40
Device Description
WAGO-I/O-SYSTEM 750
753-668/000-004 4FAI 0/4-20 mA Diff PROFIsafe
Manual
Version 1.0.0, valid from HW/SW Version 01/01
3.6.10.1.1 Safety Response Time of Analog Inputs in an Error-Free Case
In the error-free case, the response to the signal change is that the input process
value of the input channel passes a threshold. The input process value
approaches the final value asymptotically after the signal change of the analog
input signal. The response time therefore increases exponentially, the closer the
threshold is to the final value. In response to the signal change, reaching 90% of
the difference between the input process value before the signal change and the
final value (t
2
) is defined as the threshold value (see Figure “Definition of the
Safety Response Time of the Analog Inputs in an Error-
Free Case”).
Figure 9: Definition of the Safety Response Time of Analog Inputs in an Error-Free Case
The safety response times are listed in the table “Safety Response Time of the
Analog Inputs T
SR
Depending on the Sampling Frequency an
d Smoothing.”