Remote Terminal Units (RTU) for Monitoring and Control

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RTUs like these enable you to remotely monitoring and control your facilities and equipment. You can collect self-reported equipment alarms and environmentals (temperature, humidity, smoke, water, etc.). You can track door and motion alarms. You can activate backup systems. If you want to monitor or control something without actually being there, there's probably a way to do it with a remote terminal unit.

An RTU with a big range of I/O

Let's take a look at this RTU to begin: the NetGuardian 832A. It's a good example, because it does a lot of things. If you understand this 832A, you understand remote terminal units.

RTU Features of the NG 832A:

• Discrete inputs - Monitor simple contact closures like equipment alarms, door sensors, floor water sensors, etc.
• Analog inputs - Monitor continuous values like the precise temperature, relative humidity, airflow speed, etc.
• Control relays - Control anything that accepts a discrete input. Activate generators, doors, lights, etc.
• Terminal server - Access legacy serial RS232/RS485 equipment over modern LAN
• +12v sensor power - Provide protected power at the standard voltage used by external sensors (ex. temperature, humidity...)
• Dual power inputs - Redundant power (ex. rectifier & battery plant) so your remote terminal unit keeps running during power failures
• 10/1000BaseT switch - Provide reliable LAN for other site devices without taking up more rack space or paying for an external switch.

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An RTU for small sites

Sometimes you only need a few inputs and outputs. There's no need to waste budget dollars on capacity you'll never use. The NetGuardian LT is a good solution in this scenario. With 2-4 discrete inputs, 1 analog, and 1 control, it provides reliable monitoring without going overkill on I/O.

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An RTU with built-in T1

Here's a medium-sized remote terminal unit with native T1 support (FrameRelay or PPP): the NetGuardian 216T. This is handy at outside-plant sites (especially microwave sites) where you don't have LAN. The included network switch also breaks out LAN for other devices. You know that's an incredibly valuable feature if you work with T1-only buildings.