Assuming the valve being controlled has limit switches which will signal a fully open, or fully closed position, the 2403 Valve Status Module operates in the following manner:

If the valve is closed, the green CLOSED indicator will be lit.  If the OPEN-CLOSE-AUTO pushbuttons are indexed to the AUTO mode, and an external contact closure signals  the valve to begin to open, the red OPEN indicator will begin to flash intermittently indicating the valve is to travel to this position.

As the valve begins to open, the green CLOSED indicating lamp will glow steadily, until the valve is fully open.  When the valve is fully open the TRAVEL lamp will go out and the red OPEN indicating lamp will glow steadily.

When operation is reversed and the valve is to close, the red OPEN indicator goes out, the green CLOSED indicator flashes, and the amber TRAVEL light glows steadily.  When the valve reaches a fully closed position, the amber TRAVEL light will go out and the green CLOSED light will go from a flashing to a steady state condition.

A time delay valve failure monitoring system is standard equipment, and is field adjustable from 0.2 to 60 seconds.  If the valve dies not operate within the specified time, the red FAIL indicating light will come on steadily.  When coupled with the Essex Model 2401 Alarm Module, the red FAIL indicator on the 2403 will flash and an  audible alarm will sound from the 2401.  By pushing the alarm button on either the 2401 or 2403, the alarm the alarm light will glow steadily.

An optional failure relay is available to activate external devices should a valve fail.

Auxiliary contacts are included on the OPEN-CLOSE-AUTO pushbuttons to provide remote monitoring of these switches, or to provide the capability for interlocking.  By using the electronic CONTROL output, or the FAIL output, a remote 24V DC relay can be used to provide additional contacts and higher current ratings where needed.