If you want Soft-I/O to provide device common or ground, you just select the common Soft-Device and then simply "wire" it by dragging and dropping the common connection to the proper Soft-I/O connector pin. What could be easier? Soft-I/O can provide up to one half amp of ground current per pin, up to a total of 4 amps into the Soft-I/O module. That's a lot of power handling capability for an I/O device!
The fact that Soft-I/O can provide device power might seem like a minor point. In fact, this subtle advantage of configurable Soft-I/O device power is a key reason that Soft-I/O dramatically simplifies wiring in your system.