Siemens S7-300 - Page 274

Analog modules
9.3 SM 336; F-AI 6 x 0/4 ... 20 mA HART
Fail-safe signal modules
274 Installation and Operating Manual, 01/2010, A5E00085586-10
"Tolerance window %, absolute" parameter
You can calculate the absolute tolerance window using the following formula:
7
DEV

ෙ,
DEV
,
0(
෥,
0$
>@
Calculate the maximum deviation of the current using the following formula:
,
0(
෥,
0$
7
DEV
ෙ,
DEV
 s >P$@

With
● I
ME
= 20 mA
● I
MA
= 0 mA for measuring range 0 ... 20 mA
● I
MA
= 4 mA for measuring range 4 ... 20 mA
● T = Tolerance, in %
● ΔI
abs
= Maximum deviation of current (+/-)
You can assign a value of 0.2 to 20% for the "Tolerance window %, absolute" parameter for
each channel pair.
W
,>P$@


W
,>P$@



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Figure 9-41 Absolute deviation in % of the nominal range for measuring range 0 to 20 mA or 4 to 20 mA