Dear Expert,

I have a used function block in different PLCs for analogue input and reading arithmetic fault by comparing analogue scaled value with DW#16#7F800000. All are okay except one. One PLC is giving time to time "Signal fault" of the different analogue inputs randomly . I have attached the snap of the FB network. Please support what could the reason behind this signal fault and what will be the solution. Thank you.

Best Regards,

Ahmed

One question.

Are you trying to compare Real with Hex here in a CMP_R function?

If so it won't work, try converting the Hex number to Real.

Dear Chulien,

Behind SET we have an always high bit. The analog value getting infinity for short time and due to that we are getting "Signal fault".

Best Regards,

Ahmed