TIA portal V10.5: Input a filter on the analog input to reduce instability

Reagan40

How do I put a filter on the analog inputs for the S7 1200, I have already set the input for the maximum number. Any suggestions?

Reagan Wiseman

Pegaia

Hi,

by hardware definition, you have two places to act: Noise reduction - integration time (up to 100ms) and smoothing (up to 4 cycles).

If you need more than that, you need to mount a subroutine that make an additional software smooting.
A general formula is:

OUT = k * IN (ST/T) + LAST_OUT * (1 - ST/T)
IN= analogic input
OUT = filtered output
LAST_OUT = filtered output (from the previus call)
T = cicle time (OB time)
ST = Time constant
k = proportional factor (optional)