| Ok, as I can never leave well enough alone, I took another look at this. First as soon as I took a moment I realized that the J&K thermocouple would be real easy to calibrate and convert to metric. I used a Fluke temperature calibrator with a millivolt output to simulate the TC"s. Worked like a charm. I tried to use the same calibrator to simulate the variable resistance of the VDO probes, but they are thermistors which are very non-linear, so even with the tables it was a challenge. So I brought home a Fluke 9009 dual dry block temperature calibrator. Good for -20°C up to 350°C at the same time (separate temp wells). That made it easy, fast and very accurate. However, the one that I'm worried about is the OAT as this one is also used to calculate TAS, HP, and "other readings". Now I believe I can correct the TAS by calibrating the scale factor on the airspeed in flight against the TAS on my Dynon. HP is an arbitrary number anyways based on what I think my max HP should be. I think I can tweak that factor as well to get it back to what I think it should be. And if I ever meet a Dyno I'll be sure to try to calibrate it properly. But the manual also mentions "other readings" without details. So I've put in an email to Tracy. If it turns out to be important, I can always put this one back and just ignore the OAT. (Its also on the Dynon) So if any of you metric blokes down under would like to do this, I can post all the parameters which you can input to your own EM2 and it will get you close. For very accurate calibration you would have to tweak them a bit using a temperature calibrator.
Todd Hi Andrew; I haven't spent much further time on the metric conversion. I think it wouldn't be as simple as I hoped. It was fairly straight forward to convert the fuel level to litres and most of the temp measurements should be almost as easy, but the K & J thermocouples have different raw data, that I don't believe would be easy to convert. And then some of the calculated parameters will likely be adversely affected as well. Probably not impossible, but first, I just don't have the time and second, I would probably have to be bugging Tracy a lot for info and he's busy being retired in the mountains of Colorado where he seems to be online only occasionally. I have however longed for a data-logger which the early EM2 didn't have (I have #003). With the increasing popularity of hobby microcontrollers I can get a Ardurino microcontrollers for $35 and a datalogger for it for $6, so I just asked Tracy about the possibility of harvesting data from the EM2. However for a few other reasons, I'm considering that next time someone on the list is selling an EM3 from an abandoned project, I might buy it for an upgrade. I think there was one recently but it was bought up right away.
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