PID common short names

chunkyks · 09-21-2009, 12:55 AM

Evening all,

I've added code to obdgpslogger so that the PIDs it logs are modifiable at launchtime.
Currently it only works through a config file, or at compile time [not command-line yet]

Code:

man 5 dot-obdgpslogger

The remaining bit that I need to do is to go through obdservicecommands.h and rename db_column from NULL to a useful short column name. Things like "vss" for vehicle speed.

I wouldn't have come up with "vss" myself, but everyone else appears to be familiar with it; it seems to me that there's a common source for names of these things, but I don't know what that source might be.

Can anyone please point me in the appropriate direction for short_version nomenclature for PIDs?

Thanks,
Gary (-;

malcom2073 · 09-21-2009, 05:47 AM

VSS is actually vehicle speed sensor iirc, which is why that's used for that particular PID. Unfortunately the nomenclature comes more from the mechanics side than the OBD side, MAF, MAP, TPS, LV8 (I never understood this one), all abbreviations for the sensors the values represent.

Rooster · 09-21-2009, 01:45 PM

I am struggling with the same issue. My application uses a 128x64 graphic LCD for displaying data so there is limited space for labels.

Some tags I have been using are:
IAT - intake air temp
AMBT - ambient air temp
O2S1B1 - O2 sensor 1 bank 1
O2S2B1 - O2 sensor 2 bank 2
ADVNC - timing advance
TPS - throttle position sensor

When you make your own tags it is easy for you to know what they mean because you made them. But I wonder if anyone else will know what I mean.

An 'unofficial' standard for short tags would be nice indeed.

chunkyks · 09-21-2009, 01:54 PM

I have been informed off-forum [thanks Graham!] thus:

Quote:

The short names are just the abbreviations you see in your copy of SAE 1979
under the column External test equipment. Perfect for a db_column name.

Now if only I can find my copy of 1979, then I'll be set. I *think* that it's *somewhere* in my garage - we haven't really begun unpacking since we moved in :-(

Gary (-;

chunkyks · 09-21-2009, 11:09 PM

Yep. Garage it was.
obdservicecommands.h. Now obdgpslogger's columns-to-log are run-time configurable.

Reading my spec, I found that the spec contains info on PIDs up to hex eighty-something, but the only online references go up to about 0x52. Can anyone point me to an already-published online reference for these higher PIDs? J1979 is kind of a proprietary spec, publishing stuff from it almost verbatim [in a big struct] wouldn't be my best idea.

Gary (-;

justchat_1 · 09-21-2009, 11:21 PM

Any chance you have a copy of the spec in PDF form?

chunkyks · 09-22-2009, 12:23 AM

Sorry, I sprang for the dead tree flavor because the PDF version carries DRM burdens that will not work for me [such as requiring a separate, windows-only, proprietary plugin to view]. Then there's some limits on what you can do with it [such as number of prints, or simple things like viewing while not connected to teh intertubes].

For that matter, even if I had the PDF version, I'd be unwilling to hand it around; respect of copyright is pretty central to the whole world of open source, even if there are occasional ridiculous copyright laws.

Gary (-;

PS **** DRM. Congratulations, assholes, you managed to make the electronic version *less* useful that the dead tree flavor. It boggles my mind that that's even possible.

</tirade>

justchat_1 · 09-22-2009, 01:26 AM

Quote: Originally Posted by chunkyks

Sorry, I sprang for the dead tree flavor because the PDF version carries DRM burdens that will not work for me [such as requiring a separate, windows-only, proprietary plugin to view]. Then there's some limits on what you can do with it [such as number of prints, or simple things like viewing while not connected to teh intertubes].

For that matter, even if I had the PDF version, I'd be unwilling to hand it around; respect of copyright is pretty central to the whole world of open source, even if there are occasional ridiculous copyright laws.

Gary (-;

PS **** DRM. Congratulations, assholes, you managed to make the electronic version *less* useful that the dead tree flavor. It boggles my mind that that's even possible.

</tirade>

I was thinking more along the lines of if i had a sample or two of what was "undocumented" then it would be a lot easier to find the sources where it is documented. Along those lines anything that can be reverse engineered is fair game - as long as its not done using their specs.

Would you mind posting a PID or two (just the code) and i'll see where they're defined. That shouldn't be a problem since your not posting descriptions.

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