Hi, I am using a PCI 6030E multifunction DAQ board for a multitude of purposes in my current application. Most of it works perfectly, but I am controlling several power supplies using this board through the AO voltage. This works fine, but the PS's supply a 0-10 V output indicator of the voltage that is being produced (0-100% of the total output, in this case 30 kV). When I measure this voltage with a multimeter, the voltage is exactly right (I see 1.66 V for a 5 volt output), but when I use the AI voltage functions, I get much lower values which decrease with time. I believe this is a current problem, the PS indicator uses a 10 kohm resistor to protect the circuitry from errant voltages applied to this channel, so I have a maximum of 1 mA. If I sample at a lower rate (1-2 Hz), the values rise closer to that which I would expect, but due to the timing of the system, I cannot go any slower than this. I believe the DAQ system is simply drawing too much current and so a voltage drop is seen, but do not know how to correct this problem. Any suggestions? Below is a screenshot of the code I am using to view these voltages.<>< Eric

LabVIEW

analog in voltage draws too much current

Author

Thank you for the warning....my point when I said I dont have experience in electronics was about creating circuits of the type we were discussing. I have a lot of experience working with the HV supply, and commonly create instrumentation which uses such a supply. I do appreciate the warning, however.

<>< Eric