WAGO-I/O-SYSTEM 750
Device Description
45
753-668/000-004 4FAI 0/4-20 mA Diff PROFIsafe
Manual
Version 1.0.0, valid from HW/SW Version 01/01
3.6.10.3.1.2 Secure Non-Detection of a Discrepancy Timeout
The following formula can be used to calculate the maximum actual discrepancy
time between two input signals
Tn
D,max
as a result of which the F-AI module will
certainly report no discrepancy error.
𝑻
nD,max
= Discrepancy Time × 𝟎. 𝟗𝟖𝟕𝟔𝟕 + 𝑻
GAnD
Factor
Value
T
nD,max
Maximum actual discrepancy time between two input
signals
Discrepancy Time
Configured discrepancy time
Discrepancy Factor
0.98767
T
GAnD
Offset defined by smoothing and sampling
– see table
below for exact values
Table 25:
T
GAnD
: Offset Defined by Smoothing and Sampling
T
GAnD
Sampling Frequency in Hz
100
60
50
10
S
moothi
ng
i
n
nu
mber
o
f
sa
mpl
ing
va
lue
s
1
−6 ms
−8 ms
−8 ms
−31 ms
2
1 ms
3 ms
6 ms
46 ms
4
17 ms
28 ms
37 ms
203 ms
8
48 ms
79 ms
100 ms
516 ms
16
111 ms
179 ms
225 ms
1142 ms
32
236 ms
378 ms
476 ms
2394 ms
64
486 ms
779 ms
977 ms
4899 ms
Note the suitability of the parameter combinations!
If
T
nD,max
≤ 0
, then the selected parameter combination is unsuitable because
irrespective of its duration a discrepancy of the input signals can potentially lead
to a discrepancy error.