Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: BobsShop on September 02, 2006, 09:36:37 AM
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Running ver. 1.90.081. Keep getting "Softlimits may be exceeded -" message when loading files - even when the workpiece will be well within the edges of table and mill head extremes. Not a real problem, just a hassle to have to keep clicking the "Continue," button.
Should this feature take workpiece measurements, supposed table position, and limits into consideration? Or, is the warning called everytime a new G-code file is loaded?
Thanks
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This is being looked at and I there should be a fix in the next version or so...
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Brian,
V2.62 here.
Having this same issue.
Find anything ?
Thanks,
RC
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RC
that problem was solved long ago, you shouldnt be getting it now. Does it happen with most files or just specific ones? Which axis is it reporting as out of limits, you should see that in the ticker error box.
Hood
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Hello Hood,
I just finally set up the soft limits and slow zones. It works perfectly when jogging.
The file is a compilation of 2 wizards with some hand coding....nothing fancy. This is the only one I've run since setting up the limits, I'll try some others later. It reports the X axis (Turn). I have the home/limit sw. at the extreme X-. Soft limits are X.2 to X7. The entire part program is in the area of X2 to X5.
It appears to be comparing soft limits to part coords in X...Z is OK.
Thanks,
RC
The Z axis is checked "Reversed" and "Home Negative".
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Sounds like you may have the soft limits set wrong. You say X- extreme for your limit switch, is this beyond the centre of the spindle?
Hood
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Hood,
Yes, I just mounted the home/limit switch at the x neg. end of it's travel. And in homing selected Home Neg. That works OK. I think the manual says either way is OK.
The Z switch is at Z pos. end.
So every thing will be X+ (soft limits X+0.2 to X+6.0) and Z- (Soft limits Z-0.2 to Z-2.8 )
For X, I had "Dir Low active" checked and X "Reversed" checked in Homing/ Limits.
They are now both unchecked. No difference. Like one reverses the other...anyway.
After loading several files, the x / y limit DRO's on the run screen don't resemble anything similar to the code.. machine OR part coords.
Both Z and X have + and - values. Are they supposed to be in Machine or Part coords ?
Everything else works perfectly...referencing, homing, jogging, slow zones to soft limits in all 4 directions.
R2.60 is in that particular lathe. Is that too old maybe ?
I guess what's weird is after clicking to resume, NO soft limits are tripped...ever.
Thanks Hood,
RC
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The softlimits are in machine coords so you if your X home is at the X minus extreme your soft min should be Zero and your soft max should be the travel of your axis.
Do you have a way of repeating your tools when changing them? ie do you have a turret or QC toolpost or even stops for the tools going against.
If you do then you really want to set up a home off so that when you reference your X it will give its position in relation to the X axis. Then you can set up the rest of your tools in relation to your master tool. That means no matter which tool you have when your programme to turn a dia it will be that dia.
Hood
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OK so do a wee test for me, have your Soft Limits active and do a home, you should get an error message saying you are outwith softlimits or similar. This is because when homed you are on 0 and you have your softlimits set as 0.2.
Does this happen?
Hood
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Yes Hood, That does happen...as I believe it should.
The docs. describe the Soft limits being set off of the switches a bit.. (to be sure they are NOT hit) or where ever you like. Referencing ignores the Soft Limits and I turn them off to Home.
The tooling you mentioned is no problem right now.
The Problem is....
The Soft limits work perfectly when jogged to the extremes of each axis.
The ENTIRE Part program is WELL within this boundry and runs without a hitch ONLY after having to hit Continue at the Soft Limit Warning.
Thanks,RC
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Hey RC, they way it should work is this, I can leave my softlimits on, do a ref all home, and my soft limits will never let me hit a limit switch. Sometimes when I do a power up, I will have to disable my softlimits, ref all home the first time, enable softlimits. After this, it is good to go. The reason you can set your softlimit min to 0 is this, when you home the axis it goes till it sees the switch then reverses untill it isn't made. This is Machine 0. Softmin 0 will work here to because remember, it is not making your limit at this point. I don't understand why you get the warning if it is within the limits unless you have not done a ref. all before setting your coord. zeros.
Brett
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Thanks Brett, I've got a pretty good grip on that and understand the internal mechanism of a "Snap Action" limit switch. The Slow Zone prevents the overtravel that might trip the switch AFTER the DRO reaches 0.0000. But I don't think that is affecting my problem.
Let me ask this...
Is Soft Limit Min. the Mach. coord in the NEGATIVE most direction of travel ? Beit a + or - value ?
And " MAX " POSITIVE ? "
For instance...A lathe with Z 0.0000 at the right end, 10" to the chuck.
Z MIN = -10 Z MAX = 0 or vice versa ?
Thanks Brett,
RC
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Well I dont know where that is in the manual but if it is I disagree. The screenshot you have mentions the slow zone and not to have that too small in case the limits are hit.
Heres how I see things, when you home the machine trips the switch, Mach reverses the axis until the switch is again closed then stops, you are now referenced and your position is machine zero. If you set your min to zero it will be when the switch is closed. Now on to what I think the manual says, if you set a slow zone that is too close to the switch and you are moving towards the switch at full rapid Mach does not have enough time to decel the axis before it can reaches the limit switch and overshoots, thus tripping your switch.
This may wel be nothing to do with your problem but it is as well to get this sorted out as it will take one problem out of the equation and we can then move on to other possible causes.
Can you post the code and I will load the same version and see if I can replicate it.
Hood
EDIT
Sorry didnt notice this went on to page 2 and Brett has already described what I have said.
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Thanks Hood,
Can you find what I may be doing wrong in this example............?
Load the tap. file attached.
Set Home, X and Z , Machine Coords DRO's are 0.0000
Jog X in the POS. direction to 6.0 +/- (remember, my switch is at the X NEG. end of travel) Max travel is 12 in Dia. mode.
Jog Z in the NEG. direction to -6.0 +/- (Z-8.0 will hit the chuck)
Now, Zero the DRO's......Part Zero Verify by selecting Program coords. All are 0.0
Set Soft limits...X Max 12 Min 0.0
Z Max 0.0 Min -8.0
Hit Cycle Start and see what you get.
Thanks for helping Hood,
RC
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RC,
Things are fine for me, I tried it just setting up a new profile and dont get any errors. Could you attach your xml and I can load that and see what happens.
Hood
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Here you go.....Thanks Hood,
RC
My Lord....what a mess of chicken scratch. Good luck ! :D
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I just looked at your xml, you dont have any home switches defined in the Ports and Pins , Inputs. Is that the correct xml?
Also just re-read your earlier post and you are saying
Jog X in the POS. direction to 6.0 +/- (remember, my switch is at the X NEG. end of travel) Max travel is 12 in Dia. mode.
Jog Z in the NEG. direction to -6.0 +/- (Z-8.0 will hit the chuck)
Now, Zero the DRO's......Part Zero Verify by selecting Program coords. All are 0.0
Dont think you should be zeroing your X, your x axis should be at zero when the tool is exactly in line with the spindle centre. So it will depend on how you are setting your tools up how set this. If you dont have a way of accurately swapping tools (QC toolpost, Indexable ToolPost etc) then what you will need to do is take a skim cut on the dia of your stock, keep the X axis on this dia and measure the stock then enter this Dia into the DRO. What you are doing at the moment is saying that the zero position of the X axis is on the outside of the stock and you are turning it down into minus nimbers. Or am I reading this totally wrong?
Think I need to get a grip on where your limits are, which direction you are calling X plus and minus and Z plus and minus.
Is the following correct?
Your X axis is going negative as it moves towards the spindle centre.
Your X axis home is beyond the spindle centre in the X Negative direction.
Your Z axis is going negative when it is moving towards the chuck .
Your Z axis home is towards the tailstock.
Also do you have a way of accurately swapping tools such as a QC post or are you going to just set up each tool as you go into a programme?
Hood
PS out of curiosity what kind of motors are you using, it seems to be a fast beast, nearly 19M/min rapids
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Hello Hood, You asked........
Think I need to get a grip on where your limits are, which direction you are calling X plus and minus and Z plus and minus.
Is the following correct?
Your X axis is going negative as it moves towards the spindle centre. YES
Your X axis home is beyond the spindle centre in the X Negative direction. YES "X Home Neg."
Your Z axis is going negative when it is moving towards the chuck . YES
Your Z axis home is towards the tailstock. YES "Z Home Pos."
I am simulating this for you from my home PC, that's why you don't see the switches.
There is a single 3/16" square HSS tool mounted on the tool plate in a block.
I typically do the skim cut on the OD then measure the stock to set the Part X 0.0000 on center line of spindle. Also skim the face for Z 0.0000.
I have to set the tool up each time...that's OK for now.
For this example, moving x to anywhere near 6 and zeroing, puts Part X0.000 nearly in the center of the axis travel and near center of the set Soft limits for X which is 0.0 to +12.
Likewise for Z but Part Z 0.00 is about 2" from the chuck and the Z- soft limit.
The part is quite small and the program run doesn't come NEAR the Soft limits. So... why the warning ?
Could RADIUS/DIAMETER mode maybe have something to do with it ?
Thanks for taking the time Hood.
The simulating explains the motor speed.
RC
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OK I just set up the pins for the homes and set up a emulated key so I can simulate a home ( I too am on the home comp :) )
Funny thing is I am getting a Soft warning on Z min.
It quite hard trying to work out whats happeneing when you dont have the machine hooked up but I will see if I can work out why.
Strange that we are getting different axis warnings
Hood
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Earlier.....when I'd get a warning I kept increasing the SL hoping the warning would go away. It then shifted to the OTHER axis ! After several incremental increases it FINALLY went away but then the SL's were bigger than my entire machine ......well nearly.
It works so WONDERFULLY in Mill.
I'm leaning towards the Rad./ Dia. mode.
Thanks Hood,
RC
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OK so what you are saying is your X axis when referenced is 3 inch past the spindle centre so that would be minus 6 in Dia mode. You then go to 6 in Dia mode and that puts your tool on spindle centre so you zero the axis. OK so if thats correct what you want to do is this, go to homeing and limits and enter -6 for Home Off on the X. Next reference your machine and the DRO should read -6 for the X when homed and looking at machine coords. Go back to normal coords and enter -6 into the DRO. Now when you command a G0X0 your tool should be on spindle centre. I have just tried this and it seems to stop the limits warnings.
The home off is the usual way to set up the X axis to put the tool on zero when homing.
Hood
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Yes, correct.
I did as you say and understand why but still have the problem.
If you would kindly do 1 more test for me, I will hang this up before I go totally nuts.
1. Load the tap.
2. Do as you have in your last post and while on normal coords enter +6 in the Z DRO.
3. Put the DRO's on "Machine" and leave them there.
4. Soft Limits OFF, go to Auto and run 1 part.
5. I then single stepped through the entire program and recorded the max and min moves in all 4 directions in "Machine" coords.
They were : X-2.75 Set the Soft Limits as in the attachment.
Z-6.5 Z-5.89
X-2.39
6. Turn Soft Limits ON and jog in all 4 dirs. to verify that they work perfectly as per the settings and extend WELL beyond the program.
7. Go to Cycle Start and if no WARNING pops up... I'll EAT MY HAT.
Just please let know what you find.......I may need to get some CATSUP !
Thanks Hood,
RC
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RC
When I wrote my last post it was after 1am here and I was making more cockups than I usually do. Looks like this is exactly the same thing that affected Mill. Mill was sorted out but looks like turn wasnt. I dont use softlimits on my lathe, there is no real point because with a front post, tailstock, rear post etc I could never configure the limits to be of any use, however I will give them a try and see what happens. Safe to say though your head is going to stay warm.
Hood
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So ....It is UNfixed.
Well....it's only 1 extra mouse click to shut-up the warning and continue as normal.
And they do work well when jogging and while the program is running.
Better than no limits at all.
Thanks much Hood,
Over and Out,
RC
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Yes, just set them up on my lathe, put in some code and yes I get Soft Limit on X min Warning. I will ask Brian to put it on his to do list but dont expect it will be near the top of the list as I think hes fairly busy:)
Hood
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No prob Hood,
I'm sure there are FAR higher priorities than this.
Thanks MUCH,
RC