Honeywell HC900 Reference Manual page 136

Function Blocks
DC Device Control Function Block
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.
122 HC900 Hybrid Control Designer Function Block Reference Guide Revision 11
2/07