External Excitation with NI 9218

[linu95k]

I have two load cells which require the excitation voltage of 5V and NI-9218, however NI 9218 is capable of providing only 2V and 3.3V in bridge mode and 12V in Voltage mode. I am trying to provide 5V excitation voltage external Voltage externally using a power supply, however when I select the Excitation Source as external I get the following error:

Requested value of the property AI.Excit.Src is not supported. Possible Value: Internal

How can I use External Excitation source with NI-9218 to measure strain?

[GerdW]

Hi linu,

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@linu95k wrote:

I have two load cells which require the excitation voltage of 5V and NI-9218, however NI 9218 is capable of providing only 2V and 3.3V in bridge mode and 12V in Voltage mode.

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Why don't you use the 3.3V excitation?

Do your load cells really require exactly 5V?

[linu95k]

It does not require exactly 5V, but output that I am receiving is very low. The datasheet mentions recommended excitation as 5V to 10V. Can someone please explain how does changing the excitation voltage affect the output.

I have two load cells 1kN and 0.5kN each.