West Control Solutions Pro-EC44 - Manual (Page 90)

Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013 Page 83
13 Redundant Input
If the 2
nd
universal input is fitted, the second input can be configured as a redundant input for
the main process input. This increases process security by protecting against the possible
loss of valuable product resulting from sensor failure.
A second sensor is connected to input 2 so that if the main sensor fails, the instrument
automatically switches to this
backup or “redundant” sensor.
In this condition, if input 1 has a signal break alarm configured it will activate, but any other
process input or control status alarms seamlessly switch to the 2
nd
input. The 2nd input
continues to be used until the signal to input 1 is restored.
Note: The user may not even be aware of a sensor fault, so it is strongly
recommended that signal break alarms are configured for both inputs to provide
a notification if problems occur.
The redundant sensor must be of the same type, and be correctly located in the application
ready to take over if needed. If the redundant input option is selected, the 2
nd
input cannot be
used for other functions.
Note: If both signals are lost at the same time, the PV value display is replaced
with “OPEN” and the normal sensor break actions occur.