ohm pull-down resistor required on
one port when sharing interrupts.

N S M

1

2

Figure 3 - Header E5 & E6, Normal IRQ Mode

Set the jumpers to ‘S’ for shared interrupt mode on all blocks sharing an IRQ
except one. Set that port block for ‘M ’. This provides the pull-down resistor
circuit that makes sharing IRQs possible. If you are using more than one OMG-
ULTRA-SIO or a compatible adapter in a bus you should only have one port set
to ‘M ’. The following example shows both ports sharing a single IRQ.

E5

E6

N S M

1

2

Figure 4 - Header E5 & E6, Shared IRQ Mode

E5

E6

OMG-ULTRA-SIO Page 4