Why do Siemens LOGO! Ethernet I5/I7/I8 inputs latch relay until repeats?

Welcome,

Dear forum members! I have 3 Siemens LOGO version controllers with Ethernet and to each 3 I/O expansion modules (the ones with relays).

Everything is supposed to control a smart home and so far everything works as expected except for one strange phenomenon. Well, in each of the controllers, several inputs and outputs are used to switch on the lights in the house. And this is where the problem arises. On some inputs it simply doesn't work. With the simplest configuration like: INPUT -> multiswitch -> OUTPUT the controller switches on e.g. a relay, but no longer wants to switch it off. If I press the button which short-circuits the input several times, the relay finally releases its position. And so on non-stop. If I change the input to another one, the problem disappears.

At first, I thought the problem was with inputs I7 and I8, because in these controllers they have two functions (analogue and digital). But the problem also appeared on input I5 in one controller.

Has anyone encountered this problem? Could it be an input failure?

Regards and hoping for hints

It could be a problem of oscillating contacts - think pressing a key once and getting a string of pulses on the input?! You need to 'desensitise' the inputs by software.

Exactly, I've solved the problem already a few days ago The problem was that I used twisted-pulse control and these behaved like coils at such distances. A simple software circuit (RC) sorted it out and everything works as it should