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View Full Version : Dynon D180 RPM feed from LASAR ignition?


Neil Moffat
04-23-2010, 01:07 AM
Posted this in glass cockpit section, but no replies so maybe this is a better section for my question.

I have just bought a FlightDEK-D180 and need to know how to get a tachometer reading from the pulses emitted from the LASAR system fitted to my IO-360.

The Dynon book says that at least 10V above ground is required, but the LASAR installation states the pulses are 4.5V minimum - Dynon say this will not be sufficient for the D180 to work correctly but they do not have any solution.

Anyone on here know what I can do?

Is it also true that when checking the magneto drop before flight that using the LASAR for output will result in no RPM indication?

Many thanks

gator
04-23-2010, 07:33 PM
I had the same problem when using LASAR system and a Dynon 120. Solved it by ordering a Tach Transducer 'IE VTACHGEN 2' on page 28 of Van's 2009 catalog and installing on my IO-360 (be carefull in installing because the length of the drive shaft on the transducer may be too long and may need to be shortened or it will pop the back plate off of the transducer?).
In doing the mag check with the LASAR system, the controller automatically shuts down the electronic ignition and swithes to the mags for the mag check when you turn the key off of 'both'. once you turn the key back to 'both' it swithes back to electronic automatically after a 20 second delay.
Hope this helps

tomagin
04-24-2010, 05:27 PM
I had exactly the same issue and solved it the same way.

The D-180 needs to be set for 4 pulses per revolution to give the right reading.

50 hours and has worked perfectly. So has the LASAR ignition.

Neil Moffat
04-30-2010, 04:01 PM
Many thanks for the replies.

Could you explain exactly how to connect the VTACHGEN 2 to the Dynon - is it just one wire to the appropriate input?

Also is it possible to take a second wire from the same source to drive the Vans tachometer as well?

The full story is that I am fitting the D180 because the Blue Mountain twin EFIS system previously fitted failed, and could not be fixed. My RV-8 was then unflyable because it had no backup engine instruments.

I'm trying to prevent that happening again and that is why I want the backup "steam" guage.

gator
04-30-2010, 07:54 PM
As I remember the VTACHGEN has two leads, one goes to a power source with an in-line fuse and the other goes to the appropiate Dynon lead.
Sorry but I can't tell you about also wiring to a Van's Tach although I believe the VTACHGEN is what is normally used to feed a Van's Tach? Maybe an inquiry to Van's Tech support would answer your question......

jay.pearlman
04-30-2010, 08:23 PM
I talked with Jason at Aerotronics who has provided really good support and he suggested the Vans tach sender. The other alternative is to pick a signal off the mag with an inline resistor. The trouble is that when a check is done with the electronic ignition only, there is no rpm measurement.

gator
04-30-2010, 10:47 PM
Jason is the one who helped me through my problem when I ran into it. The VTACHGEN is the Vans Tach Sender that Jason recommends.
Looks like we are all thinking the same way......

Neil Moffat
05-01-2010, 02:43 AM
Thanks guys - I'm going to try the VTACHGEN 2 today with the Dynon, which I am sure will be OK after your advice, and I will also try the steam Vans guage at the same time. I will let you know what happens.

I spoke to Joe Logie at LASAR last night and he said there is a small chance I could damage the LASAR system if I use the 4.5V from the tan lead on the LASAR and multiply the voltage to 10V so the Dynon will read it. Therefore I do not intend to go down that route anymore.

I suppose I am being a bit cautious installing the extra guage, but I really do not want to be in this situation (where I cannot fly) again.

Neil Moffat
05-01-2010, 08:38 AM
A partly successful day!

The VTACHGEN 2 works fine with the D180 now so thanks everyone, but the Vans supplied guage seems to have a fault and it will not work with the VTACHGEN at all - either with or without the D180.

I think the guage must be faulty and so I will try to get Vans to send a replacement one.

I'll post the result when I next have the opportunity to work on the RV-8 which will not be until 10th May, because I have to go abroad until then.

Neil Moffat
05-09-2010, 03:04 PM
I've finally got it sorted!

Received my new guage from Vans yesterday and fitted it today. I connected the white sender wire from the VTACHGEN 2 to the guage and also via the white/green wire to the D-180. Both indicators work so no more problems.

Many thanks for helping folks