OpenPort 2.0 + Chrome logging without laptop

**mjannusch** · 08-18-2013, 04:50 PM

Anyone who is using Chrome 2.0 should already have an OpenPort 2.0 to perform flashing, so here's the easy way to datalog using the OpenPort without needing to have your laptop connected to the OpenPort and running EvoScan.

Needed:

Flashable 3/S ECU ('98, '99, "Clone", etc)
Chrome v2 flashed onto ECU
A 3000GT or Stealth
2GB or smaller MicroSD card, formatted as FAT16

How it works:
The OpenPort adapter functions as a MicroSD card reader whenever it is connected to your laptop with a USB cable. You should see the MicroSD "disk" mount as a drive letter. If it doesn't mount, and you get a warning message that the disk is not readable, you probably have to format it. Format as "FAT (default)" for best results. I've had success with FAT32 on mine as well, but the OpenPort guys say that there's a lot of additional overhead writing to FAT32, so to keep it streamlined use FAT (default).

Once you have your MicroSD card set up to work in the OpenPort adapter, you need to put a logcfg.txt file on the card that contains the connection method, baudrate, and parameters that you want logged. We use the MUT2 method of communicating with the ECU for logging. You could use OBD2, but its parameters are more limited and the rate of logging is slower.

The default baudrate for Chrome is the factory rate of 15625, so unless you specifically went in Chrome and changed it and flashed it to your ECU, you will want to leave that at 15625. For OpenPort logging, changes to baudrate don't make any difference in how fast logging works, so only change the baudrate if you want quicker EvoScan logging. The OpenPort is communicating with my ECU at 62500 baud just fine, and EvoScan gets about a 25% increase in logging rate at that baudrate. Only worry about that after you've gained some experience with logging and feel totally comfortable messing with such things.

I've attached a text file which is a sample logcfg.txt that you can use with Chrome. It has all the parameters defined that I think you would want to be able to log at some point. Many of the more extraneous parameters that you probably won't log on a regular basis have been commented out. This means that the lines for that parameter begin with a semicolon: ";". To log these additional items, or stop logging a parameter that you don't need, either remove or add the semicolon from the lines associated with that parameter.

Near the end of the file is a section labeled "logging conditions". This defines when the OpenPort logs the data to the MicroSD card. The first set of conditions have the OpenPort log any time the engine is running. The second set of conditions (which are commented out) log anytime the throttle position sensor (TPS) shows more than 75% throttle.

Some of the parameters have "sampgroup" definitions on them. Sampgroups allow you to have some parameters polled less often than others. By default, a parameter is sampled for each line of log output. Setting a parameter to "sampgroup=1" will log it every other polling period. "sampgroup=15" is the highest you can go, and is recommended for use with parameters that don't change rapidly or ones that you don't need real-time information from, but would like logged as a general reference (ie: battery voltage, fuel trims, etc.).

If you want to change the order of the parameter columns in the output file, you can change their positions in the logcfg.txt file.

If you run into issues with logging, look at the logcfg.out file on the MicroSD card - it will contain log messages from the OpenPort and generally tell you why your logging isn't working if you've messed up a parameter or something like that.

Here are the results of testing with the two different baudrate choices for those who are curious:

15625 baud:
Evoscan: 173 samples/sec
OpenPort 2.0: 10 lines/sec (140 samples/sec)

62500 baud:
Evoscan: 220 samples/sec
OpenPort 2.0: 10 lines/sec (140 samples) with 14 parameters
OpenPort 2.0: 6.66 lines/sec (153 samples) with 23 params all top priority
OpenPort 2.0: 10 lines/sec with 18 params but some in different sampgroups

**Greg E** · 08-19-2013, 07:09 AM

Thanks Matt! This was one of the things on my long list if things to do.

**Toni** · 08-19-2013, 02:00 PM

Yup one of the things I want to get running myself. Thanks for the info. I think Forest posted some info about how to do this as well.

**Jimvr4** · 08-19-2013, 02:06 PM

Awesome Matt !!

**J. Fast** · 08-19-2013, 09:54 PM

Excellent post Matt!

**mjannusch** · 08-20-2013, 01:50 AM

Once I started using this, I just had to share - and figured I'd just map up all the parameters so anybody can log anything they want. There's some older examples out there for the DSMs and Subarus that don't use the newer features like sampgroups and multi-byte parameters, so I figured I would just throw a sample config out there that uses all the new stuff and supports everything we need. Hopefully it helps! I'll try to keep it updated if there are any other new features added to the OpenPort 2.0, and for future versions of Chrome as well.

**mjannusch** · 08-20-2013, 11:01 PM

Note that as ECUFlash gets updated, there are typically updates to the OpenPort firmware as well. If a new firmware is available, it should get installed to the OpenPort when you go to Help -> Licensing in ECUFlash with the OpenPort connected to the laptop.