Safe Torque Off 6-22 
AC30V series Variable Speed Drive 
Ensure the STO Request contacts are closed. 
Press the DRIVE START button. 
To perform operational (not STO) stop: 
Press the DRIVE STOP button.  
Wait for the motor to come to rest. 
To invoke STO: 
Press the DRIVE STOP button. 
Wait for the motor to come to rest. 
Open the STO Request contacts simultaneously. The contacts 
must remain open for the entire duration that STO is required: 
they must not be momentary action switches. The drive will 
confirm via X10/05 that STO has been invoked by the lamp being 
ON.  
If the lamp is OFF, do not access the machine as a fault may be 
present. 
Note: if the STO Request contacts open while the motor is 
rotating, the motor will coast to rest (unless external forces act on 
it). 
 
MINIMUM STO IMPLEMENTATION 
This example shows the minimum connections required. To reset from STO requires that STO Request contacts are closed to permit normal drive 
operation. The user must do a risk assessment to ensure that all safety requirements are met. The user must select and assess appropriate equipment. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Note: all wiring shown is within the control cubicle. 
 
AC30V STO