National Instruments NI 9472, NI 9474 Detecting an Overcurrent Condition

more information about the maximum continuous output current,

short-circuit behavior, and short-circuit trip time. You also can

refer to the IEC 1131-2 standard for more information about

short-circuit-proof devices.

Tip Because the NI 9472/9474 module includes internal

flyback diodes, you do not need to add external diodes

when connecting to switching energy storing devices.

If a short-circuit occurs, the current through DO can exceed the

current rating for the power supply and the maximum continuous

output current for the NI 9472/9474.

If the power supply you are using with the NI 9472/9474 cannot

supply more than 13 A, the module may be damaged if a

short-circuit condition occurs.

Detecting an Overcurrent Condition

If a device connected to the module is not working while the

channel is on, the module channel may be in an overcurrent state.

Neither the software nor the module LEDs indicate if an

overcurrent condition occurs. A channel LED may be on even if the

channel is off because of an overcurrent condition. To determine if