CPU224 OUTPUT INTERNAL RELAY STUCK PROBLEM

Hello,

In 18month every relay have 580kcicles.

as you can see in technical data max (teoric) number of operation for relay is 100kcicle at rated voltage .

also considering 10Mcicle (mechanical limit) you hare near the end of relay life.

Also switching frequency is out of max (1Hz that means 0,5sec on and 0,5s off).

In my opinion you have to use plc with electronic digital output (if you like s7-200 there is 214-2AD23) and solid state relay.

P.S. actually do you have parallel diode in relay coils???

Best Regards

parallel diode may help.

But in any case relay output is not te best solution

Best Regards