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Principle
of Operation
The
input signal is first conditioned. If the input is an AC voltage
or current, this input is isolated and level converted by a
transformer and actively rectified. If the input is a DC voltage
or current, this input is filtered and conditioned to a suitable
DC signal. The input is then compared with a precision DC
voltage which can be adjusted by means of a potentiometer on the
lid of the housing. When the input level exceeds the set point
level, the comparator changes state and switches the output
relay.
Adjustable
dead band and delay circuits are provided to allow the user to
optimize the process control system.
These
process controllers have been designed to provide a totally
accurate and reliable method of monitoring and controlling
analogue variables. Two independent set points have been
designed into one housing – so as to provide two levels of
control - for alarms / shutdowns or minimum/maximum control.
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