INFICON SQC-222 Thin Film Deposition Controller - Manual (Page 64)

Chapter 3 Menus
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3.10 PLC I/O
The standard I/O of the SQC-222 is adequate for most applications. Applications that
require additional I/O points, or extensive I/O logic capabilities, can use the low cost
PLC option to extend the instrument’s process control capabilities.
An inexpensive Omron CPM2 series PLC extensive I/O processing capabilities through
its ladder logic programming.
There are several benefits to using the PLC. First, noisy high voltage wiring can be
placed near the control sources, rather than routed to the SQC-222 controller back
panel. Only a single serial cable runs from the PLC to the SQC-222. The PLC also
provides electrical isolation from the process for the SQC-222. And finally, the PLC’s
ladder logic programming provides fail-safe process protection and allows I/O to be
easily tailored to each end user’s installation.
The functions of the standard PLC program supplied by Sigma extend the SQC-222
standard I/O as shown below:
PLC Input 0.00 to 0.11 Functions mapped by SQC-222 system setup screen
1.00 Pocket ready signal from Indexer 1
PLC Relay 10.00 to 10.07 Functions mapped by SQC-222 system setup screen
11.00 to 11.03 Pocket 1 to 4 select signal for Indexer 1
The PLC runs a small ladder logic program that communicates with the SQC-222
through several internal registers on the PLC. These PLC registers contain information
about the SQC-222 operating state, the selected sensors and outputs, and indexer
status. The ladder logic program can be modified to perform additional I/O, logic and
timing functions using Omron’s CX-Programmer software. Contact Sigma Instruments
for more information on programming your PLC.