Freematics Forum

Hi,

I recently purchased the Telematics Kit #3 with the I2C OBD-II adapter.

The kit itself is working perfectly, and I've already been hard at work developing an Arduino program to read, process, and display some OBD data. The problem (if you can really call it that) I'm having is that I'd like for the data I'm getting from the ECU to refresh more quickly, and I'm not sure if that's possible, or how to possibly go about doing that.

I've reduced the number of PIDs I'm pulling from the ECU to just the bare minimum of what my program needs in order to function, with the idea that pulling fewer PIDs would result in a faster response time from the ECU, but the data refresh is still pretty slow. From what I can see, it looks like the data I'm getting from the ECU via the OBD-II port is being refreshed maybe once or twice per second, which technically works, but I'd really like to see a faster refresh rate if possible- something on the order of 10 times per second. This is particularly important for fast-changing data values, like engine RPM and vehicle speed, which my program uses for several calculations.

Is there anything I might be able to do to increase the refresh rate of the data from the ECU, or am I just out of luck?

Hello, sorry i cannot help you, but I am thinking about buying one, and I want to do fast calculation for racetrack data logging. If i cannot get a refresh rate under 2Hz it is a big downside. Is it really not possible to have a higher refresh rate than 2 Hz (for OBD data) ?
Can someone reply to this question please (Stanley) ? If so, I would gladly buy one.

cheers

From our test on a newer VW Golf car, the polling time for one OBD-II PIDs is about 10-15ms. That means you can fetch 60-100 times regardless any other overhead (like drawing on screen). The OBD-II reading speed highly depends on car's ECU's responsiveness. On a older VW Polo which uses KWP2000 slow protocol), one reading takes up to 500ms.