OPTO 22 Optomux B1, Руководство пользователя

Страница: 10 / 33

B1 and B2 User’s Guide
5
5
3: 2: Introduction Chapter 3
2: Introduction
About Optomux
Optomux is a protocol used by a family of intelligent digital and analog I/O (input/output) units that
operate as slave devices to a host computer.
An Optomux I/O unit is a 4-, 8-, or 16-point assembly that accommodates optically-isolated analog
or digital I/O modules. Each Optomux I/O unit consists of a removable brain board and an I/O
mounting rack. The removable brain board contains a microprocessor which communicates with
the host computer and controls the plug-in I/O modules located on the I/O mounting rack.
There are two types of Optomux units: analog and digital. Any combination of analog I/O modules
may be plugged into an analog Optomux unit and likewise, any combination of digital I/O modules
may be plugged into a digital rack. Analog and digital Optomux units from the SNAP, brick, and
Classic rack families can then be combined on the same serial link, providing endless combinations
of analog and digital I/O points.
Optomux I/O units communicate with the host computer over an RS-485 serial communications
link. The serial data link is composed of two twisted pairs and a ground (5 wires) that connect to
each Optomux IO unit. It is possible to communicate with up to 256 individual units on a single
serial data link for a total of 4,096 digital and analog I/O points. This requires configuring all units
(B1’s and B2’s) in Repeat mode. However, this can also be accomplished with all units in Multidrop
mode, using a repeater (AC30) after every 32 nodes.
The RS-485 serial data link offers excellent noise immunity and long cable lengths. This can
dramatically reduce wiring costs by eliminating the need for bringing large bundles of field wiring
back to a central control location. Optomux units can be located where the actual control is needed.
The Optomux protocol and driver are described in form #1572, the Optomux Protocol Guide. This
guide is available on our Web site, www.opto22.com. The easiest way to find it is to search on the
form number.