I'm using a Controllino Mega (CONTROLLINO MEGA – CONTROLLINO) for a automation project. I have to control some doors and semaphores.
All signals are 12VDC and the Controllino is powered with 12VDC.
I have some trouble because some inputs somehow get a dirty logic state when the input circuit is open.
For example I have an emergency button normally closed, when I push it, the circuit opens leaving the input wire without any signal.
The Controllino detects an input and the logic state stays on with an open wire. Its led is not fully on, but brights softly. When I close the circuit releasing the button, the bright is full, when I push it (opening the circuit) the bright the softer.
I tought it can be a noise in the open wire, the wire is about 20-30m long and passes near other signals, 220V, solenoids for door locks etc.
Then I was woundering if the Controllino digital input needs a pull-down resistence or something like this like an Arduino, I did not find anything about these specification in the Controllino datasheet and honestly I would expect an automatic handling about input from a PLC, but maybe I'm wrong and I need a pull-down configuration too.
Do you have any idea about this problem?
Thanks for your help.