[jlrii]

While I know what GPIB is I am not very familar with the devices available. Are you currently controlling the solenoid valves with GPIB, if so consider allowing a separate pid controller to monitor flow and control the valve and allow GPIB to provide the setpoint via a resistor / voltage network switched by GPIB (dunno if that would offset costs). The devices I deal with are based in building automation systems so I am somewhat confined by their proprietary system as far as direct comunication with GPIB (and my knowelge) is concerned. What types of physical output are you currently capable of? Where you planning on providing a strict position for the valve or allowing flow to control it? I am assuming it needs to be controlled by flow due to the different Cv's of blocks tested.