The INV_IOUT signal is a +/- 10V signal into the OZxxx-3000 board representing the full scale output/input current. The scaling can be whatever makes sense for your application – you just need to program the corresponding full scale value (i.e. what current is represented by 10V on the input pin) into the applicable configuration parameter. For example PID 0x0022 “INSTR_CURR_FS”, “Motor Phase Current Measurement – Full Scale” is used to scale this input on an OZMTR-3000 controller.