Below is my EM2 calibration data table. I hope it comes through to the list OK, otherwise I'll post a link.

The only Dynon I have is the D10A, which is just flight instruments, so other than sharing a pitot probe there is nothing common. The Dynon has it's own OAT sensor which is connected through the EDC magnetometer (electronic compass)

EM2 Calibration Data
Ch. #	Function	Scale Factor	Zero Offset	Sensor Offset	Low Limit	Hi Limit	sensor type	location
0	H2O temp	3.152	20	447		100	VDO 323 095	H2O out of engine, before cooler
1	Aux air 2	3.6	0	69			LM34DZ	behind right radiator air
2	aux LT 1	1.825	20	490			VDO ? 323 057	Oil Sump, before cooler
3	RT fuel	0.572	511	756			SW F-385C	Right Outboard tank
4	oil temp	3.219	20	445		90	VDO 323 095	Oil into engine, after cooler
5	LT fuel	0.784	511	828			SW F-385B	Left Outboard tank
6	aux air 3
7	aux LT 2	3.114	20	446			VDO 323 095	H2O into engine, after cooler
8	oil press	9.436	0	55	25	95	VDO 360 086D	Oil into engine, after cooler & filter
9	H2O press	32.211	0	88		21	VDO 360 043	Coolant swirl bottle
10	aux air 1	8.105	0	176			LM34DZ	behind left radiator air
11	OAT	8.666	0	439			LM34DZ	under right wing root
12	fuel press	13.7	0	99			VDO 360 086	fuel rail loop
13	mixture	5.119	0	0
14	air speed	10.008	0	46	45	200
15	altitude	3.598	-50	7542
16	CHT 1	0.454	0				J type TC	fuel filter/water seperator
17	CHT 2	0.454	0				J type TC	MOCAL oil inlet
18	CHT 3	0.454	0				J type TC	MOCAL H2O inlet
19	CHT 4	0.454	0				J type TC	various, currently cowl air out
20	EGT 1	1.046	0			950	K type TC	Rotor #1 exhaust
21	EGT 2	1.046	0			950	K type TC	Rotor #2 exhaust
22	EGT 3	1.046	0			950	K type TC	TIT, turbo inlet
23	EGT 4	1.046	0			500	K type TC	exhaust pipe 30" downstream of turbo
24	MAP	13.639	30.029	371
25	voltage	6.277	10	0	130	155

The temp sensor that is in the oil sump (aux LT 1,channel 2) has far different cal data as the other VDO temp sensors. I'm not sure where I got it from and it has no markings on it, but it's ohmic range matches the published data for a VDO 323 057 (max 150C), so I'm assuming that is what it is, but take that one with a measure of skepticism. It calibrated fine so I'm using it for now, but my next order from ACS will include a new VDO 323 095, to match the others.

Todd

Todd Bartrim

On Sat, Jun 23, 2018 at 4:42 AM, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:

Hi there Todd
I’d be very interested in the settings though I have an EM3 and I’m not sure of the difference between models 2 and 3.
Do you have all seperate senders for the Em2 and Dynon?

Steve Izett

> On 23 Jun 2018, at 5:33 pm, Todd Bartrim bartrim@gmail.com <flyrotary@lancaironline.net> wrote:
>
> 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
>
> On Fri, Jun 8, 2018, 00:46 Todd Bartrim bartrim@gmail.com, <flyrotary@lancaironline.net> wrote:
> 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.
>
> Todd Bartrim
>
> On Thu, Jun 7, 2018 at 7:58 PM, Andrew Martin andrew@martinag.com.au <flyrotary@lancaironline.net> wrote:
> Todd, did you ever get the EM2 recalibrated to metric? I never attemped this as doing so usually gives me quite a few hours work to get back to a working system. I used Tracy’s factory calibration in the EM2 as the base to calibrate my efis, which is in metric. It is a minor inconvienience to do the mental arithmetric when comparing instruments, but would be interesting to know if you succeeded.
> --
> Regards Andrew Martin Martin Ag
>

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