Keysight 34980A DMM - Can I measure two test points at the same time?

[Balvinder]

Hello everyone, 

I am using Keysight 34980A with built in DMM function to get measurements. I am facing two issues as below:

1. The measurement that is returned the first time seems to be incorrect and currently in order to bypass this issue I am executing the VI twice to get the right value.

2. Is it possible for me to measure two test points at the same time using 34980A? I have two 34922A installed in it and currently I am having intermittent issue where sometimes the VI returns the right value and sometimes it does not. What I observed is, when I am using the VI to measure test point 1, the test point 2 will return bad values when I measure at the same time. Due to this I will have to wait until test point 1 measurement is completed in order for me to continue with test point 2 measurement which I feel is a waste of time. Additionally I have tried to run the VI continuously to monitor if there is an error and observed that the error happens intermittently when I measure AC and DC at the same time for the two separate test points. 

Is there a way for for me to block or stop the VI or test code when any of the test points is using the DMM function? I think this will probably solve my issue.

Hope someone could provide me with some inputs or ideas on how can I resolve the issue that I am facing right now. Thank you.

[cweeks12]

Are you trying to take the measurements at exactly the same time? I looked up the 34992A and it says it multiplexes the inputs. This means that it can only read one input at a time accurately, since it scans the channels. It also looks like it can do 100 channels/second, so theoretically you would have to wait at least 10 ms for the multiplexer to switch between measurements. That's my interpretation anyway.

You can have the VI "block" by putting a single frame flat sequence structure around any functions you want to take more time and put a Wait (ms) VI with an adequate wait time also in the flat sequence structure block.