Author Topic: Caution - Stupid questions within  (Read 1321 times)

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Offline jim_m

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Caution - Stupid questions within
« on: February 19, 2017, 09:18:51 AM »
Hi Folks
First post & yes I need assistance.
I'm trying to sort a combo lathe/mill machine on a Win7 laptop through a smooth stepper board.
It was retrofitted with a commercially built controller many years ago but has never been successful, probably from lack of time to sort it, rather than any fault of the controller, or so I hope!
Situation is -
- I have jogged all axis drive motors in both directions so I presume (?) that outputs are correct.
Which of these will actually work has been very random however.
- Spindle has not moved with the message "PWM bumped to min setting" displayed on any attempt. The min setting is not zero.....
- A couple of attempts to home have been sort of successful out of dozens of attempts, however the x axis has been first which I can't imagine is correct.
The contact with the home switch caused an E stop however.
I can't find a setting to change the order as suggested by the controller manufacturer, so I suspect the axes may not be set to the right pins??
- The 1 or 2 times that the x axis has retracted after homing has been pretty violent, despite my having set the homing speed very low.
- Other times any contact with the home switches has resulted in the switch remaining tripped with me having to manually move the axis until it untrips.
 - I have checked that operating the home switches manually does not cause an E stop
- Basically most of the time any attempt to jog will move a small amount (ie less than a millimeter) before the message (E stop requested)
I've found that even moving any axis manually by turning the motor by hand will do the same.
- I have presumed that the .xml file supplied by the controller manufacturer would be correct but now I'm not so sure.
I have manually activated the home (/limit?), door etc switches & they don't match the pin #s in the settings as I would presume they should??
- If I try to "Ref" X, Y or Z axes in the diagnostic window, I get "Requested home axis switch is active please fix, then home" displayed despite this not being the case in the plug in control monitor.
- It seems completely random just what, if anything might decide to work. A completely dead machine one day might be quite happy to work on 1 or 2 axes next day for no apparent reason then just as randomly s..t itself.
- I've completely been through the actual mechanics & made sure everything is lubricated & free to move.

I don't know how much of this info is actually relevant & I realise that I am presenting as a complete idiot.
I'm completely new to this & although I'm on a fast learning curve, it isn't fast enough & a lot of the info in the manual etc goes straight over my head @ the moment, hence my hope that some kind soul can give me a hand here??


Offline CES

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Re: Caution - Stupid questions within
« Reply #1 on: May 21, 2017, 04:47:13 PM »
Hi Jim,

  I'm running Win7 and Mach3 so things might be a little different.
First, you say all three axis move in both directions? Are you controlling X axis when moving X, Y of Y and Z for Z? If that is the case, your pins are correct. Jogging in the "+" direction verses "-" direction. If these are incorrect, the controller might be trying to move the Head down and actually moving it up or into the limit switch.
  When I Ref All Home, I have to ensure no home or limit switches are active (Diagnostics page).
If my acceleration is too fast, my motors just hum and get hot. The pulses go to fast and the motor can't do one before the next pulse starts which causes my motors to oscillate about 1/8 degree without actually moving.
Make sure the pin configurations are correct for your controller.


Offline joeaverage

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Re: Caution - Stupid questions within
« Reply #2 on: May 26, 2017, 07:10:32 PM »
sounds like you have a raft of problems. I think your best approach is 'disconnect everything' and then start hooking things up one
at a time diagnosing and fixing faults as you go. Your description suggests two or three basic faults and they are interacting in a manner
thats really confusing.

The fact that the axes jog sounds very hopeful. You say that you are using a SmoothStepper board. What model?. What version number
is the software plugin? I assume you have a BoB hooked to the SmoothStepper. What model BoB? Can you post a manual? How is the
SS and BoB powered?

The last question is not trivial. It sounds to me that your BoB is struggling to detect inputs which may explain why it works occasionally
but not others.

I would ensure that the power supply arrangements are per spec and then in the plugin disable all limit and home switches and then enable
and test one at a time. For instance if you disable all home and limits and then enable X home. You should see the Xhome LED on the
machine diagnostics page light up as you manually flick the switch. It tests the switch, the switch circuit, the  BoB input, the SS input and the
comm link back to Mach. If any of those components is faulty Mach will never reliably see the switch and can hardly be blamed for not doing
the right thing.

Repeat this process for each axis. Once you have the home switches working then you either work on homing OR limits. Do one or tother,not
both at once. If your home switches are at the very end of your axes travel the 'Ref All' can be pretty scary in that any fault which causes an
axis to drive in the wrong direction when at its nominal home position will cause it to drive off the end and crash. You need to sit there with
your Estop in hand to prevent it. If you could set, even temporarily, your home switches an inch or two inside the machine boundaries
you will find this process of testing much easier. If you cant do that then consider setting up the limit switches before trying the Homing

The limit switches should be enabled one at a time and tested. Most users hook all the limit switches up in series so that operating any one
of the switches disables the machine. It is still important to test that each of the 6 switches can do that.

You can now set up the Homing settings. Note that its possible for the limit switches to interfere with the Homing process and you may have to
temporarily disable or ignore limits while homing with the chance of a crash. Its for this reason I prefer to have separate limit and home switches,
it certainly easier to understand!

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