Setting Smoothing Of Analog Values - Siemens S7-300 Installation And Operating Manual

9.3.15.1

Setting smoothing of analog values

Setting smoothing of analog values
You can set smoothing of analog values for this module in
Using smoothing
Smoothed analog values provide a reliable analog signal for further processing.
The smoothing takes place as a result of averaging over the selected number of conversion
cycles, e.g., 64.
The result may be a delay in a discrepancy with 1oo2 evaluation (see example below).
Smoothing principle
The measured values are smoothed by digital filtering. Smoothing is accomplished by the
module calculating mean values, derived from a defined number of converted (digitized)
analog values.
You assign smoothing in 4 levels (after 1, 4, 16, or 64 conversion cycles). The grade
determines the number of analog signals used for averaging. If smoothing = 1 conversion
cycle is assigned, 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 (see the example below).
Note
After startup, short circuit, wire break or exiting of the measuring range, smoothing is
restarted. If, for example, smoothing = 16 conversion cycles is assigned and all channels are
active, it takes up to 2000 ms at 50 Hz until the process value is signaled.
If a discrepancy occurs, measuring and smoothing continues and is not restarted.
Fail-safe signal modules
Installation and Operating Manual, 01/2010, A5E00085586-10
WARNING
9.3 SM 336; F-AI 6 x 0/4 ... 20 mA HART
HW Config
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Analog modules
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