[?]: 24vac PLC inputs ?

[Jbeard]

I know that most PLC inputs are 24vdc,
but what would happen to the PLC if you applied 24vac to the inputs if it was a dc input?

[misa1515]

Hello,
24VAC on 24VDC input - value in PLC will flicker on 0 and 1

[Jbeard]

So that could be why we have alot of problems with these air handlers that are wired this way. The manufacturer says we don't know what where talking about.

[CoMod]

1. SIMATIC ET 200SP, digital input module, DI 8x 24 V AC...48 V UC
https://support.industry.siemens.com/cs ... 6cf00-0au0
6ES7131-6CF00-0AU0
ET 200SP, DI 8x 24VAC..48VUC BA, PU 1
https://support.industry.siemens.com/cs ... /109759596

2. use buffer relay, 24vac LZX:PT570524
https://support.industry.siemens.com/cs ... 3Apt570524