Siemens SIRIUS 3SK1

4 3 2 1
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Sensor:
① 3SK1220 input expansions
② 3SK1122 basic unit
③ 3SK1211 output expansion
④ 3RM1 Failsafe motor starter
Abbreviations in the following formulas:
GG = basic unit; EE = input expansion; AE = output expansion
In the event of shutdown by sensor 1, the total response time is calculated as follows:
• Basic unit = 40 ms
• 3SK1211 output expansion = GG + AE = 40 ms + 10 ms = 50 ms
• 3RM1 Failsafe = GG + 3RM1 Failsafe = 40 ms + 3RM1 Failsafe motor starter response time
In the event of shutdown by sensor 3, the total response time is calculated as follows:
• Basic unit = GG + EE 1 + EE 2 = 3 x 40 ms = 120 ms
• 3SK1211 output expansion = GG + EE 1 + EE 2 + AE 3SK1211 = 120 ms + 10 ms = 130 ms
• 3RM1 Failsafe = 120 ms + 3RM1 Failsafe motor starter response time
In the event of shutdown by sensor 4, the total response time is calculated as follows:
• Basic unit = 3 x EE response time + GG response time = 160 ms
• 3SK1211 output expansion = total response time EE with GG + AE = 170 ms
• 3RM1 Failsafe = 160 ms + 3RM1 Failsafe motor starter response time
Con󹪝guration / operation
9.4 Response times
SIRIUS 3SK1 Safety Relays and 3RQ1 Positively-Driven Coupling Relays
Equipment Manual, 05/2021, A5E02526190021A/RS-AE/005 181