Power supply from CAN hardware PCI board

[pegoraro]

I am using a PCI-CAN/2 board to construct a network among some equipments. I need know how to get the power supply ( 5v ) from the two ports of that board to a circuit which contains a PCA82c250 can controller from phillips. I have already tried switch the board's jumpers to internal power mode and external power mode but no voltage was appeared. How can I do this ????

[Randy Solomonson]

Yes, this can be quite confusing. The internally/externally powered option refers to how the transceiver of the NI-CAN board is powered. When internal, the transceiver gets its power from the computer. When external, the transceiver gets its power from the V+ line of the CAN bus. Changing to external power will NOT bring any power to the V+ line.

If a CAN bus requires power, try adding a power supply that can produce the recommended voltage. In such a case it is best to either set the NI-CAN board to externally powered or do not connect the V+ line to the board.

Randy Solomonson
Application Engineer
National Instruments