Joe,
You cannot use the negative switched line from the robot / PLC to power othe 0 volts rail of my circuit. The 0V rail must be connected to the negative side of the 24 volt power supply. There must always be 24 volts between 0V and +24 on my circuit for it to work. On the diagram of the terminal strip in the robot that you posted in post #35 terminals 4, 10, 11 & 12 on the lower terminal strip MAY be the negative of the 24 volts supply. (I am hoping the "-" might mean negative.) You will have to trace the wiring in the robot to confirm this yourself (Or get some assistance on site.) We cannot help you with this.
Les.