Siemens SIMATIC ET 200SP F-AI 4xI 0(4) 20mA 2-/4-wire HF Series - Page 36

Parameters/address space
4.3 Explanation of parameters
Analog input module F-AI 4xI 0(4)..20mA 2-/4-wire HF (6ES7136-6AA00-0CA1)
36 Manual, 08/2018, A5E41448857-AB
Smoothing principle
The measured values are smoothed by a digital filter. Smoothing is achieved by the F-
module forming the mean of a number of converted (digitized) analog values determined by
the "Smoothing" parameter.
You assign smoothing in 7 levels (1, 2, 4, 8, 16, 32, 64 conversion cycles). The level
determines the number of analog signals that are averaged. If smoothing = 1 is configured,
the smoothing is deactivated.
A higher smoothing provides a more stable analog value, and prolongs the time it takes to
apply a smoothed analog signal following a unit step. You can find an example below.
Note
Smoothing is reset after startup, short circuit, wire break or another channel fault. If, for
example, smoothing with 16 conversion cy
cles is assigned and all channels are active, it
takes up to 2000
ms until the process value is signaled with a configured interference
frequency suppression of 50
Hz.
Until the first valid process value, the F
-module signals for the channel 7FFF
H
for S7-
3
00/400 F-CPUs or 0 for S7-1200/1500 F-CPUs.
If a discrepancy occurs, measuring and smoothing continues and is not restarted.
Example
The figure below shows the number of conversion cycles, depending on the smoothing
setting, after which the analog value is completely smoothed and available in the case of a
unit step. The figure applies to all signal changes at the analog input.
①
Smoothing - 4 conversion cycles
②
Smoothing - 16 conversion cycles
③
Smoothing - 64 conversion cycles