9237 Load/Torsion Cell Excitation Voltage Issue

[Lukin]

Hi All,

I was recently given a custom load/torsion cell and asked to build a test system around it.  I have a 9237 to read the sensor but have an issue. The sensor has both a load cell and a torsion sensor built into it. There are output wires to read both independently a task easily done with the 9237.  However both the load and torsion cells pull there excitation voltage from the same pair of wires as the schematic below shows.

As I understand it the 9237 wants to independently provide excitation to each of its channels so that it outputs a value based on the actual excitation voltage to each bridge it is measuring.  With this configuration I clearly can't provide each bridge its own excitation.  So my question is what is the best way connect the excitation voltage.  Is it acceptable to tie the excitation outputs of both channels of the 9237 together before entering the sensor?

[STASHkal]

Lukin,

Since both supplys should be the same voltage and they both originate from the same card I see no reason not to tie the excitation leads together.  

Thanks for the image.  It made this post very clear:)

[Henrik_Volkers]

RTFMSpec page 11:

The NI 9237 is isolated from earth ground. However, the individual
channels are not isolated from each other. The EX+, EX–, and
T– signals are common among all channels.

The sense inputs need to connected too. I don't expect interfearence , but I would check it.

Stable (no) load condition, read single channels individually and together 😉

If you have a 6 (8 here) wire configuration , use it!   🙂