How to Connect UPS

The RevPi Connect has a digital input that you can use to connect the status output of a UPS (uninterruptible power supply). You do not need an additional module, like the RevPi DIO or DI.

A UPS ensures that your devices continue to function during a fault. Depending on the type of UPS, it can protect your devices from the following interference:

  • power failure
  • overvoltage
  • undervoltage
  • frequency changes
  • harmonics

Please check if your UPS is suitable for connecting to the RevPi Connect.
Devices from the RevPi family have been developed for low-voltage operation. This means that you can apply voltages up to 30 V or currents up to 2 A.


If you apply a higher voltage, you are in danger of getting an electric shock and being critically injured.

To connect a UPS to your RevPi Connect, you must connect your power supply, the UPS, the RevPi and possibly I/O modules according to the specifications of the UPS. You can connect the status output of the UPS to the digital input on connector X2. Please observe the installation instructions of the UPS manufacturer.

Bit 6 of the RevPiStatus variable in the process image contains 0 or 1, depending on whether 0V or 24V are applied to the input. Your application must read this bit cyclically.  If the UPS reports a problem, your application must take appropriate action. What exactly should be done depends on:

  • the size of the battery used,
  • the power consumption of the RevPi Connect,
  • the current consumption of all components additionally connected to the UPS.

Typically, the system is brought into a safe state and the RevPi is shut down (sudo halt).


To make sure everything works in an emergency, you should do a test. To do this, create the following prerequisites:

  • The battery of your UPS is charged.
  • Your RevPi Connect and the UPS are connected correctly.

Now disconnect the power plug of your power supply. If the power LED on the RevPi remains green and your application responds as planned, your UPS will work.