CAN Message Priority
"jtolmanserra" <[email protected]>
| Newsgroups | gmane.comp.hardware.bus.can |
|---|---|
| Message-ID | <[email protected]> |
Hi, I am new to CAN and am working on a project that has 40 identical nodes and a master. Each node is a motor that has two encoders. The two encoder values, each 32-bits, will be transmitted in PDO #1. PDO #1 is configured in each node to transmit acyclically with an inhibit time of 50ms. Network speed is 125K. I know that the network speed will have to be bumped up, probably to 250K or even 500K. My understanding is that it is the COB Id that determines the message's priority for getting onto the network. I am currently using default COB Ids (PDO #1 is 180h + Node #). It then makes me think that the lower the node number, the higher the priority, correct? So one of my concerns is that with 40 nodes all sending their PDO #1s every 50ms, is it possible for the higher nodes to NEVER get to send their PDO? If so, then how can I get around this? Should I use the SYNC method? And isn't that going to slow things down a bit? I'm just trying to understand the limitations of CAN and what the best method is for a system of 40 slave nodes. Thanks. I appreciate all answers or suggestions! Jeff -- Archives and useful links: http://groups.yahoo.com/group/CANbus Subscribe and unsubscribe at www.vector.com/canlist/ Report any problems to <[email protected]>