LJLogUD CH- for single-ended input? | LabJack

LJLogUD CH- for single-ended input?

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PKlammer's picture
LJLogUD CH- for single-ended input?

I am looking at LJLogUD and I don't see "AIN1" anywhere.

I see row 0 offers boxes for CH+ and CH-, but that implies differential input to me.

I see Ranges "LJ_rgBIP10V" but I haven't found explanation of that acronym yet.

On row 3, I have entered Scaling Equation "y=1000*(a-b)" and turned on the green "Graph?" button, but I don't see anything under "Scaled" nor on the graph. (I am trying to monitor voltage and power [Vdrop across 10 ohms], so 3rd "channel" is synthesized from two previous inputs).

What does "199" mean under CH- ???


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LabJack Support
LabJack Support's picture
See descriptions of all the

See descriptions of all the controls on the LJLogUD page:


For a single-ended reading of AIN1, go to any row and set +Ch=1 and -Ch=199.  199 means ground so it is a single-ended reading.

The Range constants are defined here:


Your 3rd row is not doing anything because you have set #Channels=2.  Even though your scaling equation is only using readings from other rows, you need #Channels=3 for that row to be active.