Siemens SIMATIC PCS 7 Operating Manual page 156

Configuring the safety program
7.11 Monitoring times and system response times
F signal module
EM 8 F-DI Ex NAMUR
6ES7138-7FN00-0AB0
156
T
WCDT
With 1oo2 (2v2):
= 2 × conversion cycle time × filter + 2 ×
conversion cycle time + discrepancy time
E.g.: Interference frequency 50 Hz,
•
filter = 1 conversion cycle,
3 active channel pairs
= 2 × (3 x 25 ms + 50 ms) × 1 + 2 × (3 x
25 ms + 50 ms) + 1000ms = 1500 ms
Conversion cycle time = (Basic response time + N × response time per channel pair) (N
•
= Number of activated channel pairs)
Internal processing time
1oo1 evaluation
1oo2 (2v2) evaluation with discrepancy behav-
ior = "Provide 0 value"
1oo2 (2v2) evaluation with discrepancy behav-
ior = "Provide last valid value"
T
OFDT
Sensor supply test
Deactivated
22 ms
22 ms
35 ms
Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB
Sensor supply test
Activated
25 ms
25 ms
48 ms