Power supply for NI9862 CAN module

[vincentlg]

Hello,

I’m currently using a NI 9144 Ethercat with a NI 9862 High Speed CAN module, in order to recover CAN data from a BMS.

I use a CAN power cable with power terminals. I have welded the DB9 to recover CAN-L/CAN-H data.

Now here is my question :

I can see in the CAN module datasheet it’s necessary to use an external power supply to the NI 9881 Vsup Pin.

Considering I’m using a 9144 chassis, am I really forced to use an additional supply?

And if it’s the case, should I have to connect the Vsup pin to the supply (by welding) or can I just use the power terminal (+/-) which are on the cable ?

Thank you

[Miro_T]

Not sure If I understand your question correctly, but the bottom line is that your should always power NI-9862 module regardless of chassis you are using it with. Take a look at the page 6 and beyond of the NI-9862 user manual.

http://www.ni.com/pdf/manuals/373243c.pdf#page=6

In general, for succesfull CAN communication with NI-9862 you will need to connect 4 wires

CAN_H

CAN_L

Vsup

COM

Depending on your network you might need termination resistors as well. Again everything is described on page 6+

[vincentlg]

Ok i understand it's necessary to power the module regardless of the chassis. But i got a CAN power cable which i enclose you a description. I wonder if the positive/negative terminal of this cable served to power the CAN (maybe they are linked to Vsup/COM pin) or whatelse ?

[Miro_T · Accepted solution]

That is correct, those two terminals are used to power a CAN bus. (Vsup and COM/GND)