Multiple profiles or homing question

[guerra_cues]

Hello,
Wondering if there is a way to have multiple profiles on CNC12.
I will explain, maybe there is a workaround.
There is a particular task that I need to do that requires me to make a cut, glue my inlay and stay on the exact same spot without loosing a thousand of an inch.
Is there a way to stay on that spot, turn off the machine, turn it on the next day and start cutting again from the exact same spot without loosing my position?
Here is a video of the cut I’m doing and when it’s done, it needs to stay there.

[cnckeith]

yes, accurate homing is how that is done. the more accurate the homing setup the more accurate the part position is held after power on/off.
two options

1.) use "home to marker pulse" (aka ZRi homing) is the most accurate way to setup homing on any Acorn equipped machine tool. but not alot of axis motor drives offer the index pulse (aka marker pulse)

2.) use "Auto Home to switch" and use accurate home switches.

when homing is setup and working CNC12 "remembers" all the work coordinate positions after a power cycle, so you can shut the machine down and then come back a week later and pick right back up where you left off.

[guerra_cues]

yes, accurate homing is how that is done. the more accurate the homing setup the more accurate the part position is held after power on/off.
two options

1.) use "home to marker pulse" (aka ZRi homing) is the most accurate way to setup homing on any Acorn equipped machine tool. but not alot of axis motor drives offer the index pulse (aka marker pulse)

2.) use "Auto Home to switch" and use accurate home switches.

when homing is setup and working CNC12 "remembers" all the work coordinate positions after a power cycle, so you can shut the machine down and then come back a week later and pick right back up where you left off.

Hello Keith,
Thanks for the reply. On home to marker pulse I have Clearpath motors so I’m not sure if they support that or go about it…
Auto home is not the same as park?
One thing I noticed is that I have to move the CNC like 0.010 or 0.100” and then set home when I turn everything on, if I hit cycle start the CNC does not home it errors out.

[cncsnw]

If accurate homing is impossible with your machine and control, and if you are good with math and keyboards, and you can somehow ensure that the axes do not move at all while the power is off, then you can do what you are asking for with M26 at the MDI prompt.

Before shutting down, switch the DRO to Machine Coordinates with Alt-D.
Note all the axis positions, in Machine Coordinates.
Multiply each position by the counts (pulses) per inch value for each axis, to get the axis absolute position in pulses.
Alternately, you can go to the PID Configuration screen and look up the "Abs Pos" value for each axis.
When you next power up, instead of pressing Cycle Start to find home, press F3 for MDI.
For each axis, use M26 with the "L" option to set the current position to the previously-recorded absolution position.
For example, to set Machine Zero on the X axis so that the current X axis position becomes -123456 pulses, enter:

Code: Select all

M26/X L-123456

Do that for each axis, and machine home will be set.

Of course, if your axes move a few thousandths when you turn power off, then all bets are off.

[cncsnw]

No, Home is not the same as Park.

Home moves onto, and off of, each limit switch, then sets Machine Zero at the clear-of-switch position.

Park moves each axis just short of the previously-found Machine Zero position, so that the next homing cycle will not take very long.

At least on closed-loop controls (Oak, Allin1DC, MPU11, CPU10, CPU7 etc.) there is a deliberate offset (1/4 of a motor turn) in the Park position, so that finding home is guaranteed to find the correct home even if it is locating an index pulse without the benefit of switches. I suspect that the same 1/4-turn offset is present on Acorn, but you would have to try it to find out for sure.

[cnckeith]

fyi...Park with acorn can be controlled with user created macro, so it can do what every you want:-))

from the Wizard..

[guerra_cues]

I am a bit confused then, what is the proper way to home the CNC once you are done working or once you start working?

[ShawnM]

You have to home the machine at every start up BEFORE you start anything. Either "simple home" or "home to switches", there's no way around this. You can shut down the machine at any time without parking or moving or rehoming the gantry. Just shut down at anytime anywhere. Next time you power it up you'll have to home that machine again.

It sounds like you don't have your homing setup properly or you don't fully understand how it works. I'm confused by your comment "One thing I noticed is that I have to move the CNC like 0.010 or 0.100” and then set home when I turn everything on, if I hit cycle start the CNC does not home it errors out." What do you mean it errors out? Do you have a screen shot?

A standard start up procedure would be-

- turn on the pc so it starts to boot up
- turn on the machine control aka your Acorn (doesn't matter the order, Acorn then pc if you like)
- after the pc boots and you have a heartbeat on the Acorn launch CNC12
- software opens and the message window reads "9033 Reset Initiated, press reset to clear"
- press the reset button and the message window now reads "4032 reset cleared"
- at this time you must press cycle start to home the machine, it'll either simple home to it's current position or home to the switches but either way it'll home and the DRO will then read all zeros.

Now the machine is homed and ready for you to tell it what to do. This procedure is the exact same at every start up. As stated earlier, you can close CNC12 and power down the machine with the gantry in any position. You dont have to park it or move it or do anything special.

What is your procedure? What errors are you getting?

[cnckeith]

install home switch on each axis at the end of the travel for that axis = machine zero position, aka "home"
i like to install them in series and wire to one input and assign the input as "HomeAll" in the wizard.
select Auto Home in the wizard which will generate a home program that will seek each switch individually during the homing cycle.
once each switch has been triggered and cleared each axis is at the home position and cnc12 sets machine zero position at that point.
part zero locations are relative to machine home. so if the homing cycle is consistent (meaning if you home the machine it always reaches the same point when done) the part zero locations are retained.

note: parking the machine is completely optional and has nothing to do with remembering the part zero locations (g54,55,56,57,58,59 etc) park is just a convenience feature to pre position the machine before powering off so that when you power it back on the machine does not have far to travel to reach the home switches, it is just a time saving feature thats all.

[guerra_cues]

install home switch on each axis at the end of the travel for that axis = machine zero position, aka "home"
i like to install them in series and wire to one input and assign the input as "HomeAll" in the wizard.
select Auto Home in the wizard which will generate a home program that will seek each switch individually during the homing cycle.
once each switch has been triggered and cleared each axis is at the home position and cnc12 sets machine zero position at that point.
part zero locations are relative to machine home. so if the homing cycle is consistent (meaning if you home the machine it always reaches the same point when done) the part zero locations are retained.

note: parking the machine is completely optional and has nothing to do with remembering the part zero locations (g54,55,56,57,58,59 etc) park is just a convenience feature to pre position the machine before powering off so that when you power it back on the machine does not have far to travel to reach the home switches, it is just a time saving feature thats all.

Hello Keith,
Each switch has it own input, so my switches are not in series and they are not mechanical, so they are pretty accurate.
The homing file has been customized so it does not try to zero the A axis since I don’t have a switch installed on it.
I just have a particular task that I would like not to move out from when I’m done cutting a pocket with a 90 degree cutter like I’m showing in the video.
When doing that task I’m tempted to change from automatic seek home to manual and that way I can home the machine on that spot. I can always change that to home automatically when I am done with that task. Do you think that it is a valid workaround?