Справочник Пользователя для National Instruments CFP-2220

The cFP-22xx requires an external power supply that meets the 
specifications in the 

 section. The cFP-22xx filters and 

regulates the supplied power and provides power for all of the I/O modules. 
You must connect a power supply to at least one pair of V and C terminals. 
Optionally, you can connect a power supply to the other pair of V and
C terminals. The controller draws power from the power supply with the 
higher voltage. The controller has one layer of reverse-voltage protection.

In order to comply with standards and laws governing electromagnetic emissions 

and compatibility, you must install the ferrite shipped with the controller. If you decide to 
connect an optional second power supply, you must install a second, similar ferrite. You 
can order the ferrite from 

ni.com

. The ferrite is NI part number 711849-01.

Complete the following steps to connect power supplies to the controller.

1.

Install the ferrite 2–3 in. from the ends of the power wires. Wrap the 
wires around one side of the ferrite so that they pass through the ferrite 
twice, as shown in Figure 22.

Figure 22.  Wrapping the Power Wires around the Ferrite

Figure 23.  Closed Ferrite