Siemens SIMATIC ET 200SP F-AI 4xI 0(4) 20mA 2-/4-wire HF Series - Page 37

Parameters/address space
4.3 Explanation of parameters
Analog input module F-AI 4xI 0(4)..20mA 2-/4-wire HF (6ES7136-6AA00-0CA1)
Manual, 08/2018, A5E41448857-AB
37
Example: Effect of smoothing on the maximum response time for a configured "1oo2 evaluation (max.
SIL3/Cat.4/PLe)" in case of error
If an error (One Fault Delay Time, OFDT) occurred with a configured "1oo2 evaluation (max.
SIL3/Cat.4/PLe)", you calculate the maximum response time according to the following
formula:
Maximum response time (in case of discrepancy error) = 2 × Conversion cycle time ×
Smoothing + Discrepancy time + 2 × Conversion cycle time
Example: One channel pair connected and configured (activated), interference frequency
50 Hz, smoothing = 16 conversion cycles, discrepancy time = 2000 ms, conversion cycle
time calculated with the formula from section Response times (Page 69):
Max. response time (in case of discrepancy error) = 2 × 70 ms × 16 + 2000 ms + 2 × 70 ms
= 4380 ms
If a discrepancy exists between the two input channels, it can take 4380 ms until the F-
module signals a discrepancy error to the F-CPU.
If the discrepancy time expires, an error is signaled and the process value is set to 7FFF
H
for
S7-300/400 F-CPUs or 0 for S7-1200/1500 F-CPUs. In the PII, the substitute value 0 is set
for the safety program.