NSM-3E Signal Monitor Unit
Operations Manual
Eberle Design Inc.
Page 9
4.1.9 CLEARANCE INDICATOR
The CLEARANCE indicator will be illuminated when no Yellow or a short (less than 2.7
seconds) Yellow signal is detected on a channel during a Red to Green to Yellow to Red
sequence. The Channel Status display will show the active signals for each channel at the
time of the fault and the channels involved in the fault.
4.2 NO FAULT CHANNEL DISPLAY
When the NSM-3E is not in the fault state, the unit will continuously display the active
Green, Yellow, Walk and Red field status simultaneously on a four color LED full
intersection display.
4.3 FAULT CHANNEL DISPLAY
Once the NSM-3E has been triggered by a fault, the channel status display will alternate
between the field signals active at the time of the fault for 6 seconds, and the channels
which were involved in the fault (fault status) for 2 seconds. The channels involved in the
fault will flash their respective Green, Yellow, Walk and Red indicators simultaneously at a
4 Hz rate for the 2 second fault status interval.
If the fault displayed is a Recurrent Pulse Conflict, Recurrent Pulse Dual Indication, or a
Recurrent Pulse Red Fail, the RP STATUS indicator will then flash simultaneously at a 4
Hz rate with the input(s) that had Recurrent Pulse status for an additional 2 seconds
following the fault channel display.
4.4 RESET BUTTON
Depressing the Reset button resets the NSM-3E Signal Monitor after it has been triggered
by a fault. The monitor remains in the reset mode only if the fault condition has been
restored to normal. In the event of a monitor hardware or firmware fault (DIAGNOSTIC
indicator is illuminated) the Reset button may not reset the monitor.
