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Offline stirling

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Re: Setting machine Coordinates
« Reply #10 on: June 26, 2010, 01:02:32 AM »
from what you've said you seem to be wired and configured right so I'm guessing noise - experiment with a bit of debounce on the config/general config page (top right).

You can't disable e-stop - not allowed - but you can de-activate it!

early in the day here but isn't 0.5" lead, 2 turns/in not 5?

Cheers

Ian
« Last Edit: June 26, 2010, 01:12:41 AM by stirling »

Offline Hood

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Re: Setting machine Coordinates
« Reply #11 on: June 26, 2010, 11:45:09 AM »
As Ian says you  cant disable it and really even the smallest of Machines should have an external E-Stop button but for testing purposes just change the active state of the E-STOP in Ports and Pins.
Hood
Re: Setting machine Coordinates
« Reply #12 on: June 27, 2010, 05:25:44 AM »
It seems to me that you get noise on the limit switches.
Check if they triggers when e.g. you jog the machine (when they should not trigger), it can be noise from steppers....

You can filter the limit switches in Mach3 -> Config -> General Config -> Debounce Interval.

The input is low pass filtered with a time constant set in the Docunce interval.

If you use the limit switches for home functions too, then with too high debounce value the home will be unprecisious, so try to find the lowest aquadate value.

Also you may put some HF ceramic caps 1..10nF on the LPT port inputs to filter noise out.

BR,
Balazs
Re: Setting machine Coordinates
« Reply #13 on: June 28, 2010, 08:16:12 AM »
I will try the debounce and filter caps.

For testing purposes I have disabled the EStop, but do have an external Estop switch to disable power. I realize this is not ideal for the long run but should suffice for troubleshooting purposes. 

The home switches do not appear to be triggering during jog operations. Voltage on the input pins remain at 3.9 - 4.1 VDC during jog operations and are grounded when activated.

UPDATE: Disabling the EStop had no effect on the problem

I appreciate all the help you are providing.

Castleworks
Re: Setting machine Coordinates
« Reply #14 on: June 28, 2010, 08:56:33 AM »
Hi Kevin,

Can you explain the problem a bit more detailed?
You mentioned that when you press "Ref all home" button Mach thinks that your axis is already at home, right?
From what do you think that Mach is thinking this way?
What happens when you press the Ref all home button, axis starts to move, or not moves at all?
Any text appears in the "Status" field? (right next to e-stop button)

I think you should write down step by step what you do and what happens to let me see things closer.
Also a wiring diagram of your limit/home switches may help some.

Did you try to home axis separately? Go to diagnostics screen and there is RefX, RefY, RefZ etc. buttons,
so you can test axis homing separately, hopefully then you can locate the error if it is a connection problem or noise on an input.

And as Ian and Hood mentioned you cannot disable the external E-stop, ofcourse there is a trick to disable it with writing a port number which not exist, e.g. port 0 into e-stop setup, but this is not recommended, because it will leaves the machine without safety, so don't do this....


Cheers,
          Balazs
Re: Setting machine Coordinates
« Reply #15 on: June 28, 2010, 12:36:24 PM »
Hi Balazs,


I will throw a lot of information at you here...so please ask if I need to clarify anything. I am working on getting a schematic in a form to post.


Sequence of step I have taken......

Manually jog Y axis until the home switch activates. I am confirming activation in three ways.... pin 13 transitioning from 4.0 VDC to 0.0 VDC, LED on BOB turning off and LED indicator on proximity home switch turning on.

Manually jog X axis until the home switch activates. I am confirming activation in three ways.... pin 15 transitioning from 4.0 VDC to 0.0 VDC, LED on BOB turning off and LED indicator on proximity home switch turning on.

Manually jog Z axis until the home switch activates. I am confirming activation in three ways.... pin 12 transitioning from 4.0 VDC to 0.0 VDC, LED on BOB turning off and LED indicator on proximity home switch turning on.

NOTE Manually jogging using the arrow key for X & Y Pg up and Pg Dn for the Z axis) and they are responding properly (at this point, more on that in a minute)


Once all home switches are activated and the table is in its home position, I individually click on "Zero X"  "Zero Y"  "Zero Z"  This sets the DRO's to zero.

I then manually jog the table to the middle position on each axis.

I then click on "REF ALL HOME"

Each axis begins to move (in the correct direction)  sometimes each axis will only move a few steps and stop , other times it will move one or two rotations of the ball screw.  When each axis moves the DRO's respond correctly HOWEVER once the table stops the DRO value returns back to the original value it started from, even though the table has moved.  For example if the X axis were at 10.0 inches and I start homing, the axis moves, and the DRO responds correctly and may move to 9.0" but once the table stops, the DRO returns to 10.0 even though the table has moved and stayed at its new position of 9.0"

No message appears in the status screen when this is occurring.

I have used the diagnostics screen to individually home each axis. When I do this each axis behaves the same EXCEPT the Z Axis......When I home the Z Axis, it moves in the incorrect direction (but still only briefly)  AND if I go back to the main Program Run screen to manually jog the table, X & Y axis behave correctly...however the Z axis direction does not work (regardless is I tell it to jog up or down....it only jogs down.  The only way I have been able to get it to reset correctly is to turn everything off and reboot.

Following reboot I get the same results from the above procedure including the problem with the Z axis. I have tried this several times with the same results.

I really appreciate everyone trying to help me resolve this....I am certain I am overlooking something obvious
Re: Setting machine Coordinates
« Reply #16 on: June 28, 2010, 12:37:52 PM »
One more piece of information......


At no time on the diagnostics screen do I see the E Stop indicator activate.
Re: Setting machine Coordinates
« Reply #17 on: June 28, 2010, 01:36:31 PM »
Hi All....

ISSUE RESOLVED:

Asking me for a schematic for the home switches caused me to take another look at how they were wired and to confirm they matched the schematic. This led me to finding the error of my ways.

The rest of the story......

Proximity sensor home switches were wired to the correct BOB input with a pull up resistor to 5VDC (5VDC source on the BOB)....the NPN sensors operate on 6-32 VDC, so I was powering them by a separate 12VDC supply. Originally I had them powered off the BOB 5VDC source but then realized they would not operate on 5VDC so I powered them from a second power supply.

I failed to move the pull up resistor over to the 12VDC source and left it on the BOB 5VDC source. These two supplies do not share the same ground reference, so I suspect they were fighting each other.

Once  I moved the pull ups over to the 12V source....all is operating correctly and home properly.

Thank you all very much for your assistance.....until my next oversight :)

Kevin
CastleWorks

Offline Zaae

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Re: Setting machine Coordinates
« Reply #18 on: June 28, 2010, 01:45:26 PM »
Castle,

Very good! Glad you figured it out.

As far as the Z going the wrong way, have you tried changing the 'home neg' box for the z axis in homing and limits? Not being able to jog Z one direction probably means that mach thinks its at the soft limit for Z.

Re: Setting machine Coordinates
« Reply #19 on: June 28, 2010, 04:35:23 PM »
Z axis is running good now

Stirling.....you were correct .5 lead equals 2 revs/ inch.....all is much better after that change as well.

Thanks all!

www.CastleWorksKC.com