The Compax3M Servo Drive/Controller doesn't come with STO and is not available on modular Compax3M models.
Certified Category 3 Safety (EN954-1 Cat. 3)
It is recommended that you program the unit to ramp down for a controlled deceleration and trigger this block of code with an input signal to execute. Then an output signal can be used to open up the control power after a brief delay with controlled deceleration.