Safe Torque Off (STO) / Interlock

Servosila SC-120R servo drives come with a "Safe Torque Off / Interlock" port for safety-critical applications.

The STO function disconnects the motor from power at the "bare metal" level. This function makes sure that dangerous machines do not move during maintenance or when not in use, even if firmware, network, an upper layer control system or operators "go crazy".

Whenever the STO pin is low, the STO circuitry physically disconnects the inverter's power switches from the motor. The motor starts coasting. The servo drive itself stays operational.

The same port can be used to "interlock" a master motion control board with its slave servo drives. If the master control board looses power or malfunctions, the voltage on STO pins goes low, the #servo drives are forced to stop.

The STO/Interlock function can be disabled by removing a jumper, when not employed in an application.