How to get analog input current ranges using NIDAQmx library in python

[ruby@7]

Hi,

As I am working on a program using nidaqmx library in python, I need to get analog input current range values for the specified device. I have referred the NIDAQmx library and found out that there is a class "nidaqmx.system.device.Device(name,*,grpc_options=None)", where we could get the property "ai_current_rngs". It says, "It indicates pairs of current input ranges supported by this device. Each pair consists of the low value, followed by the high value.". I used this property, but I am getting an empty list.

I tried to use another property "ai_voltage_rngs" and got a list of voltage values for the specified device.

So, is there a way to get current ranges for the specific device. Any thoughts or direction will be appreciated.

[santo_13]

What DAQmx device are you trying with? did you verify if your device support inbuilt current measurement?

[ruby@7]

Hi,

Thank you for responding. Yes, I am using PXIe 4300 card 8 AI. It does support both voltage and current measurement. I am able to get voltage range values but not for the current range.

[ZYOng · Accepted solution]

The PXIe-4300 has a 10 V maximum measurement range that can be expanded to 300 V when using a TB-4300B. The PXIe-4300 can
be used to measure current when using a TB-4300C, which provides 50 Ω resistors between the AI+ and AI- terminals to convert current to voltage for current measurements.

Reference: NI PXIe-4300 User Manual

PXIe-4300 itself does not support current measurement hence it does not return the input current range.

[santo_13 · Accepted solution]

ZYOng gave you the answer.

To be clear, your driver will return the current ranges if the DAQ has internal current sense resistors. Try connecting the accessory to the card, check in NI MAX if the accessory is detected & configured, may be, the driver may return the ideal current ranges based on the accessory connected.

You can derive the current ranges (for 4300 w/ TB 4300C) from the supported voltage ranges and the sense resistor value.

[ruby@7]

Oh, got it. Thank you so much for your time.

[ruby@7]

Thank you so much for clearing the doubt.