Multiple PXI-8512 CAN cards in RT PXIe chassis switching port identifiers

[toddy]

I have several PXIe chassis with RT controllers and PXI-8512 CAN cards. In the chassis that have multiple CAN cards, sometimes the left-most card's CAN ports are CAN1 and CAN2 and the right-most card's ports are CAN3 and CAN4. Other times when it boots up it switches these around, so the right-most card's ports are CAN1 and CAN2. This is incredibly frustrating!

These systems are running stable RT executables, it's just that the OS seems to randomly assign the port identifiers.

Now I could identify the ports by serial numbers or something like that, but I run the same code on many controllers, so that doesn't work for me either. Is this a bug?

[ZYOng]

I have never seen something like this. It is strange.

What's the model of your PXI controller? What's the OS? What's your NI-XNET version?

I don't remember but can you change the CAN number in NI MAX? If it is possible, then we can update it programmatically using NI System Configuration API.

[toddy]

Controller is a PXIe-8135 running Labview RT (Pharlap)

XNET 21.5.0

It does seem like it would be possible to re-name them from a drop-down box in MAX, although I've never actually done it.

I'll look into the NI System Configuration API, I've not used that before

Thanks

[toddy]

Not having much luck with the system configuration vis.

Tried this out on a system with just 1 PXI-8512 card and it doesn't seem to report anything very useful!

[ZYOng · Accepted solution]

I was not able to locate the property in NI SysCfg API. It is a read-only property in NI-XNET.

However, I figured out that you can use the slot number to get the port number instead.