- How precise does the 5V input need to be for the PR33-49? When testing with this circuit board yesterday it seemed like small adjustments in the 5V supply (4.9V to 5.1V) had an effect on the output current. If I was sending a command to output 20ma when applying 5V, then I adjusted the input voltage to 5.1V I would find the current to go up to 21.5ma.
Is this an issue with how I had the board wired or is this an expected behavior of the board?
Also in the sample code you provide it has the full scale range as 290-1500. In your website documentation it has the full scale range as 670 - 3460. It seems to me to be the latter values. And should these values be constant for every board and installation? Say the 5V power supply varied slightly - 5.05V for one installation and 4.95V for another. Would the DAC values still be the same to get 4ma and 20ma?
Can you use the PR33-49 with an external power supply? I know there is a built in 12V power supply and I am curious if there would be any issue using this in series to an external 12V power supply?