BECKHOFF AX2000 PROFIBUS DP communication profile - Manual (Page 46)

After the homing run has been completed, Bit 11 STW must be set to 0 again.
Alternatively, the reference point can also be set at the actual position.
This can be achieved by setting Bit 12 STW, or by setting the homing run type 0 with PNU 1773 and
subsequent start of the homing run by Bit 11 STW .
46 PROFIBUS for AX2000/2500
Appendix
12/05
BECKHOFF