Read and write to/from multiple identical CAN-devices

[Christ0phe]

Hello,

I am very familiar with Labview but not so much with CAN. The only experience that I had was to connect to a USB/Kvaser interface to an ECU and to poll the data from it using Kvaser Labview library. It worked well. The challenge that I have got now is to connect to 12 identical ECU and to poll and control them simultaneously. There is no possibility to change their ID hence I guess no possibility to build a single CAN-bus and to end with a single USB convertor to the PC. I envision two possibility and maybe none are convenient:

1/ buy 12 Can-USB convertors and use a 12 ports USB hub to connect them to the PC so that they are treated individually. (or use 6 NI-CAN boards)

2/ buy some sort of intelligent (?) device that I do not know that would be between the ECU and my PC. This intermediate device would accept 12 devices connected and can be programmed maybe to change their ID so that for the PC the different devices will have a different 'virtual' ID. It has to work in both direction ie. the PC must be able to control each of the 12 devices and also receive information from them.

Of course a solution like 2/ looks nicer than 1/ but I will wait for your proposals before taking my decision... 

Thanks for any hint, that will be very useful.

Christophe

[O_Proulx]

Hey Christophe,

You can look into using one of our switch modules like this one to connect CAN_H and CAN_L from each of your modules to the CAN_H and CAN_L lines on the NI-CAN port.  You would need to program the switch module to change the connections, but it would require less hardware.  The easiest "programming" would be using 6 two port NI-CAN cards.

Let me know if this helps.

[Christ0phe]

Hello,

We are not using PXI and 6 PCI slots in a PC is all but standard.

Any other ideas? Does someone know hardware from CAN-bus specialists that could do the trick?
Thanks,
Christophe

[sammy346]

I can't say for certain, but I have reservations about the switch idea!

The can bus signals (high and low) are sitting at certain voltage levels... what happens when you switch in/out the relays, what if they bounce. 

If it is a test system, wouldn't you be wanting to simulate a real-world scenario which... in a vehicle - everything is wired onto the bus permanently.