Hello Guest it is November 21, 2019, 04:02:28 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - brandstu

Pages: 1
1
I am not saying do it but just consider the following circuit…

The variable, inverted, PWM from Mach3 (controlled by the M3 S####) is fed into Opto1 and the output PWM is taken to ModIN on the BB8M.

This PWM signal will be…
ON when Output# is TTL Low
OFF when Output# is TTL High
(Opto2 will short the isolated ‘PWM out’ to GND).

So, in your Gcode PWM is turned on and the power level set with M3 S###
Output# (and thus the laser beam) is turned ON/OFF using the M11/M10 commands.

Just a thought.

Tweakie.


Just a quick update. This does not work as intended. I am not able to control the power. I think I was able to use M3/M5 anyways so that was what made me think that I fixed it. I didn't have time to test it earlier, it looks liked different laser powers but I am fairly certain it is not. Maybe I am not understanding your diagram fully. Any clarification would be greatly appreciated.

2
Also, ignore the ground wire. It shares a common ground across the device. It works! I just fed the PWM signal to the opto coupler and bam.
I can M3 the spindle on with what S requirement I need and it still responds to M10/M11 commands. I am getting some dots where vectors start however. I assume either my accel is low, or it is the ay I am creating the files in v-carve. It seems like it almost stops at certain places along some vectors.

I am starting to look at the PIC engrave software now. Thanks so much for the help Tweakie!

3
I am not saying do it but just consider the following circuit…

The variable, inverted, PWM from Mach3 (controlled by the M3 S####) is fed into Opto1 and the output PWM is taken to ModIN on the BB8M.

This PWM signal will be…
ON when Output# is TTL Low
OFF when Output# is TTL High
(Opto2 will short the isolated ‘PWM out’ to GND).

So, in your Gcode PWM is turned on and the power level set with M3 S###
Output# (and thus the laser beam) is turned ON/OFF using the M11/M10 commands.

Just a thought.

Tweakie.


Just to make sure I understand you correctly. I drew a diagram with the MX4660. It does have opto couplers available and the way it looks, I might just be able to use 1 and have it switch the output#1 off and on while still sending the PWM signal since the optocoupler has inputs available. [img][img]

4
Hi Brandstu,

Welcome.

Quote
The laser will not turn off during cuts and only turns off when it is finished with the job(M5), so you see the movement lines.

Assuming your set-up allows you to turn the laser ON with M03 and OFF with M05 this problem would generally be overcome within the post-processor you are using.
Feed-rate moves (G01,G02,G03) are cut/engrave so the laser is turned ON. Rapid moves (G00) are positioning so the laser is turned OFF.
So modify your post-processor to add an M03 before each feed-rate move and an M05 before every rapid move.

This system would work and at least it would get you started.

As you will soon discover, the M3/M5 commands are slow to operate so you really need to be using the M11/M10 command set to switch the laser beam ON/OFF. You may also find that switching the PWM ON/OFF is also too slow so you will almost cirtainly need additional circuitry to switch the ModIN on the BB8M between the PWM signal and GND.

Tweakie.


Also on your site I saw a circuit that I thought might be helpful. So turns out it works now. Well at least the M10P1 and M11P1, The power does not change now but it does turn on and off between moves. Figured out the output problem and it wasn't so much of a problem as it was an oversight on my part. I really need to be able to vary the power on the laser though so I need to find a way to hook output1 up to the pwm circuit to have it turn off and on.

5
Thank you very much for your reply Tweakie,
I have read through your site multiple times and many of your forums posts on this issue.

I understand that the speed using M3/M5 won't be acceptable for laser usage and the reason I am looking into the m10/m11.

So the MX4660 has a crazy amount of inputs and outputs. I am sure I can figure out a way to do whatever I need to in relation to switching the laser on and off rapidly with something already on board.

However I have an external power supply specifically for the laser which I think presents some of the problem.

What I am having trouble wrapping my head around is that I am using pin 14 for the pwm signal to the driver. The other wires do not have pins because one is gnd and the other is voltage reference.

I think since that is providing the signal for the variation in power and I can't reuse a pin in MACH, how do I tell pin 14 to switch on and off with output 1 (or output 2) without reusing the pin and creating a conflict.

So I am thinking I would need a relay to switch the power off and on, but having external power go through a controller that is already powered might not be the best idea. I do have an extra driver for my rotational axis I could unplug and it provides 12 VDC @ the correct amperage for the laser to the stepper motor so I wonder if I could somehow wire the laser directly to the stepper motor output to provide power and on and off while still using the pwm on the main controller to control the power level when it is on.

I also see what you are saying about the post processor. I actually have tried a few and am learning to modify them. I used yours as from your site. When editing a post processor on some instructions I see people saying that m10p1 is m10 pin1 and other saying port 1 and other saying output1. I am thinking its the output# but then you would need to assign a pin to that output I think, but I am not sure how to accomplish that in MACH3.

6
Hello,
I have a laser diode on a driver with PWM and that is hooked up to a MX4660. I use a parallel port.

I have my pin set for PWM #14 and I can control the on off of the laser with M3/M5. I can also control the power with the S commands inside MACH.

The laser will not turn off during cuts and only turns off when it is finished with the job(M5), so you see the movement lines.

I have tried Tweakies post processor to enable the M10 and M11 commands but I am not sure I have the correct pin out for output 1, I also do not have a screen in mach to enable those commands. I have checked under general config and mine looks different than the one of the Jtech site and CNCRP.

My CNC motor driver has PWM out built into it and uses pin 14. However I keep seeing someone saying something about an output so I am not really understanding how that flows.

If there is any more information that I can provide to help remedy this situation I would be grateful for any feedback.



Pages: 1