System alarm contact inputs

Alarm contact inputs are physical input pins on the Alarms port that allow the operator to monitor and report changes in external environmental conditions. In a remote or outdoor deployment, alarm contact inputs typically allow an operator to detect specific conditions, such as, whether a door is open or closed, an air conditioner fault has occurred, and so on.

There are four input pins, each of which can be configured with an associated severity level and normal (default) state: normally open or normally closed. When an input pin changes state, the router can generate log events and raise facility alarms. There is a separate log event for each pin. The severity level of the input pin is controlled by configuring the severity level of the associated log event. The following command changes pin 1 to a severity of critical:

MD-CLI

configure log log-events chassis event tmnxSasAlarminput1StateChanged severity critical

classic CLI

configure log event-control chassis tmnxSasAlarminput1StateChanged generate critical

The normal state is configured as open or closed using the following command:

configure system alarm-contact-input normal-state

Nokia recommends the normal-state closed configuration so that an external power source failure triggers all the alarm pins to detect a change of state. If normal-state open is used with an external power source, an external power source failure does not generate any notifications.

WARNING: When an external, isolated DC power supply is used to source the voltage for any alarm, the negative rail must not be connected to the chassis ground and the rail should be 18 to 50 VDC at 100 mA.