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Offline Hood

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Re: Estop at wrong times web cam how do i ? help
« Reply #10 on: December 29, 2007, 03:18:56 AM »
Bill I think it would be better for you to get the soflimits working as they should, you should not have to add code to your Ref button to achieve it.
Hood

Offline Chaoticone

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Re: Estop at wrong times web cam how do i ? help
« Reply #11 on: December 29, 2007, 06:27:09 AM »
Guys, listen to Hood on this one. He'll get you straight. He gave me a lesson on this a couple days ago. Can't mess with the Hoodster.  ;D

Brett
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Offline jimpinder

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Re: Estop at wrong times web cam how do i ? help
« Reply #12 on: December 30, 2007, 10:38:13 AM »
Surely the only way to get the referencing working is to set the soft limits outside the co-ordinates needed by the home switches. I use micro switches, and when these are hit, they travel quite a distance (relatively) before they stop. I can't remember by how far but it might be 0.0500. The axis then backs off until the switche closes and then the DRO goes to zero.

It follows therefore that my softlimits must be at least 0.0500 below zero, or the soft limit will trigger.

Coupled with that, of course is the fact that my z axis - the main lathe axis, can be de-coupled manually, moved to a short distance from the switch, the re-coupled and the axis told to home ( this saves time becasue the traverse time is so long).  This shouldn't actually make much difference, because the relative DRO position should always be several inches above zero in a +_ve direction.

The problem is, of course that, in setting software limits, if you set them too high - they will trigger an E stop. If you set them too low, (on my system ) they will bend the metal actuator on the micro-switch.
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Re: Estop at wrong times web cam how do i ? help
« Reply #13 on: December 30, 2007, 11:42:35 AM »
Hi  all  Ok  Today  remberd  to  take a note  of  my  soft  limit  settings  and  take usb  memory  to  copy  files 

X axis   reversed  No  soft  max 586  soft  min 1   slow zone  15  home  off 0000  home  neg  yes auto zero yes speed 20%

Y axis   reversed  Yes  soft  max 459  soft  min 1   slow zone  15  home  off 0000  home  neg  yes auto zero yes speed 20%

X axis   reversed  Yes  soft  max 0  soft  min -35  slow zone  1 home  off 0000  home  neg  NO  auto zero yes speed 20z

ok  also  found  Xml  document    whitch  i  have attached 

hope  this will shed  some  light  on  the  problem 

regards  Bill






 

Offline Hood

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Re: Estop at wrong times web cam how do i ? help
« Reply #14 on: December 30, 2007, 01:55:39 PM »
Bill set your min for X and Y to 0.
 You have it set to 1 so every time your axis moves below 1 (in machine coords) you hit the softlimit.
 Remember that the zero that Mach sets, as its machine coordinate, is after the switch has closed, thus setting a 0 for your softlimit min should never activate the physical switch. You can test this out by doing a rapid move towards your min limit, if Mach cant slow quick enough you need to set up a bigger slow zone, how much depends on lots of factors, motor tuning being a major one.
Hood

Offline Hood

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Re: Estop at wrong times web cam how do i ? help
« Reply #15 on: December 30, 2007, 03:01:33 PM »
Jim
 I am having trouble visualising exactly what you are meaning, so if the following doesnt bare a resemblance to what you mean please ignore.
 If your home switch is hit and it takes a while before the axis stops and reverses that is neither here nor there for Mach as Mach does not set the Zero (machine Coordinate) until the axis has reversed and the switch has closed again. Therefore if you set the min for that axis as 0 it should never get as far as activating your limit switch because the zero position is when the switch closed. As I said to Bill above if you rapid to the limit and the soft limits dont kick in in time then you need to set your slow zone larger so that Mach can decellerate your axis and not overtravel the soft limit.

As for your Z axis, I dont think there is any way that you could possibly set up softlimits as your limits can be moved. Obviously you could set up softlimits for min and max but every time you reposition the Home switch (or trigger for it) you would have to set up new softlimits.

Just out of curiosity, do you have your X axis set up so that the zero position is spindle centre, this is the normal way to do it on a lathe, that way every time you command an X move it will cut that diameter, eg if you are using Dia mode and you tell the X Axis to be at X40 you will cut 40mm Dia. This may not be of much use to you depending on your setup, ie if you have tool turrets/posts with fixed tools then you set it this way, if you have a Quick change Toolpost with all your tools in holders then it would also be an advantage to work this way. However if you have a conventional toolpost and are changing tools in and out all the time then it is probably of no advantage for you to have your axis set to zero at spindle centre.

 

Hood
Re: Estop at wrong times web cam how do i ? help
« Reply #16 on: December 31, 2007, 11:20:57 AM »
Hi  Hood 
thanks  for  that   reset  to  zero  and  now  works    i have had   a  play  with  this  and  find  the following 
when  you  call a  ref  the system  ingnores  the soft limit  seting  and  will drive  the axis back on  to  the  limit  switch  this  may  take  you  through the soft limit  value in my  case   1  so  may  drive  to  somthing  like -50  this  is  ok  because  the system  in  a ref call ingnors  the soft limit seting   once the axis is refranced  and  that  routeen  ends  then soft limits  become active  again 
as  my  system was  set  to  auto  zero  the  MC   dro   this now shows 0 my  soft  limit  set  for  1 the system  would  see this as a  fault  and  trip the estop .

yes  can see  where  this  is  going  wrong  now      if  you  do  not  auto  zero  the  dro  then  the  system  may  trip  even  if limit is set  to 
0  as  it  would  leave  the  -50  value 

Ok  it  could  be  that  i  am  expecting  too much from  the system   i  was expecting  the soft  limit  settings  to  allow me  to  define a work  area on  the table  that once  refranced  the  tool  would  not    move  out  of 
I  now  see  that  to  do  this  would  need  the  reff  call to  set  the  system on  the  limit  switch  back  it  off unitil the switch  closed again  set the MC dro  to  zero and  then  move  the axis  to  the min soft limit value befor finishing  so  the system  would  not  trip
it  would  need  to  this  on  all axis .

Ok  something  to  think  about 

thanks  bill





Offline Hood

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Re: Estop at wrong times web cam how do i ? help
« Reply #17 on: December 31, 2007, 11:56:17 AM »
Bill,

 The softlimits are there so that the axis will stop in a controlled manner rather than triggering a physical  limit and thus needing to re-reference the axis. Your softlimits if set correctly will give you the max available travel of your axis and will prevent you from moving further and triggering a physical limit switch, so in effect gives you a safe working envelope of your full axis travel..
The numbers in your softlimits are in Machine Coordinates, I think you may be getting confused with the work coordinate usually showing in your DROs. What I mean is once referenced you could move positive by 100mm on the X and then  zero the axis, it would now show up as 0. If you now  moved back towards your limit by 99mm it would show as -99 in the DRO. However if you toggle the Machine Coords button you will now see that the DRO reads 1 and so is still above the 0 setting in your softlimits. If you tried to move to -101 Mach would stop you as you would be going outwith the softlimits.

I am not the best at explaining so I hope this makes things clearer.

Hood
« Last Edit: December 31, 2007, 12:01:21 PM by Hood »
Re: Estop at wrong times web cam how do i ? help
« Reply #18 on: December 31, 2007, 12:54:55 PM »
Hi  Hood 
 yes  i  realise  we  are  talking Machine Coordinates, 
as  i  say  having  now  realised  that  the system  when  finished  reff  on  an  axis   that  the  soft  limits  become active again  then  it  is  obvious  that  it  has  to  be  a  0  as  this  is  what  we  are setting  the Machine Coordinates, to  once  referenced with  the  auto  zero function

mind  you  a  good  lesson  in  editing  code  to  make  it  do  what  you  want  .

now  i  just  have  to  find  out  why   the  estop  trips  when  i  load  wizards  and  when  they  save  g code  back  to mach 3
i  did  think  it  was  just  the  nfg wizards  but  now  found  that  all do  the  same 

think  i  need  to  look  at the  watchdog  signal  sent  to  the  break out  board see  if  that  stops  when  saving  the  data

thanks  for  you  help   bill