Справочник Пользователя для National Instruments NI 9474

Скачать
Страница из 31
© 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