2-Wire Control (P0727 = 1) - Siemens SINAMICS G120 Operating Instructions Manual

Functions
8.9 2-/3-wire control
Function
The ramp down phase can be interrupted by start command in the same direction: if the
drive was operating in forward and OFF1 was applied, an ON/OFF1 will work correctly and
accelerate again the drive up to the setpoint speed. The same is valid for reverse and
ON_REV/OFF1
Giving a start command for the opposite direction of which the inverter frequency output is
ramping down, the drive ignores the new setting and the drive will ramp down to 0 Hz and
then remain at standstill.
Without any control signal enabled the drive will ramp down to a stop and remain at
standstill.
Figure 8-29
8.9.2

2-wire control (P0727 = 1)

Description
This method uses two maintained signals, ON_FWD and ON_REV which start/stop the
inverter and determine the direction of the motor.
The advantage of this method of control is that ON_FWD and ON_REV can be switched at
any time, independently of the setpoint or frequency output or direction of rotation, and there
is no requirement of the motor to ramp-down to 0 Hz before the command is performed.
8-44
Siemens standard control using ON/OFF1 and ON_REV/OFF1
Operating Instructions, 11/2006, A5E00766042B AA
Control Units CU240S