Knowledge Base:  
Tech Note 104: Wiring Relays with Common Alarms
Last Updated: 05/10/2017
Wiring Relays with Common AlarmsCMCP500 (A) Series Monitors may be wired either with individual alarms or with common alarm outputs grouped by machine or system. When wiring common alarms the OK (normally energized) circuit is wired in series using the normally closed (NC) contacts. On a loss of sensor OK or power the OK relay will change state opening the circuit. Closed = OK, Open = Not OK.

As an alternative the OK circuit could also be wired in parallel (as Alert and Danger are shown) using the normally open side of the relay in which case. Open = OK, Closed = Not OK.

Alert and Danger common alarms (normally de-energized) are usually wired in parallel using the normally open (NO) contacts. An alert or danger vibration alarm will close the respective circuit. Open = No Alarm, Closed = Alarm.

On CMCP500 Series Monitors the OK relay is normally energized and the Alert and Danger relays are normally de-energized.

On all CMCP500 Series Monitors the OK relay terminals are located on the lower right front and the Alert and Danger relay terminals are found on the plug-able terminal located on the bottom of the monitor.

Common Alarm Example:

Wiring Common Alarm Relays

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