January 2011
6 of 9
Impulse•G+/VG+ Series
3
Safe-Off 8001.x
PN:
140-10305
Configuring Safe-Off
Safe-Off requires a special control board and interface board which replace the standard control
and interface boards. The only significant difference between the boards is the additional BB,
BB1 and SN terminals. The standard drive performance and function is not affected by Safe-Off.
The BB and BB1 terminals run off the same 24VDC supply as the S1 ~ S8 terminals. However,
BB and BB1 do not require the drive’s processor to function. They are connected to hardware
buffers that block the gate drive signals from the processor to the IGBTs. A feedback circuit to
the processor is used to indicate an External Base-Block fault to notify the operator.
Figure 1: Safe-Off Circuitry
Figure 2: Normal Connection to
EN954-1 Category 3 Safety Device
BB
BB1
