Possible reasons why end stop status at max?

Hi,
I'm commissioning my Fisher D and have a problem with my Z-axis end-stop. M119 reports that z is triggered at max all the time regardless of the micro switches actual physical status. I have tried without the micro switch connected at all. Then decided to unplug the z-axis end-stop connected from the Duet board to eliminate the possibility of shorts in the cable. None of this changes the status of the z end stop. Any ideas? I have included two pictures showing what I have disconnected in case anyone spots a school boy error on my part:

The endstops are normally closed, so they'll show as triggered if they're not plugged in. Unplugging the endstop cable therefore won't prove anything.

When connecting the endstops, I made a mistake. The wires were connected to the two bottom pins of the endstop.
The wires must be connected the top and the bottom one (don't know if the colors are important, mine are blue top and red bottom).

I don't know if your problem is similar, but check to be sure.

Edited 1 time(s). Last edit at 08/08/2015 11:54AM by Greg_be.

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bluesign2k
The endstops are normally closed, so they'll show as triggered if they're not plugged in. Unplugging the endstop cable therefore won't prove anything.

I didn't know it was a closed circuit so with this in mind I was able to close the end-stop so I could test the Duet board was ok. Cheers

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Greg_be
When connecting the endstops, I made a mistake. The wires were connected to the two bottom pins of the endstop.
The wires must be connected the top and the bottom one (don't know if the colors are important, mine are blue top and red bottom).

I don't know if your problem is similar, but check to be sure.

Thanks...
Well I have found that even with my best efforts if their is a mistake to be made I'll make it. I'm now not a big fan of micro-switch end-stops...now. Plus I found the little connectors fiddly to use. I'm going to have to solder all the end-stop connections to be sure they are trouble free. But I'm still enjoying the build so that's the main thing.

I'm not a great solderer, but I found that gaffer-taping down each endstop cable got the job done.

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RogerBW
I'm not a great solderer, but I found that gaffer-taping down each endstop cable got the job done.

I think I shall have to use this technique too. I'm a bit paranoid about how much movement from rubbing the bowden tube my end-stop cable will have to endure.
Solder wise I took one wire filament from some old speaker cable i had and wrapped it around the joint of the micro switch and cable connector similar to a technique in making fishing flies. Then I blobbed some solder onto that which touch wood made an awesome bond.