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Author Topic: Homing/limit switches- type No or NC? Not working on my CNC Router  (Read 910 times)

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Hello Forum,

I recently bought a used "Industrial Brand 48x48x10 CNC router. It has Mach3 Ver 2.0 loaded and running. It has 3 magnetic limit switches (LMF1-3005NA NPN Normall Open) installed but they do not stop the travel of any axis of the router? I used to have a Digital Wood Carver CNC router table and its limit/home switches that I installed were NC cherry switches. These worked fine. I was reading the Mach3 manual and they talked about double NC limit switches wired with an inline resistor. My question is, can I get these proximity switches to work or do I need to change them out? I want to have the machine operate with limit switches. I have a Tormach CNC 1100 Mill and its limit switches work, of course. Any constructive suggestions will be appreciated. Thanks BSA-LLC

Offline Graham Waterworth

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Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #1 on: February 18, 2020, 09:55:32 AM »
Some pictures would be good and also a picture of the ports and pins screen.
Without engineers the world stops
Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #2 on: February 18, 2020, 10:02:47 AM »
Thanks Graham,  Here are some pictures. Let me know if you need some other screen shots?  The proximity switch does light up when the tower moves close to the switch. I am sure that the inputs and outputs are NOT set up correctly. But I wanted to start with my question about the type of limit switch that should be used so I was not chasing a red herring. I have tried changing the active status in the Config set up and then the router just shuts down until you take it out of Active config and move it off the switch.   BSA-LLC

« Last Edit: February 18, 2020, 10:05:49 AM by BSA-LLC »

Offline Graham Waterworth

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Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #3 on: February 18, 2020, 10:52:48 AM »
You have 3 inputs turned off for the XY&Z homing turn them on and set the pins and port to what is in the line X++, Y++, Z++ and just maybe the homing will work if the switches are connected into pins 10,11 & 12 of the breakout board.

Then you can set the softlimits to stop the machine overrunning the extents.
« Last Edit: February 18, 2020, 10:55:21 AM by Graham Waterworth »
Without engineers the world stops
Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #4 on: February 18, 2020, 02:33:13 PM »
I have not tried your suggestion yet because I wanted to share these pictures of the BOB. Please see attached. I wish I could find a manual for this BOB but so far I have not found one. I did find out that when I try to turn the spindle on at Mach3 one of the large relays opens/closes/clicks and the green LED come on but of course the spindle will not start. I have to start and stop it at the VDF panel. but that is another problem I wish to solve!

Any help appreciated.

BSA-LLC

Offline ZASto

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Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #5 on: February 18, 2020, 07:40:01 PM »
On your picture: https://www.machsupport.com/forum/index.php?action=dlattach;topic=42570.0;attach=53179
you do not have any home/limit switch enabled. If you do not enable them, it is the same as you do not have them (fitted to your machine).
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Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #6 on: February 19, 2020, 09:18:42 AM »
Thanks for your reply. I have tried enabling the homing switches in Config Pins. When I do enable my CNC router comes to a complete stop if it reached one of the NO switches and I have to un-enable the switch to move the gantry. This functionality if OK for safety but no good for homing or normal operations. I am hoping to find out from the forum whether these NO switches should be changed out to NC switches like is shown in the Mach3 manual so that I can get the functionality of homing and safety stop. This is how my Tormach CNC mill works.

Offline TPS

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Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #7 on: February 19, 2020, 12:25:08 PM »
give this a try:

https://www.machsupport.com/wp-content/uploads/2013/02/Mach3Mill_Install_Config.pdf

chapter 4.5 there is normaly every answer you are looking for.
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #8 on: February 23, 2020, 10:49:11 AM »
Thanks, I have repeatedly reviewed this section of the Mach 3 manual. It calls for NC limit switches. I have NO proximity switches installed per the manufacturer. So I am trying to determine whether this will work with homing and limits? I was able to trace all 3 wires from the proximity switches (12V+, 12V-, and share from the switch and 12v+) I was trying to determine whether when one of these proximity switches is closed, is it sending too much voltage to my Chinese BOB? Its seems they are not going to 0V when the proximity switch is activated?

Thanks,

Offline TPS

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Re: Homing/limit switches- type No or NC? Not working on my CNC Router
« Reply #9 on: February 24, 2020, 03:05:35 AM »
the safest way would be to Switch a external relay with the proximity Switch and then use a contact of the
relay to Switch the Input of the bob.
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.