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Would it be possible to get some specs in terms of a rate limit of the # of PIDs that can be scanned effectively in the standalone mode?
I realize that the rate may vary by the total number of PIDs, but even a ballpark number would be great.
These numbers are totally made up, but something like:
30 PIDs @ 5Hz
15 PIDs @ 20Hz
10 PIDs @ 100Hz
If something has that through their own testing, that would be awesome.
Thanks!
Depends on ECU / platform greatly. I did a breakdown of VAG / Simos 18 awhile back.
Thank you. I believe this is the thread you mean?Quote:
Originally Posted by aaronc7
That is valuable insight.
In my experience, I am logging only mode 22 parameters with no set refresh (as fast as possible) and it seems like the PIDs at the top of the list have a greater refresh rate than the ones at the bottom (by eye).
How did you get your refresh rate? Was that off of another OBDII scanner?
also depends on the PID type, for instance SAE params typically have a much slower polling rate than DMR's/MPIDs
additionally you can change the polling interval in the VCM Scanner channels display by right clicking on the pid you want to modify.
Open the .hpl in VCM scanner, export to CSV. UNCHECK interpolation. I use some basic excel formulas to "COUNT" the cells with updated values vs time to get refresh rate per PID and overall logging rate etc.Quote:
Originally Posted by brashendeavours
To get a little more into the weeds of looking at the OBD packets, Y-cable and software such as SavvyCAN. I've used both Tactrix OpenPort (J2534 device) and linux based SocketCAN (right now I have a Macchina P1).
Anyways, the big takeaway from that post was that there seems to be a bug (or undesirable effect at least) in how the scanner works. If you have 20x Mode $22 PIDs selected and 1x SAE PID selected....all logging at same the interval or max rate even... every other request will be for the SAE PID. And thus will absolutely kill the logging rate of the Mode $22 stuff.
The solution is to log about half Mode 22 and half SAE, or all Mode 22. I went to all Mode 22, but there's still a few SAE params I would love to log at a low refresh rate but I can't.
This is all made worse in standalone logging where things are generally a bit slower anyways. On Simos18, it was about 1/3 speed of VCM logging. This may have increased with newer firmware but I haven't tested since that post.
I actually just went to a different logging solution all together for now.
Sorry got a bit off topic there lol. Best option to see what's going on is export as CSV with interpolation turned off.