| s1900ahon |
05-07-2009 02:18 |
Re: pic: cRIO CAN Jag
Quote:
Originally Posted by biojae
(Post 865715)
It looks like it could be made easily, how much does NI sell it for? (We will probably get one in the kit though)
Also what module # is in the cRIO?
I know that the jags can do 1mb per second comms, and there is a 1mb module but there is the possibility of us having the slower comms, (Though i don't believe that we will ever need to have that much data throughput)
|
The cable pictured is not available from NI. It was a small custom build for NItro. It is a small piece of 9 conductor ribbon cable with 4 flat ribbon DB-9 connectors crimped on it. One DB-9 is used for connecting to the Jaguars, one for connecting a termination resistor, one to connect to the NI CAN module, and the final for connecting a CAN bus analyzer. The parts are cheap and no soldering required.
A comment on the bus bandwidth.. the number of packets per second you can get on CAN depends on a number of factors. If you consider a 29-bit message identifier (as used by Jaguar) and average bit stuffing, on a 1 Mb/s network, you can get >12,800 1-byte packets per second and >9,300 4-byte packets per second. I bet that some crazy team will be complaining in a year or so about the need for more CAN bandwidth :). The nice thing about CAN is that there are no collisions, so you know when it is busy the data still gets through. |
