Safety Response Time Of Analog Inputs For Two-Channel Applications With Discrepancy Monitoring; Figure 11: Response Time For Discrepancy Monitoring - WAGO 753-668/000-004 Manual

42 Device Description
3.6.10.3 Safety Response Time of Analog Inputs for Two-Channel
Applications with Discrepancy Monitoring
The response time for discrepancy monitoring (T
duration of a range overflow for one channel of the channel pair outside the
defined tolerance band (time t
) (see Figure "Response Time for Discrepancy Monitoring"). The input
(time t
2
process value approaches the final value asymptotically after a signal change at
the input. The response time thus depends on the difference between the
discrepancy threshold and the final value of the signal change. The smaller the
distance between the discrepancy threshold and the final value, the greater the
response time. When considering the response time for discrepancy monitoring,
it is assumed that the discrepancy threshold of the tolerance band is 90 % of the
final value of the signal change.

Figure 11: Response Time for Discrepancy Monitoring

The response time for discrepancy monitoring is calculated with the formula:
Factor
T
FR
Discrepancy Time
Discrepancy Factor 1.02466
T
GA
Manual
Version 1.0.0, valid from HW/SW Version 01/01
753-668/000-004 4FAI 0/4-20 mA Diff PROFIsafe
) and the response in the input process image
1
�� = Discrepancy Time × ��. ���������� + ��
FR
Value
Response time for discrepancy monitoring
Configured discrepancy time
Offset defined by smoothing and sampling – see table
below for exact values
WAGO-I/O-SYSTEM 750
) corresponds to the maximum
FR
GA