Tolerance Window %, Relative - Siemens SIMATIC ET 200SP F-AI 4xI 0(4) 20mA 2-/4-wire HF Series Manual

Parameters/address space
4.3 Explanation of parameters
4.3.2.6

Tolerance window %, relative

Function
If you have selected "1oo2 evaluation (max. SIL3/Cat.4/PLe)", you can enter the size of a
tolerance window for the discrepancy here for each channel pair. You specify the tolerance
window as a percentage of the assigned standard value. The entered value is rounded to
one decimal place.
If two redundant input channels of the channel pair differ by more than the tolerance
specified here and for longer than the specified discrepancy time, the F-module detects a
discrepancy error and triggers a diagnostic interrupt.
The two parameters "Tolerance window % absolute" and "Tolerance window % relative" are
combined. The "Tolerance window % absolute" parameter is decisive in case of low process
values.
For more information regarding setting the tolerance window, refer to Parameter assignment
of discrepancy analysis for 1oo2 evaluation (Page 27).
Example
You have assigned the following:
● The "tolerance window % relative" is set at 10%
● A measuring range of 0 to 20 mA
● A discrepancy time of 200 ms
● A unit value of 20 mA
The input channels may differ from the configured discrepancy time (200 ms) up to the max.
reaction time for a time window with a difference of more than 2 mA.
See also
Discrepancy time (Page 24)
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Analog input module F-AI 4xI 0(4)..20mA 2-/4-wire HF (6ES7136-6AA00-0CA1)
Manual, 08/2018, A5E41448857-AB