I have been tring to bypass elvis and have my DAQ (USB-6251) write directly to the ELVIS DIO pins (I want to be able to write fastr than ELVIS alows). I an so far unsuccesful. So I thaoght I would try a digital write using the DIO writer and reader. This works fine, the DO pin can write to a DI pin and ELVIS is happy. But when I connect the DO to an LED it will not light. When I measure the voltage with the ELVIS DMM the voltage measured is only mV and not the expected 5volts. The ELVIS DI reader will see a high level DO but as soon as I connect the DMM the DO sees a low voltage level.
I just discovered that all grounds are not the same. I had been using the power supply ground for the voltage reading, use the ground on the RHS and all seems to work
