Each channel of the NI-9474 has a continuous output current of 1.0 A. If you want to increase the output current to a device, you can connect any number of channels together in parallel.

For example, if you want to drive 4 A of current, connect DO0 through DO3 in parallel, as shown in the following figure. You must turn all parallel channels on and off simultaneously so that the current on any single channel cannot exceed the 1.0 A rating.

Figure 3. Increasing the Current to a Device Connected to the NI-9474