Compax3 device description C3I12T1180 192-120113 N08 C3I12T11 - December 20103.10.2. STO (= safe torque off) with Compax3SIn this chapter you can read about:STO Principle (= Safe Torque Off) with Compax3S ......................................................... 80Conditions of utilization STO (=safe torque off) Safety function ....................................... 82Notes on the STO function .............................................................................................. 82STO application example (= safe torque off) ................................................................... 84Technical Characteristics STO Compax3S ..................................................................... 873.10.2.1 STO Principle (= Safe Torque Off) with Compax3STo ensure safe protection against a motor starting up unexpectedly, the flow ofcurrent to the motor and thus to the power output stage must be prevented.This is accomplished for Compax3S with two measures independent of each other(Channel 1 and 2), without disconnecting the drive from the power supply:Channel 1:Activation of the power output stage can be disabled in the Compax3 controller bymeans of a digital input or with a fieldbus interface (depending on the Compax3device type) (deactivation of the energize input).Channel 2:The power supply for optocouplers and drivers of power output stage signals isdisconnected by a safety relay activated by the enable input "ENAin"(X4/3) andequipped with force-directed contacts. This prevents control signals from beingtransferred to the power output stage.The STO (= Safe Torque Off) safety function in accordance with EN ISO13849-1: 2008 PLd or PLe, Kat.3 is only possible when using both channelsvia an external safety switching devicePlease note the application examples!Circuit diagram illustrating working principle:controllersafety relayX4/3 X4/5X4/4 X1/1 X1/2 X1/3FeedbackpowersupplypowersupplymotorChannel 1 Channel 2L1 L2 L3Energize ControllerFeedbackENAin(Enable) FeedbackCompax3Notes In normal operation of Compax3, 24VDC of power is supplied to the "Enable"input (X4/3). The control of the drive takes then place via the digital inputs/outputsor via the fieldbus.
