Siemens SIMATIC S7-400 Reference Manual page 260

Analog modules
5.21 Analog input module SM 431; AI 8 x 14 Bit (6ES7431-1KF20-0AB0)
Measured value smoothing
You will find information that is generally applicable to the smoothing of analog values in the
respective section. You can only set strong smoothing for the SM 431; AI 8 x 14 Bit.
The module cycle time is a constant, irrespective of how many channels are enabled. It
therefore has no effect on the filter settling time, which is defined by the parameter assignment
of interference frequency suppression and smoothing.
Filter settling time with strong smoothing
Table 5-54
Step response with strong smoothing
The following figure illustrates the contents of the table above. It shows the filter settling time
after which, in the case of a step response, the smoothed analog value is applied to almost
100%, depending on the interference frequency suppression that has been set. The figure
applies to every change of signal at an analog input.
Signal variation
in percent
Noise suppression
Figure 5-29
260
Interference frequency suppression and filter settling time with smoothing
Noise suppression
None
50 Hz
60 Hz
400 Hz
Step response for any analog input signal
100
63
50
12,5
0 30
400 Hz:
60 Hz:
50 Hz:
Step response of the SM 431; AI 8 x 14 Bit (6ES7 431-1KF20-0AB0)
Smoothing
Strong
Strong
Strong
Strong
83,333 100
60
Filter settling time in ms
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
Filter settling time in ms
-
100
83,333
12,5
120 150