Hall effect sensor Failure

[Martin]

Hi,

Im running a Toyota 1GR-FE ( 4 litre v6) on a M600. The hall sensors on the 1GR-FE is a 5volt supply and its voltage levels are not the same as most Hall effect sensros. Levels are 1.026v when floating and 0.216v when triggered. As most of you would know the trigger levels on a M800 is slightly above 3volts so this particular sensor does not trigger the ECU. The workaround was to install a pull-up resistor to keep the voltage level above the trigger level when not triggered so that the ECU can see the triggers. The problem im having is that one particular (bank1-sync) sensor fails (twice in 1 month). The other bank wired to Dig1 for cam position measurement has never failed.

I know Dig inputs have a 4.7kOhm pullup to 5v, but i dont know about the Sync input. Both cam sensors (sync and Dig1) have the same value pullup resistors. Does anybody have any idea why a hall sensor would fail like this? Could it be the pullup that damages the sensor over time?

Thanks
Martin

[MarkMc]

Hi Martin,
The ref and sync inputs have a 5v internal pull-up switched in when you configure them to Hall in the software. This setting also switches in the set trigger levels. The Hall input setting is designed for an open collector Hall sensor where the SENSOR is switching the 5v signal from the ECU sync/ref pin to a 0v pin, i.e the sensor is simply shorting the ref/sync pin to ground.

We have seen a couple of different sensors that switch between different levels and an not really compatible.

I am away from the office at the moment so do not have lots of information with me but maybe someone back at the office can help. Have you tried switching the ref/sync sensor type to Magnetic and doing a ref/sync capture to see if there is any signal form the sensor (without external pull-ups?

[Martin]

Hi Mark,

No I havent tried it in mag mode, but the is signal with no pullups, just not at the level where the m600 wants to be triggered. Do you suggest i try mag mode anyway?
Captured signals as follows...all in hall mode.

1.026v open 0.216v closed no pullup
4.106v open 1.008v closed 1.8kOhm pullup to 5v
3.638v open 0.684v closed 4.7kOhm pullup to 5v

most hall sensors ive seen float at about 3.7volts when open. At the moment there are 4.7kOhm pullups to both the sync(bank1) and Dig1 (bank2 cam position)

Would running a Hall sensor in mag mode be okay? (to make triiger levels adjustable) and also.... what is the difference between logic level and hall sensor modes?


Thanks

Martin

[PeteS]

Hi Martin
You could use the magnetic mode.
Conduct a ref sync capture
Use the off set voltage in the mag set up and set it midway between your high and low voltage levels as obtained from the capture.
Then set up your mag levels to suit.
Cheers