GE GFK-0787B Noise Reduction Machine User Manual


 
7
7-19GFK-0787B Chapter 7 Programming Information
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| << RUNG 12 >>
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|IORESIP IORES
|——|# |—————————————————————————————————————————————————————————————————(R)———
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| << RUNG 13 >>
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|LOGONFT FORCLOG
|——|# |—————————————————————————————————————————————————————————————————(R)———
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| << RUNG 14 >>
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|DUPLEX LOGONFT FORCLOG
|——| |—————| |——————————————————————————————————————————————————————————(S)———
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|TRIPLEX IORES
|——| |——— ————————————————————————————————————————————————————————(S)———
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|–END:
In rung 12, the transition of IORESIP (I/O Reset in Progress) to the Off
state indicates that the requested I/O fault reset has been completed.
This rung resets command bit IORES (I/O Reset) to the Off state.
In rung 13, the transition of LOGONFT (Logon Fault) to the Off state
indicates that the requested I/O fault reset has been completed. This
rung resets command bit FORCLOG (Force Logon) to the Off state.
In rung 14, if the GMR system is in DUPLEX mode (two CPUs are on
line) and a logon fault occurs at an output block, LOGONFT turns on.
This turns on the Force Login (FRCLOG) control bit, which forces the
output block to accept outputs from the newly-online CPU, even if the
output states do not agree with the present voted outputs at the
output block. This logic also turns on the control bit IORES (I/O Reset).
IORES is required to clear the Logon Fault status bit (LOGONFT). This
last action also clears the fault tables in all running PLCs.
The TRIPLEX bit is optional; the need for this bit depends on the
application. If used, it provides the same type of PLC logon control
when a third PLC comes on line.
Caution
Depending on the application, you may prefer to use only the DUPLEX logic shown
above to turn on the FORCLOG (Force Logon) command bit. The purpose of PLC logon
control is to prevent a CPU that is coming online from changing the state of a critical
voted output. Automatic PLC logon is sensible with the DUPLEX status bit, because it
ensures that at least two PLCs are driving output information before outputs that
disagree with the voted outputs are used when a system is initially powered up. The
third PLC coming online has the ability to change an output state if the first two PLCs
are already online and already disagree. Because of this, it may not be suitable to
“automatically” log on the third PLC.