How to install a limit switch for Z table

[NickWL]

I have just assembled a LightObject Z-table for my K40. So far, so good.
I have been racking my brains (ever since I ordered it) on how to set up a travel limit microswitch for the table. Now that the table is ready to go, the need for a solution is even more pressing!
HELP!! Can people who've done this please either tell - or preferably show, with a photo - how they've solved this issue.
Many thanks.
Nick

[Tech_Marco]

Nick:

Since you asked, I have made one video for you. No charge

http://www.youtube.com/watch?v=Jr007MpBRgQ

Full size: http://www.youtube.com/watch?v=Jr007MpB ... e=youtu.be


Marco

[NickWL]

Thank you Marco - especially the 'no charge' bit (although I bet Customs will slap a tax on it if they find out!).
I hadn't realised I ought to go for upper AND lower limits - so that's a bit of good news.
But...
I have a honeycomb on top which is about 2cms thick and I was hoping to measure the distance from the face of the lens to the top of the material (itself being on top of the honeycomb). i.e. Autofocus.
I think what I see in the video is just a pair of 'safety' stops to prevent the table grinding itself into powder?
Should I be treating autofocus as a completely separate problem? I'd though it was part of the DSP controller - don't know why I thought that, but I did.
Nick

ps I've just watched the video again and I see no DSP. IS this just a standalone up/down setup?
pps. Can you (or anyone) point me towards a circuit digram for this - there must be one in the forum somewhere, but I can't find it!

[NickWL]

I've also found that tightening the brass nut-pairs on the moving platform makes it almost impossible for the screw to turn. Should they be tight? And which way up?


So many questions...

[Tech_Marco]

No, you don't need two limit switch if and only if you're using DSP controller. I'm simply using a 1-axis motor controller to control the power Z table. I just want to let you know where and how to install a limit switch. Ahi... I though you could figure it out that. Remember that I can't so everything in every way like with or without DSP.... that will be killing me as I don't have that much time to do that

Here is the controller: http://www.lightobject.com/Stepping-mot ... -P729.aspx

Manual: viewtopic.php?f=16&t=1493


Forget about auto focus on the K40. Don't waste time and energy for that fancy things. If you have big machine and dealing with so many different size object then auto focus (not really full automatic) may be worth to try. By the way, I just designed a auto sensor for the auto focus and it should be in production on next month


Marco

[NickWL]

Thank you again Marco - especially for the advice about autofocus - I'll forget that now and make my life much easier.
It was finding somewhere to put an autofocus sensor that was giving me a hard time, but I'd never have thought of your arrangement as long as I was wasting brainpower on autofocus - now that's out of the window it all get much easier!
Well done Marco

[billw2004]

Hi Marco,
Nice video , but can you send or publish wiring diagram, of both switches to DSP. I can get lower one working(Z-),but where does wires go into DSP for upper limit switch ?
Many Thanks
Bill Watson..

[Tech_Marco]

Bill:

You just need to use one limit switch (upper one) for homeing. You use the 'Range" to control how far it can reach to the bottom through software control.

If you're not using DSP but the motor controller, then you need to use two limit switch and it is quite handy without using the DSP for Z control


Marco

[billw2004]

Hi Marco,
Using DSP,therefore will just use one switch.
Thanks for prompt reply.
Bill Watson

[NickWL]

I ended up using no limit switch - seems fine. When I had a (lower) switch the whole system would lock up once it had been triggered!
I do up/down on the z/u button on the controller interface and - at Marco's advice - don't even try to auto-focus.

[Tech_Marco]

See this custom made limit switch DIY
viewtopic.php?f=16&t=2112


Marco