Tach. sender?

[cRay Doerr(Guest)]

I have both L & R P-Leads from my Mag's connected to the EMS using the supplies resistors. I've noticed that while doing a Mag check at 2000 RPM, When I switch from Both to Left the RPM drops to 0 and then a second later shows the RPM reading. It does this same thing when going from Both to Right. If would be much easier to read if it didn't jump to 0 during this test. Also my RPM reading on the Dynon is jumping around alot while using Takeoff power. It will read 2700 then 3100, then 2800 etc. This is on a 6 Cyl Lycoming with the Pulse per Rev set to 1.5. By any chance are the RPM calulation being done to many times a second (like 60 times a secoond) that would cause it to read one pulse count during one sample and a different pulse cound during another and than when it factors in the 1.5 pulse/sec that it causes the reading to bounce all over the place. The way it is right now, it makes it impossible for me to set the Prop for 2700 RPM for Takeoff using the prop govenern set screws because I don't have a stable RPM reading.

Thanks for all your awesome support via this forum.

Ray Doerr
N519RV (just finished flying off the hours on my RV-10)

 

[dynonsupport]

Ray,
We measure the time between pulses, not the number of pulses per second, so it's not possible to miss one. We have people with 1 PPR at higher RPM's with no problems.

Your case sounds like it always reads high, which would mean it's receiving too many pulses. The first thing we'd suggest is to try a larger resistor. The exact value doesn't matter- you could try 50-100K ohms. This might dampen out any secondary pulses your system is seeing.

The mag check drop to 0 is normal. We only read one input at a time. When one drops to zero, we switch to see if the other one is alive. This can take 1/2 second. Most people don't notice it, but unfortunatley we can't get rid of it. Other engine monitors get around this by only supporting one mag input and forcing you to buy a tach sender or hook up a switch

 

[longezo320]

Dynon,  Do you have the tach set up for different pulses per rev for each input yet?


Thanks,

Sam Chambers
Long-EZ N775AM

Is this included in the latest upgrade just announced?

Thanks,
Sam Chambers
Long-EZ N775AM

 

[dynonsupport]

Yes, the next firmware release will have seperate L/R tach pulse settings.

 

[longezo320]

Yes, the next firmware release will have seperate L/R tach pulse settings.

So that feature is not in the release just anounced?

Thanks,

Sam Chambers
Long-EZ N775AM

 

[dynonsupport]

Matters what you mean by "announced." We released a version of software a few months ago. It is not in that version. We are about to release another update in a few days. It will be in that version.

 

[longezo320]

Matters what you mean by "announced." We released a version of software a few months ago. It is not in that version. We are about to release another update in a few days. It will be in that version.

;D Great!!

Thanks,

Sam Chambers
Long-EZ N775AM