National Instruments USB-9472, User Manual And Specifications

©

 National Instruments Corporation

15

NI USB-9472 User Guide and Specifications

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 USB-9472. 

If the power supply you are using with the NI USB-9472 cannot supply 
more than the guaranteed trip current, 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 though the channel is off because of an overcurrent 
condition. To determine if the channel is in an overcurrent state, measure 
the voltage between DO and V

sup

. If the voltage is equal to the voltage of 

the external power supply connected to the module, the channel is in an 
overcurrent state.

Resetting Channels After an Overcurrent Condition

After you have determined and fixed the cause of the overcurrent condition, 
reset the channel by turning it off. You can disconnect the external power 
supply from the module, however, doing so disconnects power from all of 
the module channels. Normal operation can resume after you correct the 
overcurrent condition and reset the channel.

Specifications

The following specifications are typical for the range 0 to 60 °C unless 
otherwise noted. All voltages are relative to COM unless otherwise noted.

Output Characteristics

Number of channels ............................... 8 digital output channels

Output type............................................. Sourcing

Supply voltage range (

V

sup

).................... 6 to 30 V

Output voltage

........................................ V

sup

– (

I

0

 · 

R

0

)

Output impedance (

R

0

)........................... 0.13

Ω

 max; 0.07

Ω

 typ

Continuous output current (

I

0

) ............... 0.75 A max per channel