National Instruments NI 9472 - Manual (Page 15)

© National Instruments Corp. 15 NI 9472/9474
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.
Power Supplies and Overcurrent Conditions
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