Maximum Output Current

The maximum output current rating of the NI-9470 is limited by the total module dissipation rating. No single channel's peak current can exceed 3.5 A. Refer to the Maximum Current Per Channel table in the Output Characteristics section of the NI-9470 Specifications for more information on several permissible load current cases.

For applications not covered in the table mentioned above, use the following formula to determine whether the total module current of your loads for active channels is within the specification. The total percentage must remain under 100%.

Figure 1. Total Module Current Equation
P e r c e n t U s a g e = 4.3 % * ( I . c h 0 2 + I . c h 1 2 + ... + I . c h 7 2 ) P e r c e n t U s a g e = 4.3 % * ( I . c h 0 2 + I . c h 1 2 + ... + I . c h 7 2 )

For example, an NI-9470 with two channels at 500 mA, two channels at 1 A, and four channels at 2 A is within the maximum current rating. See the following calculation.

Figure 2. Example Calculation
4.3 % * ( 2 * 0.5 2 + 2 * 1 2 + 4 * 2 2 ) = 79.6 % 4.3 % * ( 2 * 0.5 2 + 2 * 1 2 + 4 * 2 2 ) = 79.6 %