John,

 

I use the signal from the primary Lightspeed unit to the tach line on my VM EPI 800.  Here are some notes:

 

1. Lightspeed issues 2 pulses per revolution.  Modern VM computers have a jumper to account for that option.

 

2. The pulse must be controlled by a diode and resister. I will have to go to the airport for the diagram.

 

3. If you have a dual system, you might want to use a switch to set which ignition is feeding the rpm input.

 

I know there is more info some on the LML since I did a complete report on the install back in 04 and 05.

 

Maybe someone else has better info.

 

Scott Krueger 

 

Has anyone had any experience of using a signal from the lightspeed ignition to drive the Vision Microsystems tach.

 

My 320 has a signal generator that I think is a Ford truck part that I would rather replace and do the job electronically.

 

Thanks

 

John Spry

LNC2 320