Lightspeed EI and Rocky Mountain Monitor

Has anyone else connected a Plasma III tach output to a Rocky Mountain Instruments Micromonitor?

I suspect it needs input inpedance tweeking (the Micromonitor), and I'll talk to the designer tomorrow hopefully. But, I was hoping to work on it tonight. I had the Lasar system previously, and I did jumper across R3 in the monitor to make it compatible with the Lasar system (without the jumper it works with mags). I'll post here anything that I learn from RMI.

Thanks

Alex I did with no troubles. I dont recall having to do anything special at all to get a very accurate reading.
Best,

I found the source of the problem - Lightspeed has changed the outputs with the "A" model of Plasma III, the newest. The output is an open collector type (I've forgotten what that means exactly). Lightspeed can modify the units, but first I am going to see if the RM Micromonitor can be changed instead. I'll keep you posted.

Problem Solved

I told Ron Mowrer of Rocky Mountain what I'd learned from Lightspeed about the Plasma III, "A" model (see previous post), and he said to make the modification outlined in the Micromonitor assembly manual pertaining to using a Hall effect pickup for sensing rpm. While the output from the Plasma is not a Hall effect setup, the concept and solution is the same. It was simply a matter of putting a pull up resistor in, and moving a jumper or two on the main board. My understanding is that having this sort of output from the Plasma will allow me to directly hook the two tach output leads from the two Plasma units together, if I want to see RPM with either system shut down. It will have to bother me a lot to climb back under that panel to solder a couple more wires in to get that feature (ain't happening).

In any case, it now works.