How do I use multiple messages with CAN CREATE MESSAGE?

Question

I'm an old hand at DAQ, but new to CAN.
I need to configure the CAN interface without using MAX or a DBC file directly (because i want the user to configure EVERYTHING in one place, and MAX doesn't handle my other channels).
I can provide the message IDs, channel start bits, etc., etc., by importing a DBC file myself.
So I'm looking at the CAN CREATE MESSAGE vi. I can make it work, using a single message, and a few channels on that message.
But how do I add another message to that task? Or do I create another task to handle a different message?
What's the difference between CAN CREATE MESSAGE and CAN CREATE MESSAGEex? I can't find any in the help docs.
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
Culverson.com
Blog for (mostly LabVIEW) programmers: Tips And Tricks

Answer 1

you can’t programmatically add messages/channels to an already existing task
So I can't create a task with more than one message, and I can't add a message to an existing task.
That sounds like I have to have a separate task for each message I want. That means separate READ operations at DAQ time. I hope the overhead doesn't cost too much (I'm doing a thousand other things at DAQ time).
I have an RT card in the system I'm designing. It's only using about 5% of the CPU time (PID controlling an engine). Will NI-CAN stuff work on the RT? How do I physically connect it? Is CAN just RS-232 at fast baud rates, or are there more electrical differences?
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
Culverson.com
Blog for (mostly LabVIEW) programmers: Tips And Tricks