DTAPlot is a simple/quick logfile viewer for DTAfast ECUs. I wrote this mainly to help perform analysis between runs at sprints & hillclimb events where time can be short.
The latest version is available as a Java 'jar' file from here. To run this download the file and save it somewhere on your computer. On Windows computers you may then be able to start the program by double clicking on it. If this does not work it probably means you don't have Java installed. To install Java go to http://java.com/en/download/index.jsp page and then try again.
The source code for anyone who wants to tweak this is available at https://github.com/westboost/DTAPlot. The original idea for this was based on MISA by Guy Hussey which does similar for Race Technology DL1 logs.
When started you should see a screen like the one below open.
To load a log file (in .DAT format) you just drag and drop it onto the window. When it loads the traces are split automatically into a number of "runs". The runs are found by looking for a fixed speed to be obtained and then working backwards in the log to find the start of the run. The runs are terminated after the car slows below another fixed speed. After the logfile has been loaded the speed trace is shown automatically for each run.
This way of processing the logs requires that the logfile contains someway to calculate speed. To date I have only tested with my own logs that contain a "L U SP" for a left undriven wheel speed sensor. If you find your logs don't load then feel free to drop me an email at the address below with a sample log and I will fix if possible.
To add or remove a trace you select the run you are interested in from the drop down and the tick/untick on the available traces. If a trace is disabled on the left hand side it means its not available from the logfile.
You can zoom into the details by selecting a region of the graph with your mouse while holding down the mouse button. The 'Reset Zoom' button resets the view to show the whole of the runs.
The 'Options' button allows you to set the trace units to match the type of logs your ECU outputs. If you don't set these then you might see problems like C temperatures being reported as F. Setting either kph or mph is more important as it impacts calculations. Changing options does not impact any logfile already loaded. The options are saved for you so typically you only need to set these once.
Most of the traces should be obvious but here are a few notes
The "Time Lag" trace is calculated by comparing a run to the best of all the other runs loaded. It displays the amount of time this run must continue until it reaches the same distance achieve on other runs at the same time. On the screenshot you can see a lag trace, showing time loses of up to 1.1 second at 28 seconds in to the run followed by a recovery to a loss of 0.8 seconds by the end of the run which in this cases finished on a straight.
The longitudinal acceleration trace is calculated from speed. It's important you have selected either KPH or MPH correctly for the acceleration number to be accurate.
Wheel slip is reported directly in the logs but only when traction control is enabled. If you want to record this without TC then turn on TC but set the conditions so that it won't become active, e.g. min RPM higher than actually possible.
The steering estimate is being calculated from the speed difference between two undriven wheel sensors. It's somewhat experimental as I don't know how much to trust it yet.
I run a separate boost pressure sensor connected to Ana1, the trace for boost is really just the Ana1 value.
Kevin Jones
14th October 2011