NI USB-X 6343 AO channels on the same line gives the same signal

[newbieeng]

Hi all,

I have been encountering this issue for a couple of weeks. I am using the 4 AO channels of USB-X 6343 to control 4 pieces of proportional valves (Bürkert 2873). All valves are connected to the same power supply providing 24 VDC. The control is subsequential, when one valve is operating (let's say AO=1V) the others are waiting (AO1=AO2=AO3=0). There is no problem for the VI to do that (attached). However, not always but sometimes, the DAQ sends the same signal to the other channel on the same line. For example, the signal array is 1, 0, 0, 0, when the program starts, sometimes, AO1 sends the same signal instead of 0 (intended signal:[1 0 0 0] -no problem generating that array in VI-, observed signal: [1 1 0 0]). What could be the solution of this issue? Thanks in advance.

[Kevin_Price]

Can't really debug from a screenshot of code.  I note that your big cluster has distinct fields for "AO Array", "Signal AO Array", and "AO write Array".   It sure *seems* like you're creating an opportunity for confusion there.

Do some debugging where you toggle the "retain wire values" icon.  Add some code to look at the wire that's being fed to AO write and end the loop if more than 1 value is significantly greater than 0.   I bet you'll find that there's some condition where your code is causing the [1 1 0 0] to be output.

-Kevin P