Data input and output using various forms of signal and ports provides no problems for the GF-2000 system.
Digital signals can be read in parallel or serially. Even an interface conversion is possible. The digital inputs are able to recognize both positive and ground.
The analogue signals are read in and out as voltage signals, current signals and PWM signals. Connect your transducers and proportional valves directly to the GF2000 in order to save yourself some unnecessary peripherals.