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E-Mag to EIS4000 Tach Reading

dtw_rv6

Well Known Member
Does anyone know the secret to reading the E-Mag tach output on a newer model EIS4000? I found a set of older instructions that mention cutting a resistor and a capacitor, but the sketch doesn't resemble my board in any way whatsoever.

EIS was previously connected to the P-Lead on my magneto and worked flawlessly. I moved the connection to the e-mag tach output, and it reads 0 at all times. I know the manual mentions a diode to go to a 5v signal, but I don't know what the EIS input requires since I would imagine the magneto output was much greater than 5v....

Don
 
Double check the wire...

I installed my pmag back in early september. I had a little different problem... the RPM was reading incorrectly on my EIS 4000. (vintage 2002) I had to change the "Tach-PPR" setting to 2 in my case. It was set to 1. I have a lycoming O360.
I did this using the computer program EICAD. I didn't have to make any modifications to my EIS to get a signal.

Before you do anything.... please double check your wiring. Sometimes we just over look... simply believe that something is so when it isn't. In a nutshell make sure your wire has connectivity from one end to the other. Then make sure it didn't get shorted to ground for some odd reason. Look at the diagram and make sure you are hooked into the right(terminal #6) portion of the plug on the PMAG.
 
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RE: EMag to EIS4000 Tach Reading

The E-mag manual says the tach output is a 12V signal and the output is 2 pulses per rev. The EIS will work fine with a 12V square wave input.

You might need to adjust the EIS "TachP/R" setting if your tach reading is off once you get it to display the tach input.

Did you removed the 27Kohm resistor that was in series between the magneto p-lead and the EIS tach input? If the resistor is still in place it could be affecting the amplitude of the tach signal.

I wasn't able to get my EIS to work with a 5V tach input. It read 0 RPM all the time. The new EIS units have a setting that changes the sensitivity of the EIS tach input so it will work with electronic ignition systems that provide a 0-5V pulse output.
 
I finally made it back to the airport and re-checked everything. I had used a tie wrap over the inline resistor for my magneto, and missed it when I re-wired for the E-mag.

Once the resistor was taken out of the circuit, it was just a matter of configuring the EIS for 2 pulses per revolution. I now have the correct RPM reading as before the ignition swap.

I like the E-mag feature that outputs tach. data regardless of whether the ignition is active or not.

Don
 
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