HEI module necessary for V3 pcb?

[olie05]

From what I have read the HEI module allows you to convert an AC VR sensor signal into a square wave signal.

 

if that is true, why can't we just use the optical distributor with the available "optical input" circut option for the V3 pcb, thus eliminating the HEI module?

 

 

50. Next you need to make a decision. There are two input circuits for the tach signal:

• The Hall/optical/etc. circuit takes the square wave input from a Hall sensor, optical sensor, or points. It can also be used for triggering off the coil (but only if you are not controlling ignition timing).
  
• The VR circuit takes the AC signal from a variable reluctor sensor and converts it to a square wave for use by MegaSquirt.

The Hall circuit can be built two ways - for a digital signal such as a Hall sensor or optical sensor (step 50.a.) or for a coil negative terminal (50.b.). these are the same circuit, but different components.

[mario_82_ZXT]

The way the sticky has been set up has never used the HEI on the input side of the RPM signal.

 

The dizzy automatically outputs a wave (maybe even square...) that MS understands.

Mario

[mobythevan]

Correct, there is one schematic in the sticky that uses an HEI module on the input for VR circuits, but that only applies to V2.2 boards.

 

It was never intended that anyone use an HEI module on the input side for optical trigger.

[olie05]

ok my nose is stuck to far into the book, and at the same time not far enough into it

 

So, HEI is totally unnecessary when using a vb921 coil driver, yes?

 

you can tell I don't want the HEI module!

[mobythevan]

yeah, thats correct, no HEI with the coil driver.