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Off: Sets the Percent Cmd to 0% and sets the Instant Shutdown output to False. The MSC turns all outputs off, but only after all timers are satisfied.
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Max: The Percent Cmd is set to 100%. This value then feeds through the MSC and the stages turns on accordingly based on the timer settings.
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Limited Max: Set the output to the limited max value. This value then feeds through the MSC and the stages turns on accordingly based on the timer settings.
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Hold: Hold the Percent Command output at it’s current value. This value continues to feed to the MSC and the stages continue to be controlled by the sequencer. Should timers expire, it is possible for the number of enabled stages to change during a hold command since the Percent Command is really the only value that is explicitly held. If the Output Overridden is true, then the Output Position input is passed to the Heating Percent Cmd.
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Instant Shutdown: Sets the Percent Cmd to 0% and sets the Instant Shutdown output to True. The MSC turns off all outputs instantly.
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Control: Adjust the output to control the Process Variable. As this Percent Cmd varies, it causes changes to the enabling of the staged outputs from the MSC. If the input PID Tuning Reset is true, the Reset Tuning input to the PID is set to true causing the PID to recalculate its tuning parameters. While that occurs, the Heating Percent Cmd is held at its last value.
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Control Limit: Adjust the output to control the Low Limit Process Variable. As this Percent Cmd varies, it causes changes to the enabling of the staged outputs from the MSC.
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Failsoft: Set the output to the Failsoft value.
Proof of Airflow |
Mode |
PID Tuning Reset |
State |
---|---|---|---|
Fault |
* |
* |
Instant Shutdown |
NOT Fault |
Instant Shutdown |
* |
Instant Shutdown |
NOT Fault |
Off |
* |
Off |
NOT Fault |
Limited Max |
* |
Limited Max |
NOT Fault |
Max |
* |
Max |
NOT Fault |
Hold |
Reset 1st PID |
Control Limit |
NOT Fault |
Hold |
* |
Hold |
NOT Fault |
Control |
* |
Control |
NOT Fault |
Control Limit |
* |
Control Limit |
NOT Fault |
Failsoft |
* |
Failsoft |