OPTO 22 G4LC32, Руководство пользователя

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G4LC32 User’s Guide
I/O Units (Bricks)
The G4LC32 Model 200 Processor not only handles all the logic to run your application programs but it communicates
with I/O units (Bricks) as well. The G4LC32 Model 200 Processor connects to I/O units in two different ways: (1) you
can use local I/O units which communicate with the G4LC32 over a 1.4 MHz parallel bus (a 34-conductor, flat-ribbon
cable), or (2) you can use remote I/O units which communicate with the G4LC32 over a two-wire RS-422/485 serial
communication link operating at up to 115.2 KBd.
The advantage of local I/O is speed (1.4 MHz, ~1.5 Mbps). The disadvantage is that the total bus length is limited
to 200 feet. As many as 139 local I/O units can be connected to one G4LC32. You scan mix and match both digital
and analog I/O units, as needed by your application. Each I/O unit can have up to 16 I/O points (modules), thus one
G4LC32 can control up to 2,224 I/O points on the local bus. CRC 16-error detection is included in every message
transaction to insure safe, reliable operation. If longer distances and/or more I/O points are required, then panels
containing remote I/O units may be added to the system.
The advantage of remote I/O is that you can distribute your I/O units over large distances. The G4LC32 and the
remote I/O units can be separated by distances up to 3,000 feet (even longer distances with repeaters). The
disadvantage is a slower baud rate of 115 KBd. You can use a single twisted pair of wire to provide cost-effective
communications over an RS-422/485 communications link. A Mistic controller supports three remote I/O links and
one host communication link, or four remote I/O links when ARCNET is used for host communications. Four remote
I/O links can be used in stand-alone applications. As many as 100 (256 with repeaters) remote I/O units can be
connected to each remote I/O link. CRC 16-error detection is included in every message transaction to insure safe,
reliable operation.
Each I/O unit contains a brain board with its own powerful 16-bit 80C196 processor. The processor in the I/O unit
performs an incredibly useful set of common control functions like high speed counting and PID control at the brain
board level. As a result, the unburdened G4LC32 Model 200 Processor can execute control logic with remarkable
speed.
Software
The G4LC32 Model 200 Processor provides support for Cyrano 200 and OptoControl. It runs a multitasking kernel
which can run up to 32 separate charts (tasks) simultaneously. A complicated control application can be segmented
by functions enabling each function to be represented by its own unique chart.
Communications
The G4LC32 features four serial ports; two switch-selectable RS-422/485 or RS-232 ports and two
RS-422/485-only ports. Baud rates from 300 to 115 K can be selected by means of the front panel keypad.
Any of the four serial ports or ARCNET port can be used for communications to a remote PC workstation. The
RS-422/485 ports would typically be used when several serial devices must be connected to one serial communication
line. As many as 100 devices can be connected to a RS-422/485 port in a multidrop application. Other typical uses
for the RS-422/485 port are (1) for applications requiring a high degree of noise immunity, (2) the capability of
transmitting over longer line lengths (up to 3000 ft.) and (3) transmission at higher baud rates.
INTRODUCTION
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