What about PNP-NPN / Source-Sinking for Inputs/Outputs ?

How to Connect 3-wire Sinking & Sourcing Devices to Ace PLC ?

If the common pin is + polarity, it’s called a sourcing circuit.  If it’s – polarity, it’s called a sinking circuit.

• Sinking:
  • provides a path to supply common (-)
  • must apply from 5 to 24 VDC on her input
• Sourcing
  • supplies a path to supply source (+)

About our Ace PLCS:

• Inputs are
• Outputs are

Wire the NPN output of my Ace PLC to a PNP input device

PNP input device means that the device is waiting for VDC on its input

Add a pullup resistor and this program (example for outputs D and E) at the beginning of your main program.