What Overcurrent Protection Does my NI 9403 Have?

Updated Jan 10, 2019

Reported In


  • NI-9403

Issue Details

Does my NI-9403 already have current protection built in, or do I need to provide external circuitry to protect the device?


Each channel has a pull-down resistor and includes overvoltage and overcurrent protection. The overcurrent protection allows only a specified amount of current through the output channels. If the channels go into an overcurrent state, the NI 9403 tri-states all the DIO channels for approximately 280 milliseconds. When the channels are in this state, the NI 9403 can accept new line direction configuration and output state data but cannot pass valid input data to the software. 

After the channels return to a normal state, the NI 9403 automatically recovers to the latest direction configuration and output state. If the overcurrent condition still exists, the module again tri-states the channels. This cycle continues until the overcurrent condition is removed or the current returns to an acceptably low level. Typically, shorting 1 output to ground will not cause an overcurrent condition to occur but will increase the likelihood that it will trip the NI 9403 overcurrent protection circuit.

Additional Information

There is no way to programmatically know if the overcurrent protection is currently active or not.