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Author Topic: Home and/or limit switch  (Read 12444 times)

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Offline Kristin D

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Re: Home and/or limit switch
« Reply #20 on: September 15, 2008, 05:09:53 PM »
Brett,

Can't seem to get the network connection to work right now for the XLS and my usb drive gave up the ghost a while back, however here is a bad picture of where the switches are mounted. The X & Y switches are mounted off the rectangular motor mounts and contact the stationary bed of the machine (aluminum casting that the arrow is pointing left at the x home area) the Z axis switch is up top and contacts a accuator mounted on the spindle slide. Think I already figured out the crash factor, set the Y -- limit and ran into the switch and had to power down to manualy back off the switch.

Kristin

Offline Hood

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Re: Home and/or limit switch
« Reply #21 on: September 15, 2008, 05:22:31 PM »
Ok first thing is you can set AutoLimit Override, that will allow you to back off a hit limit switch but be aware that you can jog the wrong way so be careful :)
Easiest way is to have the home switches for X at the left hand end of the table for X, and for Y at the column, Z is at the top. If you do it this way then setting up Softlimits is easy, you enter zero for X and Y Min and Z Max, then X and Y Max and Z  Min is the distance of travel on each axis.
 If you have the limits at the other extremes of the axis you still set the Min and Max for each axis the same but you have to enter a Home Off distance for each axis. The reason for this is you want Mach to know that when your tool is at the corner of the table I have marked it is the X and Y zero position.

Hood

Offline Hood

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Re: Home and/or limit switch
« Reply #22 on: September 15, 2008, 05:23:49 PM »
Oh Also remember Z Min will be a negative number.
Hood

Offline Chaoticone

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Re: Home and/or limit switch
« Reply #23 on: September 15, 2008, 05:33:05 PM »
I also meant to say, try to mount your switches in a manner so that physical smashing isn't possible.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!

Offline Kristin D

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Re: Home and/or limit switch
« Reply #24 on: September 15, 2008, 06:36:46 PM »
OK,

Think I have it(famous last words!) Where is "autolimit overide" general config? I would have done otherwise but there reall is not any other places to mount switches so I guess I will have too set up the offsets.

Kristin

Offline Hood

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Re: Home and/or limit switch
« Reply #25 on: September 15, 2008, 06:40:27 PM »
Think its on the settings page, been a while since I looked at the standard screen so may be on Diagnostics but its one or the other.
Hood

Offline Kristin D

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Re: Home and/or limit switch
« Reply #26 on: September 16, 2008, 12:07:36 AM »
Hood,

Yup was on the "settings" page and I was able to overun the switches by .010 and not crash! ;D

Got all three axis figured out and zero'd with the "safe limit" keeping from crushing any now, Wonder if I should go buy Igor a Glock like Brett's Chimp, good lab assistants are hard to find but I wonder if armed lab assistants are worth having, normaly I am the only one armed in the shop and it would be a pity to loose that advntage! Perhaps a super soaker and I'll just leave a power panel open! :D

Kristin

Offline budman68

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Re: Home and/or limit switch
« Reply #27 on: September 16, 2008, 05:13:47 AM »
Glad you got it sorted Kristin-  :)

I also meant to say, try to mount your switches in a manner so that physical smashing isn't possible.

Brett

Unfortunately I was mounting my 3rd limit switch (Y axis) while remembering this so I'll be redoing my Z and X axis at some point in time. If I crash, I have backup switches, lol!

By the way, since I'm hoping to setup for coolant or mist in the future, what small limit switches can I use for that application? These (limit switches in general) aren't all sealed are they?

Thanks,
Dave
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Offline Hood

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Re: Home and/or limit switch
« Reply #28 on: September 16, 2008, 06:26:32 AM »
I use these http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0335081 on the lathe for limits and home switches, they are accurate and waterproof but fairly large and expensive. For homing on the lathe I use the servo drives as they home to the index, what happens is the drive starts homing until it hits the switch, it then backs off until it sees the Index pulse from my encoder and then sends a signal to Mach to say its homed.
 I have these switches  http://www.rapidonline.com/Electronic-Components/Switches/Microswitches/IP67-Microswitch/74548  on the turret and toolp[ost on my lathe, they seem to be pretty good as far as being coolant proof and are certainly accurate enough for the toolpost and turret but never =measured for use as limits.

Hood
« Last Edit: September 16, 2008, 06:29:47 AM by Hood »

Offline Chaoticone

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Re: Home and/or limit switch
« Reply #29 on: September 16, 2008, 08:46:36 AM »
Dave, i use prox switches. There is no contact, they repeat accuratley, and coolant doesn't bother them. You can get some that will sense only certain materials as well. That comes in handy at work on our robot cells. If it is an Alum. cell, we get ones that can only see steel and use steel targets. You can get PNP or NPN and 2 wire NO and NC. Here is a link to an example. http://web4.automationdirect.com/adc/Shopping/Catalog/Sensors_-z-_Encoders/Inductive_Proximity_Sensors/8mm_Round_(AE_Series)/Standard_Sensing_Distance_(AE1_Series)/AE1-AN-1A

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!