Vacon OPTAF - Safe Stop 1 (SS1) principle

STO AND SS1 SAFETY FUNCTIONS vacon • 17
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3.2 Safe Stop 1 (SS1) principle
The Safe Stop 1 (SS1) safety function initiates the motor deceleration and initiates the STO after a
(user set) time delay.
Figure 5. The principle of Safe Stop 1 (EN 61800-5-2, SS1 type c)
The Safe Stop 1 (SS1) safety function consists of two safety related subsystems, an external time
delayed safety relay and the STO safety function. These two subsystems combined compose the
Safe Stop 1 safety function as shown in Figure 6.
Figure 6. Safe Stop 1 (SS1) safety function
Time
0
Stop
Motor
deceleration
Frequency
f
actual
Time delay
Safe Torque Off (STO)
11054.emf
Safe Stop 1 (SS1)
Time Delayed Safety Relay Vacon NX Safe Torque Off (STO)
+
Subsystem
Safety Relay
Subsystem
STO
11055.emf