How Does the NI-DAQmx Overcurrent Detection Work?

Updated Mar 13, 2024

Reported In

Driver

  • NI-DAQmx

Issue Details

What is the expected behavior of the overcurrent protection properties? Should I expect an error or reset the device after the overcurrent condition? 

Solution

Here you can find help documentation about the overcurrent detection features: As mentioned in the documentation, notice the Overcurrent Channels Exist property should be called first and then the Overcurrent Channels Property.

The overcurrent condition and the hardware behavior will depend on the module used. You can consult your module's datasheet and manual for more information about this.

For example, the NI-9269 (Analog Output module) supports sourcing +-10mA per channel typical and +-20mA all channels maximum, according to the NI-9269 Specifications, so this is how the Overcurrent detection will work:
  • Requesting 11 mA or more in a channel causes the Overcurrent Channels Exist to return True and the Analog Output channel name is populated in the list as an output of the Overcurrent Channels property
  • Reducing the output voltage and for instance the current below 10mA, will make the Overcurrent Channels Exist to return False and Overcurrent Channels Property return an empty list. 
  • This happens while the Analog Output VI is running. For instance, there’s no reset or action you need to take to reset the property or the device. If the current drops back into the working range, we’re back to normal operation.