MoTeC Global Forum

Hi,
I am connecting some non-motec modules on the M800 can bus.They will generate some traffic, exchanging data each other, and reading the data stream comming from the M800. The M800 will only receive messages comming in ADL format.
As the M800 will "see" all the messages on the bus, will its performances be impacted by messages not related to its functionallity ? i.e. are there any masks and filters used in its can controller ? Or are the filters done in software, slowing performances when traffic increase ?

Regards

Angelo

Interesting question that I would also like to hear the Motec guys response to.

The Can bus limit on the M800 is 1Mbits/s, if you dont turn it down to 500Kbit/s

In some manuals they state that you should not exceed 90% of this, which is about 900 000 Bit/s
Samples/s = transmitted channels x transmit frequency.


The Motec ADL3 manual it says that the approximate bandwidth for a VIM is measurement rate (samples/s) * 30 bits per sample

Im sure somebody at motec will be able to give a good answer on this question

Hi Angelo,

Yes good question!
The answer is, No the m800's performance will not be affected. Non defended messages in the m800 config are masked by the CAN controller so are not processed by the main CPU.
However some address ranges are used for PC comms and the like so are open and will cause CPU usage to rise. You should avoid these ranges. The ranges are 0x220 to 0x23f, 0x2C0 to 0x2CF and 0x300 to 0x30F.

Off course you will need to be weary of overloading the CAN bus also, it shouldn't affect engine running unless CAN traffic is relied on for sensor values etc.

Cheers,