Setting Up 4th Axis Configuration Help Needed
30 May 2013 12:29 #34944
by tomfool
Setting Up 4th Axis Configuration Help Needed was created by tomfool
As a Newbie to LinuxCNC I can sure use some help getting my machine up and running. The machine is a TIG seam welder.
I am using the X axis to move the tourch down the seam, the Z axis to position the tourch above the seam to maintain arc distance and the A axis to control a 2K variable resistor to control the voltage to drive the arc. I used the basic Stepconf
Wizard to build a four axis system to get started.
The welding machine, the actual power source, has a voltage limiting knob to set the maximum voltage. The variable resistor then can be adjusted from zero degrees to 359.99 degrees to change the voltage at the arc from zero to 100 percent of the full voltage set at the power source.
If the voltage limiting knob was set at 50V at the power source and the variable resistor was turned to 180 degrees the voltage at the arc should be 25V . Turning the resistor to 270 degrees and you should get 37.5V, 359.99 degrees for 50V.
I need to limit the physical rotation of the resistor to a bit less than 360 degrees to keep from breaking the internals of the device.
It would be nice to be able to scale the movement so that the part program could be set for A50 for 50% rather than A180 for 180 degrees but it's not a deal killer.
First I have to figure out how to configure the axis so it will only rotate between 0 and a bit less than 360 degrees.
Currently, I have the XZ axes physically working and have simulated a part program using the AXIS interface including the addition of the A axis. I have noticed when the simulation is run, if the A axis is run on a line by itself the change from say A80 to A100 takes a long time but if the same A axis movement is on the same line as an X axis movement, the two seem to be coordinated and end together.
When I get the A axis properly configured what can I expect in terms of positioning the resistor by itself and coordinated with the X axis?
If this is too much to ask in one posting, I'm sorry. Like I said at the beginning, this is my first attempt at this sort of thing.
I thank you all in advance for any help I may receive.
I am using the X axis to move the tourch down the seam, the Z axis to position the tourch above the seam to maintain arc distance and the A axis to control a 2K variable resistor to control the voltage to drive the arc. I used the basic Stepconf
Wizard to build a four axis system to get started.
The welding machine, the actual power source, has a voltage limiting knob to set the maximum voltage. The variable resistor then can be adjusted from zero degrees to 359.99 degrees to change the voltage at the arc from zero to 100 percent of the full voltage set at the power source.
If the voltage limiting knob was set at 50V at the power source and the variable resistor was turned to 180 degrees the voltage at the arc should be 25V . Turning the resistor to 270 degrees and you should get 37.5V, 359.99 degrees for 50V.
I need to limit the physical rotation of the resistor to a bit less than 360 degrees to keep from breaking the internals of the device.
It would be nice to be able to scale the movement so that the part program could be set for A50 for 50% rather than A180 for 180 degrees but it's not a deal killer.
First I have to figure out how to configure the axis so it will only rotate between 0 and a bit less than 360 degrees.
Currently, I have the XZ axes physically working and have simulated a part program using the AXIS interface including the addition of the A axis. I have noticed when the simulation is run, if the A axis is run on a line by itself the change from say A80 to A100 takes a long time but if the same A axis movement is on the same line as an X axis movement, the two seem to be coordinated and end together.
When I get the A axis properly configured what can I expect in terms of positioning the resistor by itself and coordinated with the X axis?
If this is too much to ask in one posting, I'm sorry. Like I said at the beginning, this is my first attempt at this sort of thing.
I thank you all in advance for any help I may receive.
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30 May 2013 18:59 #34963
by BigJohnT
Replied by BigJohnT on topic Setting Up 4th Axis Configuration Help Needed
The amount an axis moves depends on the scale. For example if you have 200 steps per revolution on your stepper and have 10 micro steps on your drive for each step on the stepper then it takes 2000 step pulses to go one revolution. If you want A50 to move 180 degrees(1000 steps) and 360 degrees = 2000 steps then you have to do the math to calculate the number of desired steps to take for A50.
When you move a rotary axis and no linear axis is moving use G93 mode . When linear axes and rotary axes are moving together then the planner moves the rotary at a speed to end up with the linear axes.
The rotary axis limits are set in the ini file, however for them to work you must home the axis at the same point each time you start LinuxCNC.
JT
When you move a rotary axis and no linear axis is moving use G93 mode . When linear axes and rotary axes are moving together then the planner moves the rotary at a speed to end up with the linear axes.
The rotary axis limits are set in the ini file, however for them to work you must home the axis at the same point each time you start LinuxCNC.
JT
The following user(s) said Thank You: tomfool
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26 Jun 2013 10:49 #36062
by subnoize
Replied by subnoize on topic Setting Up 4th Axis Configuration Help Needed
Hmmm, maybe I should have posted here instead!
I'm having trouble finding a CAM package that will drive my A axis correctly. Very frustrating since I have a great machine but no way to control it!
My other post is here; www.linuxcnc.org/index.php/english/forum...s-and-inverse-timing
I'm having trouble finding a CAM package that will drive my A axis correctly. Very frustrating since I have a great machine but no way to control it!
My other post is here; www.linuxcnc.org/index.php/english/forum...s-and-inverse-timing
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26 Jun 2013 21:39 #36081
by BigJohnT
Replied by BigJohnT on topic Setting Up 4th Axis Configuration Help Needed
It's not a good idea to hijack a thread as it confuses the search and makes the topic of threads hard to follow. I almost never reply to hijacked threads.
It's always better to start your own thread about your topic.
JT
It's always better to start your own thread about your topic.
JT
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