vintagebuilder
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| posted on 19/1/06 at 09:52 PM |
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Sender magnets
Good Evening,
I've fitted a Greengauges electronic speedo with a reed switch obtained from Farnells. I've got four magnets Araldited to the half-shaft
tin can. The sppeedo doesn't work however. Looking through all the posts on this problem I came across a comment that the magnets should be
fitted with the pips facing downwards. I'm sure I read somewhere that the pips should be face up. Could this be the reason my speedo
doesn't work or doesn't it matter if the pips are up or down?
Hope someone can help.
Regards
David
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rusty nuts
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| posted on 19/1/06 at 10:01 PM |
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Can't remember having problems with the magnets apart from the fact they didn't send any but I think they show a method of testing the
reed switch operation on thier website? Also worth double checking the wiring?
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bilbo
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| posted on 19/1/06 at 10:05 PM |
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It could be then reed switch that's causing the problem. Reed switches are mechanical devices and I'm not sure up to what speed they can
operate at. My guess is that over a certain frequency they can't open and close in time. I would suggest you try something solid-state instead,
such as a hall effect transistor.
Hope this helps,
Bill
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DarrenW
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| posted on 19/1/06 at 11:12 PM |
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ETB say magnets must be fitted pip down. The pip denotes the polarity so it is very important. Not sure how this relates to greengauges
ETB sell the magnets as a spare.
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givemethebighammer
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| posted on 19/1/06 at 11:42 PM |
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I had the same issue with my VDO gauge and reed switch. ended up moving the reed switch further away from the magnets (now about 5mm away). Seems like
if it is too close it just doesn't work at all.
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indykid
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| posted on 20/1/06 at 09:09 AM |
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don't know if greengauges are the same, but on my CAi telemetrix gauges, there was a 12v pull up that needed connecting before the gauge would
read.
tom
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02GF74
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| posted on 20/1/06 at 11:00 AM |
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quote:
Originally posted by DarrenW
ETB say magnets must be fitted pip down. The pip denotes the polarity so it is very important. Not sure how this relates to greengauges
Polarity does not matter for read switches.
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vintagebuilder
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| posted on 20/1/06 at 11:06 AM |
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Morning All,
Just to confirm that polarity does not matter with Greengauges speedo. Spoke to Greengauges this morning and found them very helpful.
Ah well back to the drawng board.
Regards
David
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Dave J
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| posted on 20/1/06 at 04:30 PM |
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ETB instruments state that the dimple in the magnet indicates magnetic north.
This dimple should point to the sensor otherwise the sensor will eventually become de magnetised.
Cheers
Dave
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