Digital Inputs and Outputs (Compact)

The RevPi Compact has eight digital inputs and eight digital outputs.

You can access them either with piControl or without piControl: with piControl they are synchronized with the process image cyclically every 250 µs.

Digital Inputs

With the digital 24 V inputs, you can forward signals to the controller that are determined by a sensor, for example.

The inputs can withstand a voltage of up to 36 V. The switching threshold up to which “low” is guaranteed to be measured is 7 V, “high” is guaranteed to be measured from 10.2 V. The inputs are not galvanically isolated. A separate terminal is available for connecting the ground.

Above each digital input is an LED that lights up when the input is “high”.

Debouncing is possible in four stages: 25 µs, 750 µs, 3000 µs or no debouncing. The debouncing can only be set for all eight inputs together.

The inputs detect an excess temperature (135°C): a warning is then issued in the kernel log and a status bit is set in the piControl process image.


Digital Outputs

Unlike the inputs, the eight digital 24 V outputs are galvanically isolated. This makes it possible to operate them via an independent power supply. Always use the same ground potential that supplies the connected sensors or actuators. However, the same power supply as that of the RevPi Compact can of course also be used. The voltage supply of the digital outputs must be at least 12 V and must not exceed 36 V.

The digital outputs are protected with an automatic switch-off in case of overtemperature. This switch-off applies separately to each individual output.

Above every digital output there is an LED that lights up when the output value is “high”.

Attention: the outputs are monitored by a watchdog and set to “low” if they are not rewritten every 9 ms. This is to ensure that the outputs are brought to a safe state, for example in the event of a system crash. In this case their LEDs will no longer light.