Setting up picLaser and j Tech DAC PWM

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cstmwrks
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Setting up picLaser and j Tech DAC PWM

Postby cstmwrks » Fri Nov 25, 2016 7:55 pm

Today my DAC board showed up. After reading the manual and working with PicLaser to some degree I think I understand enough of what is going on to do my machine set up.

So to make things clear, the J tech DAC uses step and direction info from a SPARE axis, correct? So right now I have the normal X,Y,Z + a slave to X as 2 motors run the carriage back and forth on the X axis. Lets say I have a spare called A. From within MACH 3 config i can set up the ports and pin outs to my BOB so step and direction info for axis A will go to the inputs on the DAC.

When setting up PicLaser in the input box labeled LASER CONTROL COMMAND would have the letter A entered as that is the axis the step and direction info goes to.

if this is right then I'm looking at connecting 2 more wires to be able to burn images.

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Picengravertoo
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Re: Setting up picLaser and j Tech DAC PWM

Postby Picengravertoo » Sat Nov 26, 2016 8:43 am

Yes, when using Mach3 and the DAC, you use a spare axis. I use the A axis because the Mach3 screenset has a DRO & jogging keys for it by default. In Gen Config, set the A axis as linear.

In PicLaser, use the Std, Gcode engraving profile and the Laser Control Command will be A. The Laser off Command should be A0. PicLaser will automatically add the M03/M05. Add a G90 G64 in the precode and G61 in the postcode.

In Motor Tuning use 10000 for inch or 393.7 for metric in the steps per. Set the Velocity & Accels as high as possible without loosing any steps. The step & dir pulse should be set to 3 for the DAC to work properly.

For the Max Laser Value, use a -.0255 for inch or a -.6477 for Metric.

Jeff

cstmwrks
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Re: Setting up picLaser and j Tech DAC PWM

Postby cstmwrks » Sat Nov 26, 2016 12:37 pm

Thanks. i just checked my config files and have some issues to sort out. One is that A and B are already enabled. not sure why as I only have 4 motors plus the spindle.

If for some odd reason that I don't know about yet, C axis will work?

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Re: Setting up picLaser and j Tech DAC PWM

Postby Picengravertoo » Sat Nov 26, 2016 12:48 pm

Yes, A, B or C will work, but unless you have a special screenset, it's hard to see what is going on with the DAC axis moves without a DRO to monitor it.

cstmwrks
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Re: Setting up picLaser and j Tech DAC PWM

Postby cstmwrks » Sat Nov 26, 2016 1:09 pm

i just figured out that even though A was enabled it was not connected to a motor. I just changed the ports so it goes to my BOB and have pin 14 and 16 for step and direction. I think A was pre set for a rotary chuck that I don't have.

cstmwrks
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Re: Setting up picLaser and j Tech DAC PWM

Postby cstmwrks » Sat Nov 26, 2016 10:46 pm

Picengravertoo wrote: Set the Velocity & Accels as high as possible without loosing any steps. The step & dir pulse should be set to 3 for the DAC to work properly.
Jeff


I think I have all the MACH 3 set up done. Just changed the profile back to using M03 per the info at the top here: http://jtechphotonics.com/?page_id=1436

After setting the steps per to 10000 I see the motor graph looked a little flat. Any ball park idea to set Velocity & Accels to? I know every machine is different but wondered if there was a ideal start point?

Thanks for all the help.

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Re: Setting up picLaser and j Tech DAC PWM

Postby Picengravertoo » Sat Nov 26, 2016 11:23 pm

It depends on your X&Y axis Velocity & Accels and what your machine can handle without loosing any steps.

I had to go through experimenting with those settings on my two Mach3 machines and they were different from each other. One has the Velocity set at 225 with the Accels at 125. The other has a Velocity set at 80 and the Accels are 100. You will just have to do the same experimenting with your machine. Try to keep all the axis's Velocity & Accels the same.

Raster engraving photos with a laser requires increased performance with smoother movement then cutting with a spindle. Any hesitations will cause burn spots in your photo engraving.

cstmwrks
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Re: Setting up picLaser and j Tech DAC PWM

Postby cstmwrks » Sun Nov 27, 2016 8:19 am

Picengravertoo wrote: Try to keep all the axis's Velocity & Accels the same.



Right now all the motor axis are set to 198.99 and 15 on acceleration. I'll test it and see how it goes. As is, when I burn line art the only time I get hot spots is on places with node clusters I did not bother to clean up.

Question on the A axis. Steps per are now changed to 10000. Being that this axis is not driving a motor anymore, does the velocity and acceleration setting have any effect on the laser getting the information it needs? Or do you mean ALL axis should be set the same regardless driving a motor or the laser?

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Re: Setting up picLaser and j Tech DAC PWM

Postby Picengravertoo » Sun Nov 27, 2016 9:14 am

Consider the laser DAC as a stepper motor driver because it takes the same step & direction signals. Mach3 has no way to know what the step & dir pins are attached to. It's just another axis. When your running gcode lines with X,Y & A moves, the slowest set axis will effect the faster ones so it effects the overall blended feedrate. With short step ahead moves when raster engraving you need to Accell/De-Accel fast through these short incremental moves so the movements don't hesitate/dwell. Make sure you activate Constant Velocity with the G64 command also.

If you have the X&Y axis accels set to 15 and the DAC at 100, the accelerations will run with 15 for all of the axis's including the DAC. If you have the Velocity for the X&Y axis's set at 198.99 and the DAC at 80, then it will only run at a 80 blended feedrate. A 15 Accel setting is way too low and that would cause excessive dwelling and burnt spots, especially where there are abrupt shade changes from one move to the next.

Experiment with the settings!!

cstmwrks
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Re: Setting up picLaser and j Tech DAC PWM

Postby cstmwrks » Sun Nov 27, 2016 9:35 am

Picengravertoo wrote:Consider the laser DAC as a stepper motor driver because it takes the same step & direction signals. Mach3 has no way to know what the step & dir pins are attached to. It's just another axis. When your running gcode lines with X,Y & A moves, the slowest set axis will effect the faster ones so it effects the overall blended feedrate.


OK that helped clear things up. Thanks


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