Multifunction DAQ

Showing results for 
Search instead for 
Did you mean: 

Wiring up and displaying String Pot data


I recently inherited a LabVIEW DAQ system which was built by my predecessor long ago. 
The system was built to take data from several strain gauges, string pots, and a hydraulic actuator.
I am in the process of rebuilding the system for another project while still using strain gauges, string pots, and actuators in a different configuration.

I need help wiring the string pot and getting the displacement data to display in lab view. I could use some assistance with wiring into the BNC-2090A, setting a zero, and getting the data to display on the graph. Specifically, where to insert the black and red wires for the string pot pictured, as well as where to wire subsequent black and red wires if I want to connect several string pots at the same time. All of the string pots have the same tail end with a loose black and red wire and blue and white wires going into a BNC.

I've attached pictures of my set up. Please let me know if you need any more pictures or details. Thank you.

0 Kudos
Message 1 of 7



Can you describe what the wires are? (power, ground, signal, etc.)? Otherwise we have no way of knowing what those wires are supposed to be. 


Also, the BNC-2090A has a BCN connector type, like a coaxial cable. So if you want to connect wires to the inputs, you will need a converter, like the one the white and blue wires are using





Michael Pahl

Technical Support  Engineer

National Instruments


0 Kudos
Message 2 of 7

I just spoke with the manufacturer of the string pot. The loose red wire is my excitation voltage (5V), and my black wire is my ground.
This is the PDF guide for the model of string pot that I have.
Is it possible to wire the inputs without a converter? The red and black wires looked crimped on the end as if they were inserted directly into the screw terminal block.

Let me know if you need any more information. Thank you for the reply.

0 Kudos
Message 3 of 7

Also, when I hit record in LabView, the graph shows the voltage as not being a flat line, but rather declines slowly and steadily. Not sure if this is relevant. Thank you.

0 Kudos
Message 4 of 7

See wiring diagram attachment. Thank you.

0 Kudos
Message 5 of 7

IT'S ALIVE!!!! Pictures attached.

I got the string pot to respond to pulling on the transducer. The string pot that is active is the top connection in card number 6.
If I wanted to use 2 or 3 string pots at once, would I have to use a separate card for each, or could I use one card?
If I wanted to use one card, how should I wire them?
Thank you for your help.

Download All
0 Kudos
Message 6 of 7



so from the documents you attached, it looks like the wires go as following:
Red = power (VIN)

White = signal out (VOUT)

Black = ground (GND).

It appears blue is not internally connected (NC).


So to attach more transducers, you need to connect the red wires into +5V somewhere, maybe on the empty one below.

the black wires need to go into DGND (device ground). These two will ensure your transducer is getting power and grounded properly.


The last step is to connect the signal wire to the BNC, so you will have to connect it to another port just like you did in the first picture. This can all be done on the same card. You can has as many sensors as you do analog voltage inputs. 

Does that help?



Michael Pahl

Technical Support Engineer

0 Kudos
Message 7 of 7