How to add a tach to a B7100d

[drewscruis]

I'm looking to add a digital tach to my tractor, has anyone done this before and have any suggestions, all the digital tach's i've come across are for gas engines where you wrap a signal wire around a sparkplug, so since there is no spark plug on a diesel what is my next move?

 

[kubotasam]

Here is one way--http://www.tinytach.com/tinytach/diesel.php


I have not put one on my tractor but it seems very easy.