Operate Control Relays Via SNMP
Send Control Commands to Remote Sites From Your NOC
Your master receives SNMP traps from your SNMP remote.
The SNMP remote is connected to all your remote devices
and is notified if an alarm is triggered.
Controlling remote-site equipment from your operations center saves you expensive windshield time, and allows you to respond instantly to on-site problems. In this application, the system operator can send control commands from your Network Operations Center (NOC) to the on-site SNMP remote. You can even set up certain controls to operate automatically when certain alarm conditions occur.
There are a few different ways to control a device remotely. Most commonly, you'll have a device that has a discrete input for receiving a particular command. This input will be expecting a dry contact closure from your RTU, which is exactly what most RTUs provide.
Imagine, for example, that you have a backup set of beacon lights on an antenna tower. Your monitoring system alerts you that the primary has failed. Instead of driving out the remote site just to flip on the backup lights (and potentially endangering aircraft and increasing your liability risk for an extended period), you can send a command to your RTU from your desk. The RTU will latch its control relay, which commands the backup light system's control box to activate the lights. This example can even be fully automated with a smart RTU.
A second type of control is the direct application/removal of power to a device. This generally requires a higher-amperage relay, because most standard RTU relays can support on 1 amp or less. This kind of remote control is useful when less aggressive control methods won't work. Many servers don't accept a dry contact for power control, and they might not respond if they're "frozen". Cycling power is one way around this problem.