External Power Supply For The Control Unit (Xpow); Safe Torque Off (Xsto); Fso Safety Functions Module Connection (X12) - ABB ACS880-304LC Series Hardware Manual

8) Determines whether DICOM is separated from DIOGND (ie, common reference for digital inputs floats).
DICOM connected to DIOGND
DICOM and DIOGND separate

External power supply for the control unit (XPOW)

The control unit is powered from a 24 V DC, 2 A supply through terminal block XPOW.
Using an external supply is recommended, if:
• the control unit needs to be kept operational during input power breaks, for
example, because of continuous fieldbus communication
• immediate restart is needed after a power break (that is, no control unit power-up
delay is allowed).

Safe torque off (XSTO)

Note: The XSTO input only acts as a true Safe torque off input on the inverter control
unit. De-energizing the IN1 and/or IN2 terminals of other units (supply, DC/DC
converter, or brake unit) will stop the unit but not constitute a true safety function.

FSO safety functions module connection (X12)

Refer to the applicable FSO module user's manual. Note that the FSO safety functions
module is not used in supply, DC/DC converter or brake units.
The control unit 135