IFM Electronic AC402S - Page 96

SmartPLC SafeLine AC4S with fieldbus interfaces
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Step 2: Calculate the response times of the safety function
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► Make measurements for a real system.
► Ensure sufficient dimensioning of the watchdog times and task monitoring.
► Measure the maximum response time in all sections of the signal propagation path with safe
fieldbus communication or safe cross communication.
 safe fieldbus communication (FSoE): output tMaxRespTimeMS of the function block
FSoEMaster
 safe cross communication (Safety NetVars): output tMaxRespTime MS of the function block
NetVarReceiver
► Calculate the response time of the safety function with the measured values:
 without safe cross communication:
AS-i output
Local output
FSoE slave output
AS-i input
-
-
30 ms +
2*T(SafetyTask) +
tMaxRespTimeMS(FSoE_out)
Local input
-
-
16 ms +
2*T(SafetyTask) +
tMaxRespTimeMS(FSoE_out)
FSoE slave
input
tMaxRespTimeMS(FSoE_in) +
2*T(SafetyTask) +
15 ms
tMaxRespTimeMS(FSoE_in) +
2*T(SafetyTask) +
8 ms
tMaxRespTimeMS(FSoE_in) +
2*T(SafetyTask) +
tMaxRespTimeMS(FSoE_out)
 with safe cross communication:
To device 2
From device 1
AS-i output
Local output
FSoE slave output
AS-i input
30 ms +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
15 ms
30 ms +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
8 ms
30 ms +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
tMaxRespTimeMS(FSoE_out)
Local input
16 ms +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
15 ms
16 ms +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
8 ms
16 ms +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
tMaxRespTimeMS(FSoE_out)
FSoE Slave
Eingang
tMaxRespTimeMS(FSoE_in) +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
15 ms
tMaxRespTimeMS(FSoE_in) +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
8 ms
tMaxRespTimeMS(FSoE_in) +
2*T(SafetyTask_Dev1) +
tMaxRespTimeMS(SafeNetVars) +
2*T(SafetyTask_Dev2) +
tMaxRespTimeMS(FSoE_out)
The formula in the table determine only the maximum response time of the devices. For the
calculation of the maximum process response time the delay times of the safety AS-i
sensors/actuators and the respective input/output devices have to be added additionally
(T(sensor) + T(input) and T(output) + T(aktuator)).