SNAP Serial

Communication Modules

PAGE

1

Opto 22 • 43044 Business Park Drive • Temecula, CA 92590-3614 • www.opto22.com

SALES 800-321-6786 • 951-695-3000 • FAX 951-695-3095 • sales@opto22.com • SUPPORT 800-835-6786 • 951-695-3080 • FAX 951-695-3017 • support@opto22.com

© 2006–2015 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

Features

SNAP-SCM-232: Two RS-232 serial ports with optional

RTS/CTS flow control

SNAP-SCM-485-422: Two RS-485 2-wire serial ports or

one RS-485/422 4-wire serial port

Individually isolated ports

Baud rates to 115 K Baud

Connection accessories provided

Works with the SNAP PAC System

Up to eight serial modules per rack

30-month warranty

Description

The SNAP-SCM-232 and SNAP-SCM-485-422 serial

communication modules are part of the SNAP PAC System.

They conveniently provide two channels of serial data at a

remote Ethernet location.

Many applications require digital, analog, and serial data to

provide a complete solution. Traditionally, either separate

serial network cabling is required for the serial devices, or an

expensive data processor or PC must be used just to interface

with the serial devices.

SNAP serial communication modules eliminate this problem

by providing two channels of high-speed, isolated serial

communications packaged in the compact SNAP module

form.

•

The SNAP-SCM-232 interfaces to auxiliary serial

equipment via two RJ-45 plug-in data connectors,

providing two RS-232 serial ports. The module also

supports optional RTS/CTS flow control.

•

The SNAP-SCM-485-422 uses the standard SNAP

removable top-mounted connector for easy wiring of

two 2-wire RS-485 ports or one 4-wire RS-485/422 port.

The module has convenient top switches for termination

and bias.

LED indicators are provided on each module to indicate

Transmit and Receive on each port.

Both SNAP serial communication modules work with SNAP

PAC Ethernet-based brains and rack-mounted controllers,

(They do not work with serial-based SNAP PAC brains.) These

modules snap into Opto 22 SNAP PAC mounting racks right

beside digital and analog modules, to provide the mix of

analog, digital, and serial channels you need at any location.

Typical applications include interfacing with printers, scales,

chart recorders, and barcode systems. Using the SNAP-SCM-

232 or SNAP-SCM-485-422 as a converter, these non-Ethernet

devices can be connected to an Ethernet network and be

available for control, monitoring, or data acquisition by any

authorized PC or other device on the network.

With the SNAP-SCM-232, two short (12-inch), unshielded

twisted-pair cables and two DB9 (male) adapters are included

for easy connection to all types of RS-232 devices.

SNAP racks use a retention rail locking system that holds

modules securely to the rack. Normally, a hold-down screw is

not required. However, for applications that require additional

module security, each module has provisions for two 4-40 by

½-inch standard machine screws to hold each module in

position on the SNAP rack.

For details on using these modules, see Opto 22 form #1191,

the SNAP Serial Communication Module User’s Guide.

Notes for legacy hardware: These SNAP serial

communication modules can also be used with SNAP Simple,

SNAP Ethernet, and SNAP Ultimate brains on an M-series or B-

series rack. SNAP-SCM-232 modules offering RTS/CTS flow

control were manufactured in June 2003 or more recently and

require I/O processor firmware version 5.0 or newer. The SNAP-

SCM-485-422 also requires firmware 5.0 or newer. An older

module part number, SNAP-SCM-485, supported 2-wire RS-

485 only.

Part Numbers

Part

Description

SNAP-SCM-232

Two-channel RS-232 serial

communication module

SNAP-SCM-485-422

Two-channel RS-485 (two-wire) or

single-channel RS-485/422 (four-wire)

serial communication module

SNAP Serial Communication Modules