Constant current AO

[mihamm]

Hello together,

i want to output constant current with the PXI-6738 module. For example, can I output 0.5mA as shown in the screenshot. Does this work in general and if so, what is the accuracy?

[Pater_Mater_Filius]

Hello mihamm,

In general, it is possible to use the Analog Output channel to generate constant Voltage or Current.

The accuracy depends on the specification of the device and the environmental conditions. You can try setting the Minimum and Maximum Values of Channel Properties close to each other. After deploying the project you can generate the signal using a control attached to the Analog Output channel of the device.

Best Regards,

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P.S. KUDOS are the best ways to say Thank You 🙂

[mihamm]

Hi,

meanwhile i checked out to compile this Veristand project and this was not possible. The error message was: "expected value: constant voltage" 

So i think it is not possible to set a constant current as output. 

Or is there a way to overcome this problem?

[Pater_Mater_Filius]

Hello,

Basically, this error indicates that the specified task can't be done. In case of possibility, you can try generating constant current output in LabVIEW using the module and understand if it is possible in general. If you will receive some kind of error in LabVIEW it will mean that it is not possible to generate Constant Current using PXI-6738. If you will be able to generate a current output in LabVIEW then there will be a need to check the Veristand project again and try to find any mistakes.

Best

[santo_13]

6738 is a Voltage AO module, and does not support Current AO task type.

On the other hand, if you have a constant load with known resistance, sourcing a known voltage will directly translate to a known current (within instrument capability of max. 10mA).