Function Blocks
DC Device Control Function Block
122 HC900 Hybrid Control Designer Function Block Reference Guide Revision 11
2/07
Outputs
OUT =
Primary block output – the output is ON in the RUNNING and STOPPING states, else OFF.
RDY = (ready) ON when the control is in the Ready State (the controlled device is off and waiting for a
request to run), otherwise OFF.
PRES = (prestart) ON while in the prestart state (a request to run the device has been received and the start
delay timer is >0, otherwise OFF.
STRT = (starting) ON while in the start state (start timer has expired and there is a request to start the
device. The device feedback timer is started. The device is being monitored for failures),
RUN= (running) ON while in the Running state (the controlled device has completed start up (Device
Feedback) and is now running; occurs after the start delay timer expires; device is being monitored for
failures and feedback that it started) otherwise OFF.
STOP = (stopping) ON while in the Stopping state (the controlled device is requested to turn off; stop
delay timer is running; device is being monitored for failures, interlocking and returning to the run state),
otherwise OFF.
FAIL = (failed) ON when the control is in the Failed state (the controlled device reported a failure or did
not start up in time; device is being monitored for a manual or automatic reset), otherwise OFF.
DIS = (disabled) ON while in the Disabled state (the controlled device is locked-out; it cannot start running
until the disable input signal turns OFF), otherwise OFF.
STI = An enumeration representing the different states of the control.
Where: 0 = NOT USED, 1 = READY, 2 = PRESTART, 3 = STARTING, 4 = RUNNING,
5 = STOPPING, 6 = DISABLE, 7 = FAIL.
Conditions for transition from FAIL to READY state
One of the following conditions must occur to transition from the FAIL state to the READY state:
a)
If a Feedback error is the initial reason for the failure, then a manual reset is the only method for
returning to the Ready state.
b)
If Automatic-Reset is selected, then you return to the Ready state when Device Failure input
turns OFF.
c)
If Automatic-Reset is not selected, then you return to the Ready state when Device Failure input
is OFF and the Reset input transitions OFF to ON.
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