If you wish to connect a tachometer to the ECU, the ME221 and ME442 Wire Ins offer a dedicated Tacho Pin in the Output Settings.


When set as "tacho" in the IO settings, it will offer a 12v square wave which will output pulses as per configured in the Tacho Output Settings (under System in the Entity Tree).


The Tachometer output can be used as a low current low side driver for driving up to 0.5A - useful if you wish to use it as an extra relay driver, for example for a second cooling fan etc.


Tachometer Modes:


You can set the tachometer output to operate in a few different modes, detailed below.

Toggles per Revolution

This will toggle the tachometer pin from High to Low then back to High the amount of times per the engines revolution as set by the the "Toggles per revolution" setting. This must be a whole number, ie 1,2,3,4 etc.


Mirror Coils

This will make the output act like all of the dwell signals of the coil lines combined, so for example a short 3.5ms (or whatever the dwell table is set to) pulse each time ANY coil fires.


Mirror Coils Inverted

As per mirror coils, only a ground pulse will be given instead of a 12v pulse each time the coils are fired.