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EIS and Mag Drop

S

shiney

Well Known Member
I once read a thread but cannot find it where someone was recommending a piece of kit from Aircraft spruce that would allow a reading of both mag drops by the EIS4000. I'm not sure but I think it was connected to the tach drive but can't really remember, if anyone knows of this thread can you post it here please ?


Thanks :)
 
Vans sells a tachometer transducer. It screws in where the tach cable goes and has, I think, 3 wires. +12V, ground and signal. Hook those up and the EIS will know the RPMs regardless of mags being on or off.

http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1254750905-52-132&browse=ei&product=vans-tach

IE VTACHGEN 2 or 12 depending on if you have a vacuum pump or not. A/C Spruce might have a similar unit.

The other way is to use a toggle switch SPDT and two resistors and leads going to the ignition switch so that when you do the runup you just throw the toggle switch so the tach signal comes from the correct (running) mag. This setup is shown in the EIS literature.
 
just did this

I just talked to GRT about this last week, because I had a wiring diagram that showed 1 tach input but a config guide that said there were 2. Turns out their latest version of EIS software will allow for 2 tach inputs directly to the EIS. Cost is $100 for the software upgrade. Call Sandy at GRT. You'll have to send your unit back to them.

I can't attest to how it works, because I don't even have mine back yet and I'm not flying yet anyway.

Thanks,
 
EIS 4000 - To see both the Left and Right Mag Inputs you simply wire both inputs to 1 Single pole, double throw switch and the output to the EIS.

Then switching 1 way displays the left mag and the other way displays the right mag.
 
Another method

I read a post on the Matronics RV-List this morning that said that Rocky Mountain suggests using capacitors on the two p-lead signal lines to eliminate the switch. I went to their website (found the link on VAF!) and checked the latest documentation and found the information on pages 12 and 13. They even show how to hook things up when using one mag and one electronic ignition or two electronic ignitions.

Using a capacitor makes sense. The ignition pulse would be passed to the EIS (of whatever brand) yet prevent a short to ground, shutting off the mag(s) if the wire downstream of the capacitor ended up frayed and against the airframe.

They suggest using a .01uf 400 volt capacitor.

Any comments from the electro-wizzie types out there? My thanks to Rocky Mountain for the tip and for advertising on VAF.
 
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