MS2 - VR Input for tach signal

[krisr]

I left mine adjusted to the max when I built the PCB. If you have a slow starter, having it trigger at 70rpm isn't a bad thing. My starter cranks at about 150rpm.

[Bruce Bowling]

I set both of my pots at full counter clockways rotation. I can pick up rpm as low as 70 rpm . I have the harness laying in the floow and a Makita drill taped to pro billit dizzy. I can get rpm from 70rpm up to 1700, max my drill goes.

I noticed as I increased ether POT it wouldn't read as low rpm.
The instruction said R52 all ways counter clockways, R56 all wasy clockways..this didn't work for me.

Do i want to be able to trigger MS at 70 rpm? or should it be higher?

The signal from the VR sensor depends on the spacing of the tip of the VR sensor to the reluctor. Closer positioning of the VR tip to the reluctor will increase output signal, so the circuit will trigger at lower RPM. Small adjustments can yield big changes in signal strength, it depends on the sensor and reluctor geometry.

70 RPM is a tad more than one engine revolution per second. This should be workable, but under low battery and/or very cold temperatures the cranking speed could be slower, it really depends on the engine and environment.

- Bruce

[Bernard Fife]

The instruction said R52 all ways counter clockways, R56 all wasy clockways..this didn't work for me.

busta9876,

All the instructions I have written say 'both pots fully counter clockwise' (unless I have made a mistake).

If you are aware of any contrary instructions, could you give me a link so I can fix it?

Do i want to be able to trigger MS at 70 rpm? or should it be higher?

70 rpm should be fine - you certainly don't need it to be higher - most engines crank over at 150 to 250 rpm, except in extreme conditions (as Bruce says). You will get a feel for this when you do a few datalogs and can see the cranking speed under various conditions.

Lance.