Problem- XYAB setup

[jodhner]

Hi all,

I trying to set up my new off the shelf Sherline CNC from it's XYZA configuration to an XYAB configuration.

The mill came with the standard sherline CD with Linux, EMC, the Mini GUI, and it runs fine as an XYZA machine.

I've tried to change the INI file from:
X 0 linear
Y 1 linear
Z 2 linear
A 3 rotary
to:
X 0 linear
Y 1 linear
A 2 rotary
B 3 rotary

The system doesn't start when I've made changes to the INI -- the popup pops up, then goes away without the Mini GUI opening. It seems like something doesn't like the changes I've made.

Do I have to mess with the HAL? Is it correct to map XYAB to 0123, or do I have to map XYAB to 0134, and mess with HAL settings?

Anyone have suggestions/solutions? I hope someone out there makes lots of axis configuration changes and knows exactly what to do . . . . .

[jmelson]

Originally Posted by jodhner Hi all, I trying to set up my new off the shelf Sherline CNC from it's XYZA configuration to an XYAB configuration. The mill came with the standard sherline CD with Linux, EMC, the Mini GUI, and it runs fine as an XYZA machine. I've tried to change the INI file from: X 0 linear Y 1 linear Z 2 linear A 3 rotary to: X 0 linear Y 1 linear A 2 rotary B 3 rotary The system doesn't start when I've made changes to the INI -- the popup pops up, then goes away without the Mini GUI opening. It seems like something doesn't like the changes I've made. Do I have to mess with the HAL? Is it correct to map XYAB to 0123, or do I have to map XYAB to 0134, and mess with HAL settings? Anyone have suggestions/solutions? I hope someone out there makes lots of axis configuration changes and knows exactly what to do . . . . .

OK, there are a couple things you need to do. The "missing" axes don't quite go away when you don't use them. So, to include the B axis, you need to tell EMC that it has 5 axes. The default axes then would be XYZAB. You are going to "skip" the Z axis. So, your TRAJ section would start like this :
[TRAJ]

AXES = 5
COORDINATES = X Y A B
HOME = 0 0 0 0
LINEAR_UNITS = inch
ANGULAR_UNITS = degree

You will also need to work on the section that maps the HAL pins to the specific motion driver to route the right axis signals for axes 0,1,3 and 4 to your first 4 motion output channels.

Jon

[samco]

I really should learn how to read!

Heinz Reimer just added surline configs to the development version of emc2

http://cvs.linuxcnc.org/cvs/emc2/configs/Sherline4Axis/

Should get you what you need.

sam

[jmelson]

Originally Posted by samco I really should learn how to read! Heinz Reimer just added surline configs to the development version of emc2 http://cvs.linuxcnc.org/cvs/emc2/configs/Sherline4Axis/ Should get you what you need. sam

But, he specifically wanted XY and AB, not the more common XYZ plus A. There is a difference there, as EMC2 computes voordinated velocities with XYZ all linear, and doesn't add AB rotations to the velocity calculation. The OP didn't make clear what he was doing with the XY AB, and whether he really intended the A and B as angular axes or was doing a foam cutter or wire EDM with A and B being the additional linear axes. Depending on what he is actually doing with it, it may or may not make a difference.

Jon

[jodhner]

"...The OP didn't make clear what he was doing with the XY AB..."

I've got a 2000 Sherline with X and Y doing their normal table duties, A will be driving a rotary table flat on the table, and B will be driving a rotary table mounted on the A table.

The most complicated thing I'll be doing is:

G2 Xxxx Yyyy Iiii Jjjj Aaaa Bbbb

My understanding is that G-code should coordinate the velocities of the A and B axes so their motions end when the G2/G3 motion ends.

btw: I'm cutting bevel gears with a flycutter. The spindle is positioned parallel to the X axis. The B table is on an angle table on the A table. This setup emulates a crown rack generating involute profile teeth.

Thanks,
--Justin

[jodhner]

Geometry disclaimer:
There are a couple of additional tweaks required for this gear forming method to be accurate.

[jodhner]

No apologies!
I'm currently using the Sherline distribution, which appears to be pre-HAL. So, I'll have to put things together from the standard distribution. The information you referenced will give me a good baseline.
Thanks.

[jmelson]

Originally Posted by jodhner No apologies! I'm currently using the Sherline distribution, which appears to be pre-HAL. So, I'll have to put things together from the standard distribution. The information you referenced will give me a good baseline. Thanks.

OK, then I think you really need a complete update of both the OS and EMC2 to be able to skip axes and have some of the other features you want. Also, the Axis preview should actually show what the machine will do. (You may have to make some adjustments to a setup file for Axis to get the rotary axes to display in the right sense.)

Jon

[jodhner]

I've upgraded to EMC2 and got it working with my Sherline mill using the standard XYZA configuration. I used the stepper configuration wizard. Everything seems fine. (I've been working with the Sherline Stepper Driver's developer on the correct stepper timings and will report specifics soon.)

Now, when I edit the .ini and .hal, to to change over to the XYAB configuration with two rotary tables, which is the whole point of this exercise, the Axis GUI window never comes up, and the loader exits.

I've attached the terminal screen contents, and the .ini and .hal files.

Anyone see what I did wrong ? I've marked my editings of the wizard generated files with a streak of asterisks.

Thanks,
--Justin

[samco]

I would get on IRC if this doesn't help..


http://www.linuxcnc.org/component/op...emid,8/lang,en

parameter or pin 'stepgen.4.position-scale' not found
he needs to number AXIS_0, AXIS_1, AXIS_2 and AXIS_3
and loadrt stepgen step_type=0,0,0,0 -> causes stepgend 0,1,2,3 to appear

[jodhner]

I have the X, Y, A, B Axes mapping to the 0, 1, 3, 4 axis data structures, and the 0, 1, 3, 4 axis data structures mapping to the 0, 1, 2, 3 stepgen data structures. I can jog XYAB now.

So simple my dead cat could have done it.

Now I'll get to work on the stepper timing parameters for the Sherline Stepper Driver . . .

Thanks people.

[chester88]

Originally Posted by jodhner (I've been working with the Sherline Stepper Driver's developer on the correct stepper timings and will report specifics soon.) --Justin

It seems that there were a lot of different timing depending on the when the driver was built. If you can get reliable numbers we will add them to the next version of stepconf.

Chris M