[Al_The_Man]

There are ferrous metal detector types, (there is also non-ferrous metal detectors), but this is a specific south pole detector.
Al.

[zer0fighter]

Wow, ok I'm stumped and confused, very.

Removed the sensor from the machine to test it out far away from the machine to rule out any interference. Either my multi-meter is possessed or it's aliens. When I put my multi-meter on DC 20v, and test the leads on my power supply, brand new 2a 12v DC power supply, it first reads 21, then slowly ticks down to somewhere around 13-16v. Can't get it to read properly on 12v. I put the same leads on my 48v power supply for my CNC machine and it reads 60v, should only output 48.

When I hook my power supply up to the sensor, and I tested the connection, it still read 13-16v. When I connected the positive lead of the multi-meter to the sensor output, I first saw 4v, then it did some bouncing around. I took my magnet and put it near the sensor, and it dropped to 0.06v. Great, that's expected. Now I remove magnet, nothing. Stays there. I try everything and it won't go back up to 4v-ish.


To make sure my machine setup and Mach 3 setup was correct, I put my Z limit switch into the index input, and flicked the switch with my finger a bunch and saw a pretty good representation of RPM from this.

So, my multi-meter is obviously not my friend anymore, it's old, so I guess I need a new one. Any other thoughts? My sensor fried?

Thanks again for everyones help above! I appreciate it.

Carl

[Al_The_Man]

With Fluke meters they tend to read twice the voltage or other weird reading when the battery goes low and before the low Batt ind comes on, I have seen a meter read 240vac on 120v ac supply.
Al.

[zer0fighter]

This POS doesn't even have the option to replace the battery!

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[Fastest1]

When I built my first controller (a Hobby Pro Cnc kit), Dave Rigotti pegged a bad battery in my meter entirely based upon a reading I gave him during diagnosis. It is the very first thing I suspect now days. Funny my cheap old RS meter never needs anything but the nicer units do.

[zer0fighter]

Sort of a side note, I have an optical sensor on my drill press that I tried pulling off to use on my lathe but without the multi meter working it's tough to figure out how it needs to be wired up. So at least I have options.

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[zer0fighter]

Bought a good multi-meter, did some testing. I think my sensor is dead, and I probably killed it. I put 12vdc to it on the bench, connect my multi-meter to the output & ground of the sensor, pass a magnet over it, and get no voltage reading difference. Sits at around 0.3vdc all the time.

I tried pulling the optical sensor from my drill press, and I can't get it to read on the bench either by passing something through the gap. Might be giving it the wrong voltage or something, or maybe I'm trying to read it wrong.

[Al_The_Man]

Bought a good multi-meter, did some testing. I think my sensor is dead, and I probably killed it. I put 12vdc to it on the bench, connect my multi-meter to the output & ground of the sensor, pass a magnet over it, and get no voltage reading difference. Sits at around 0.3vdc all the time.

I tried pulling the optical sensor from my drill press, and I can't get it to read on the bench either by passing something through the gap. Might be giving it the wrong voltage or something, or maybe I'm trying to read it wrong.

Are you using a pull up resistor when testing on the bench. If not that would account for no change in reading.
A 1k from output to +ve should be OK.
Al.

[zer0fighter]

Reviving this dead thread. AL, I'm trying what you suggested. I've got a resistor between the V+ and Ve+. IE attached the photo of the resistors I bought.

On my meter I get 12v between V+ and the ground, and I get 0.14v between the VE+ and ground, regardless of magnet or not.

Is the sensor dead?


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[zer0fighter]

Is my sensor dead?

[Al_The_Man]

It does not look good, that is the voltage you should get when fully on.
I am not sure where the other spec came from as re-reading the Digikey sheet, it shows 8ma? That a 1.5k resistor minimum on 12v? So 2k should be ample.
Al.

[zer0fighter]

Hi guys,
Wanted to thank everyone for their help. Managed to get the sensor working today. Well, a new sensor. Bought the same sensor as I originally did, wired this one up with the 1k resistor between the hot an sensor wire, and could get 11.6v and 0v for every pulse. Seems like my original sensor is toast. Waste of money but did learn a lot about sensors in the process.

Now just to get Mach3 tuned up to be able to do some threading!

Carl