From what I heard OBDII is real-time, no problems with refresh rates.
Hi I would like to find out the speed limitation of the ODBII or CAN port. What is the max speed it supports and how many real time sensors can I monitor concurrently and accurately?
I read somewhere that the Subaru Select protocol is much faster and is able to provide real time statistic of many sensors at a go. Can someone shed more light on this?
Current CAN based OBD implementations will give you six PIDs (pieces of data) around every 100ms or so. There are manufacturer specific implementations that can go faster than this.
OK, from what I've found in my search is:
OBDII is for some reason or another limited to just a few readings a second. I don't have any proof to back this up, so don't ask. But it seems that everyone using the standard readers is only able to request that information that fast.
CAN is apparently significantly faster, but I wasn't really searching for the data regarding it, so never found out how much faster.
Each manufacturer seems to have their own specific way of making it faster. Subaru has its own way of talking and is really quick compared to ordinary OBDII. I don't know how many readings a second, and I am still not completely clear on how it works.
2000 Subaru OBS
Dell P3 @ 900 Mhz
7" Lilliput TS w/DigitalWW in-dash mount
80GB External HD
I am Zero Bitrate....
you can use my software (www.tari.co.za), its free and will be free forever. it also uses the subaru protocol rather than generic OBD2.
it will tell you all the parameters that the ecu can supply - they vary from ecu to ecu. the rate of transfer is quite fast but slows down the more parameters you select.
1. visit tari,
2. view it,
3. use it.