Siemens SINAMICS G120 Operating Instructions Manual page 242

Functions
8.9 2-/3-wire control
Function
The STOP signal uses negative logic: Opening the contact or maintaining it open causes an
OFF1 condition and the drive stops. The STOP contact will need to be maintained closed to
start and run the inverter.
Then a momentary closure (positive edge) of the FWDP or REVP contact latches and starts
the inverter.
A momentary closure (positive edge) of the FWDP contact will set the forward direction.
A momentary closure of the REVP contact will change to the reverse direction.
Closing FWDP and REVP will cause a Stop (OFF1).
The ramp down can be interrupted by a single new pulse FWDP or REVP.
A momentary closure of the FWDP or REVP contacts while the drive is operating in the
respective direction will not cause any change.
Only by opening the STOP contact the drive will switch off regularly, apart from the special
case that both signals FWDP and REVP are present.
Figure 8-31
8-46
3-wire control using FWDP, REVP and STOP
Operating Instructions, 11/2006, A5E00766042B AA
Control Units CU240S