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APPENDIX A – CONTROL TEMPLATES…
Process V
a
riable
di.1
Auto/Manual
Select
Master Output
ao1
•1
•2
•2
T
e
mplate 4 only
•1
T
emplate 3 only
.
Alarm
A1 trip value can be set to give the desired low signal detection
Digital Select
Manual Output
I/P2
Low Signal Select
(Alarm A1)
I/P1
OP1
…A2.2
Auto/Manual Station (Templates 3 and 4)
The
Auto/manual Station
provides a backup for a Master controller. In normal operation the COMMANDER 350’s current output follows the master
controller’s output value. A fault in the master system can be identified either by detecting a low signal on the master output
(template 3) or via a digital
signal (template 4). When a fault is detected the COMMANDER 350 selects manual mode with its output either set to the last vali
d master output value or
to a configured output value – see Section 4.6/ Control Configuration/ Configured Output 1. When the master signal is restored
or the digital input returns
to its normal state the COMMANDER 350 switches back to auto mode (i.e. COMMANDER 350 output = master output).
The auto/manual station can be used in series or in parallel with the master output signal – see Fig. A1. Parallel operation is
achieved by using relay 1 in
the COMMANDER 350 to energize an external relay (with suitable changeover contacts for switching low level signals) which selec
ts the output to be
routed to the actuator.