Lightspeed EI tach settings?

rickw

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I am getting high tach readings when running on my mag and lightspeed. If I switch to just mag, its accurtate. Dynon manaul talks of adjusting the pulses per rev. With Dynon and Lightspeed closed for the weekend...anyone know the proper pulses per rev for a lightspeed 2 plasma so the tach on the skyview gets the info properly?? THANKS
 

Nrgtech

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Apr 12, 2011
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I'm having the same RPM doubling issue with my IO-360 (one mag/one Lightspeed). When checking just the mag the rpm is correct... but the Lightspeed reads double when isolated or "both" are selected.

What's the answer for this issue?

Nrgtech
 

dynonsupport

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As the manual says, you need to set the pulses per revolution correctly for the ignition systems you have installed.

If you are getting twice the RPM you expect, then you need to double the pulses per rev on the input that has the device that reads high. A mechanical mag and a lighspeed don't generally put out the same pulses per rev, which is why we allow different settings for the left and right inputs.

I don't know the correct lightspeed number off the top of my head, but it's easy to adjust and if you have a mag that is reading correct you can just keep making it higher until it matches.
 

rickw

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To dynon as a suggestion... "as per the manual says" is not very helpful. To some of us the wiring, electrical, panel stuff is very difficult. I have read the manual, and every revision since it was started. BUT...guessing at PULSES per rev isnt something I am comfortable doing. I asked lightspeed and I asked you...everyone kind of blows it off as its in the manual. Selling stuff to experimental/homebuilders sometimes requires you to answer questions that might be hit on the manual but....we need a little clarification. Timing, pulses...add resistors as required...that kind of answer isnt enough for people who arent experience at this. I did find another builder who was helpful, and gave me the info to raise the pulses on the lightspeed side by 1. That is all I needed and its NOT clear in the manual. Will see when I put more hours on if that was the correct fix.
 

cs-xce

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I have a left mag and a right LSE plasma II plus. When I check the left mag the RPM reading is normal, showing 70 RPM drop. When I select R mag (CDI) I get 0 rpm, no information rpm at all.
I use the pin 35 (green) Low voltage input for LSE CDI on Right and the pin 32 to the magneto on left (10+volts). this is correct?
 

dynonsupport

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Rick - we try to provide authoritative information configuration when we're positive about it, but we will sometimes omit such information when we can't easily find a clear documented source. For the lighspeeds, from past customer feedback on the forum, it looks like 2 pulses/rev is the answer per http://www.lightspeedengineering.com/Manuals/InputDiagram.htm. Lightspeed may be able to provide a more authoritative answer here though.

Antonio - So first, let's make sure that we're talking about the same thing. Which ignition device is providing the spark when you are getting a valid reading? I think you're saying that you select the R side, which shuts off the conventional magneto, you don't get an RPM reading from the LSE, which is providing the spark. If this is the case - what wire are you going to on the LSE? You should be going to the pulsed output, which is pin 6 on the input connector. See http://www.lightspeedengineering.com/Manuals/InputDiagram.htm
 

cs-xce

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for the tach input into the SV EMS 220 we used the PIN 35 for LSE (R) and PIN 32 for MAG (L) on EMS.

When running only on LSE (R) no RPM information on SV
 

dynonsupport

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So pin 35 is the low voltage inputs, so that should be able to measure the square wave from the Lightspeed input connector. Is that wire you're using? Also, make sure you're NOT using an inline resistor on the Lightspeed - that would chop the voltage too low.
 

cs-xce

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I did not built the airplane, I contacted the builder and he wrote;

The Dynon has two sets of wires that monitor the RPM. One is for high voltage - mags and the other is for low voltage - electronic. I used the high voltage lead with a dropping resistor for the left mag. I then used the low voltage lead without a dropping resistor for the right electronic mag. Check with Dynon to make sure this is correct.  Your electronic mag supplier, LSE Plasma II+, should be able to tell you how to wire and set up the Dynon to work with their unit. If not, they should be working directly with Dynon to resolve the issue.

I did asked to the LSE people about the same issue and they wrote;

The tack pulse of the Plasma II is only 0.3mS long, check with Dynon to see if they can read that.
 

dynonsupport

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In our first generation of products, some people had success, and some didn't, reading that pulse length (we suspect there is some variation on that output). SkyView should be a bit better here - but it might not be quite enough. If it's not working, though, you might try hooking it up to the high voltage input as an experiment (also without a resistor). You also might check that the right wire from the lightspeed's input connector is actually hooked up to the right wire on the EMS, and that it's continuous all the way to the connector.

Finally, if there's no joy, you won't have RPM when you shut the mag off. Some people use the Vans active tach transducer, which has a 12V pulse that never goes away (as long as it's getting power).
 

cs-xce

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Today dynon read 33000 rpms on both screens!!!! the engine was running around 1000 but the reading was absurd! what is the problem?
when isolated only the CDI red 0 rpm as always and when isolated the mag only or both the rpm were above 33000!!! was the first time I saw this happen.
Any help?
 

dynonsupport

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Something is sending the RPM inputs a very high frequency that SkyView is interpreting as a very high RPM signal. Since you're having continued issues, you might consider using the Vans tach transducer instead of the connections you currently have.
 

cs-xce

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This happen only yesterday. The system have given the correct rpm's since January. Something changed yesterday!!!
 

dynonsupport

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Did this happen immediately after upgrading to software version 3.2? Anything at all change in the airplane, even if not something connected to SkyView?
 

cs-xce

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I had problems in configuration before when I for mistake upload one wrong file. After that I correct all the parameters of the EMS like FF, MAP, OIL Temp, etc.
Since many months ago the values was correct. 3 days ago I flown the aircraft and everything OK. Monday happen this, the RPM's abnormal reading. Nobody touched the airplane between sunday and monday.
sunday was OK monday not. today I recheked the EMS settings and looks everything fine, I start the engine and again readings above 30.000
 
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