temperature, the switching frequency, and the amount of current
switched by other channels within the same module at the same
time.
NI recommends using 2 meters of cable for safe operating
conditions. Higher currents, higher frequencies, and longer cables
contribute to increased heat in the NI 9478. Refer to the device
datasheet at
for safe operating conditions.
You can determine safe operating specifications for the NI 9478
by using the following equation.
Figure 5.
Safe Operating Conditions Equation
�
= 4 %
�
���
2
+ 0.12 %
�����
ℎ
−
0.2
�
���
2
+ 0.04 %
�
���
+ 1
����
where
P
is the percentage of total allowable power the channel uses
I
out
is the output current in amperes while the channel is on
length
is the total cable length in meters
freq
is the frequency rate in kHz at which the output channel
goes through an on-off cycle
NI 9478 Getting Started Guide
|
© National Instruments
|
17
