I have not been able to find a driver for the PAC card, and I am not familiar with their hardware. I can however direct you to one of National Instrument’s signal conditioning solutions that based on the voltage specs that you posted I think would be a good fit for your application, It would also be helpful to know which PXI DAQ card you already have. I realize that this is an SCXI card but based on which DAQ card you have you may be able to easily integrate an SCXI system into your existing set-up
I would like some clarification on the specifications that you require. After rereading your requirements I believe I may have not fully understood exactly what you need. As I understand things now you will need to output 18-28VDC and the sensor/amplifier system will return a signal with current in the 28-30mA range. If this is incorrect please correct me with more specific requirements so that we can have a clearer picture of exactly what you will require. Also is the amplifier necessary? Or could the sensors be connected directly to a DAQ card?
Thank you for the clarification, the main hurdle is the large power requirement; I do however think that I may have a solution for you. You could use a NI PXI-4110 Triple-Output Programmable DC Power Supply which is capable of meeting the voltage and current requirements. Combined with an S-series DAQ card such as the PXI-6132 to achieve the sampling rates that you require. I hope this clears things up please post back with any further questions.