Rockwell Automation 1771-PM , D17716.5.18 U MNL 1771-PM CLUTCH/BRAKE MOD - Manual (Page 40)

Chapter
5
5Ć1
Voting Processor Firmware
This chapter will help you become familiar with:
operation of your voting processor firmware
operational sequences for controlling your press
A clutch/brake controller has two clutch/brake modules, one in chassis A
and the other in chassis B. Each clutch/brake module contains firmware
that makes it function as a voting processor. Both voting processors
contain identical firmware programs that independently monitor your
clutch/brake controller I/O while controlling the press.
While running their firmware programs, both voting processors constantly
“vote” on the status of your press. Both voting processors must always
have a consensus. If they find that they don’t agree on their perceived
conditions of your press, they either stop the press or prevent it from
starting.
Also, both voting processors constantly check their communication
channels. Press motion is stopped or inhibited if either voting processor
detects a loss of communications with the PLC or the other voting
processor. A failure in one voting processor is immediately seen as a
communication loss by the other voting processor.
Finally, voting processors control the operational sequences that your
operators must perform in inch, single, and continuous modes.
Each voting processor (PM module) controls one seal relay and one
crowbar relay. All E-STOP switches are connected in series with seal
relay contacts. If any of these contacts opens or if the PM module detects
a trip condition, solenoid power is disconnected. If a PM module detects
that solenoid power should be off when on, it turns on the crowbar relay
to blow the solenoid power line fuses. At clutch/brake start, both PM
modules test their crowbar relays without blowing the line fuses. Wiring
diagrams in chapter 6 show these connections.
Chapter Objectives
Operation of Voting Processors
Emergency Shut Down