Dynon EMS10 and LASAR Ignition

Hi,
The Dynon manual calls for 33K resistors in line on the P-leads in order to get a tacho reading to the Dynon.
The question is if one needs these resistors in line if connected to the P-leads of the LASAR.

Have asked Dynon and they do not know and told me that the EMS needs 10-50 volt on those lines.

Thanks.

Hi All,
I return to this thread to find 83 views and no replies. I thought someone out there will know the answer?
Please do not let us down here in dark Africa

I ran across this post in the Dynon news group dated Sep. 27, 2007:

The voltage on the pulses that come off the Lasar systems aren't high enough to drive our tach input. We'll have a small converter board out at some point, but we don't have a firm schedule for its availability.

Also note that you can use the Vans tach transducer (part number IE VTACHGEN ) which screws into the tach drive as an alternative. See this post for more information.

See URL http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1190915275/3 Sounds like there may be some alternative solutions.

I don't have a LASER ignition but hope this information helps.

Thanks Joe,
This is the second RV I am building and as far as I remember we have connected the Lasar P-leads ( also going to the ignition switch P-leads ) directly to the Dynon EMS. I did follow the link you have supplied but it did not help me with an answer. Note that I want to connect the two P-lead connections of the Dynon EMS directly to the Lasar P-leads and not the Lasar Tach signal.

I am installing a Flight-Dek 180 and have the LASAR ignition. Based on everything I have read on this and other sites have ordered the tach transducer from Vans and will use that "independent" signal. When the LASAR fails I'll still know the RPM!! There are two versions of the tach transducer. One if you have something on the vacuum pump pad and one if you don't. I'm going to have the 20 amp alternator from B&C so I have ordered the one with what amounts to a cable extension to get the transducer out of the way.

Regarding the resisters --- the answer for sure is that they should not be there if trying to use the signal from the tach signal from the LASAR. I saw nothing in the LASAR instructions about using the P-lead as a tach pickup. I would assume that is a high voltage signal and would use the resisters but from what I read they don't recommend this option.

Thanks guys!
I will use the p-leads and resistors and let you know the outcome.
If this does not work, I will order Van's transducer.

Do you have the Laser manual??? I can send you a PDF of it, if needed. However it is an older one, and may not be correct for your unit.

It shows the tach signal comming from a dedicated lead. Brown.

"P" leads are not the same as in a typical mag setup------I dont think they will drive the tach.

You could also contact Mahlon, who also keeps an eye on these forums.

Good luck.

Thanks Mike - I do have the latest manual.

I have the same setup although not finished yet. The tach lead on the LASAR is the brown wire and puts out 4.5 volts. According to Dynon that's not enough power but I have heard of at least one person using that 4.5 volt lead and having good results. There is no need for the resister when using either the the LASAR output or the tranducer Van sells.

Vans transducer

So this is the transducer Vans sells, although the threaded hardware connectors are removed since the system wasn't compatible with my oil filter setup. I'm using a bracket mounted on the firewall to hold the transducer in place and a cable run to it. The nut doesn't come with the transducer in the form that I bought so the one shown here is home made.




Below is a image of how the brackets being mounted.