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Author Topic: Spindle and Limit switch  (Read 8431 times)

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Spindle and Limit switch
« on: April 03, 2011, 02:38:04 PM »
Hey guys,
Its been about a year since I worked on my Bridgeport boss 6 retrofit.
My problem is when I start the spindle using MDI, my z++ limit trips .
-My z++ limit and z home is shared by a optical sensor via pin 12 and normally closed.
-My z--, x++,x--,y++, and y-- is in series via pin 11 and is normally closed using mechanical switches.
- I do not have and x or y home switch yet.
When I home the z it homes correctly.
When I exceed the z++ limit it trips correctly

however, like I said when I start the spinlde via mdi through mach3 (T1S1000m3;) the z++ limit trips
I know its the z++ limit because when I deactivate the z++ in the inputs page, the spindle runs and does not trip a limit.

I do use a vfd in my machine.

Has anybody have had this issue, thanks Joe

I plan to finally post pictures of my design shortley thanks to all those who have helped me (hood).

Re: Spindle and Limit switch
« Reply #1 on: April 03, 2011, 02:54:24 PM »
Do you use shielded cable for your limit switches.

If not, this could be the problem.

VFD generate a lot of electrical noise.


Jeff
Re: Spindle and Limit switch
« Reply #2 on: April 03, 2011, 02:56:12 PM »
You could also try a value of 2000 in the debounce setting in general config, on the top right of the page.


Jeff
Re: Spindle and Limit switch
« Reply #3 on: April 03, 2011, 03:31:18 PM »
Thanks Jeff,
Yes I use shielded cable.
I have tried the debounce also.
If i eliminate the z++ as a limit in the inputs page I do not have a problem, wondering if it is a software problem in my control.
Re: Spindle and Limit switch
« Reply #4 on: April 03, 2011, 04:23:24 PM »
Do you see the led in the diagnostic page.


How close are the Z home switch and the Z++ switch from each other.

Does it trigger at the moment you start the spindle.

I've seen it when the spindle start, there was a very very little movement of the head, enough to trigger the limit switch.

The point where the switch is open or close when homing is maybe 1/1000 of an inch so already had this problem before.

Jeff

Offline Hood

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Re: Spindle and Limit switch
« Reply #5 on: April 03, 2011, 05:06:48 PM »
Could you have duplicate pins set, ie you have the same pin configured for your spindle as you have for the limit
Hood
Re: Spindle and Limit switch
« Reply #6 on: April 03, 2011, 09:49:42 PM »
Hood I will check to rule that out !

Jeff I have tried to activate the spindle away from the home switch and limit, the quill is halfway down
Let me rephrase that, my z++ limit and z home is a optical sensor ( they are the same switch) on pin 12.
So I have only a mechanical limit for z--  at bottom and a optical sensor at top for both limit and home.

Joe

Re: Spindle and Limit switch
« Reply #7 on: April 04, 2011, 08:08:42 PM »
Hood I have checked my pins in mach 3 under motor settings. the spindle outputs are 16 and 14 for step and direction.

I am also using the usb from the computer to power the bob and spindle board.
I have also used straight connections from the power supply by cutting a molex connection.

I went to usb from the molex to see if that would make a difference, it didn't.

Should I have a dedicated power supply for 5 volts, could this be causing a problem?

Offline Hood

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Re: Spindle and Limit switch
« Reply #8 on: April 05, 2011, 03:00:12 AM »
Dont think power should be the issue.
What kind of switch is it? If a mechanical switch is there a chance that vinration is the issue?

Hood
Re: Spindle and Limit switch
« Reply #9 on: April 05, 2011, 07:08:57 AM »
It is a optical switch, I am using it to control the Z++ limit and z home via pin 12
I have a mechanical switch on z-- limit, and vibration does get into the switch at times, which i will have to investigate a little further after I am past this task.

Hood I have noticed in other threads you have built a beautiful bridgeport retrofit. May I ask, did you just use the mechanical switches as both homes and limits.
Or did you use the mechanical switch as a limit and put a more accurate homing sensor such as a slotted optical sensor. If so how did you mount the optical switches under the machine for the x and y axis. I bought and use pmdx slotted switches for my machine.

Thanks