Messages

1

General Mach Discussion / Re: Laser control on and off using Z

« on: March 02, 2017, 03:51:33 AM »

I asked everyone and you were the only one who confirmed that the output should be persistent.
I could not think of a solution without knowing that before.
Thank you very much Tweakie!

2

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 01:07:52 PM »

Well, I finally used a flip-flop (555) triggered by DIR of the A and Z axes (One to turn on the laser and the other to turn it off).
I do not know if there is an easier way (tell me), but for now these axes are available and I will use them that way.

3

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 08:50:48 AM »

In fact, the outputs of the axes do not maintain the level 

4

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 02:33:51 AM »

Thanks for your help Tweakie.
I'll do it as soon as I get home.
I think we know what's going to happen. Unlike a parallel BOB, the DIR signal will not be persistent and apparently this does not affect Mach3.
What I am going to do? 

5

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 02:24:23 AM »

Wait, please completely rule out a power supply fault.
Now I remember that at the recommendation of the seller of the laser, the only thing I'm doing with the relay is to join TTL- with TTL +, there is no need to send any level of voltage if it is working at all-nothing.

6

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 02:20:19 AM »

I'm at work right now, but I will.
However, as I said above, using the same ATX power supply and the outputs activated with M3 and M5, I had no problems. So I do not think the problem are the 5V.

7

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 02:15:24 AM »

One more thing. The outputs work properly, I mean, their signals are persistent (M3) until I turn them off (M5), I have used them for the laser but there was an unwanted response time, so my interest in using one of the axes (as everyone, I think).

8

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 02:04:56 AM »

I'll try...

But I think that if the signal must be persistent, there must be the problem ...
My BOB is this (due to my laptop, I can not use the parallel port for a traditional one):

https://www.aliexpress.com/item/Factory-outlets-100KHz-CNC-mach3-USB-4-Axis-Stepper-Motor-Driver-Breakout-Board-USBCNC-Smooth-Stepper/32334451366.html?spm=2114.13010608.0.0.cJRtzN

Mi laser:

https://www.aliexpress.com/item/Focusable-450nm-2W-Laser-Engraver-445nm-2000mW-Blue-Laser-Diode-Module-with-TTL-for-CNC-Engrave/32745647304.html?spm=2114.13010608.0.0.bcOG86

The laser takes 12V from an ATX power supply.
To excite the TTL input of the laser, I am connecting a relay between + 5V and DIR- on my BOB (DIR- of Z & A axis, I have tried both).
This relay connects 5V from the same ATX power supply and sends them to the TTL input.

But beyond this connection, now I understand that the DIR signal must be persistent as you say (If I do not want to use some kind of monostable or flip-flop).
I have not measured the DIR-voltage changes, but I assume it will be almost imperceptible in my digital tester.
What I'm wondering is: is it possible that this USB BOB works differently than a traditional BOB via parallel port?
Would it affect Mach3 at all if the DIR signal is not persistent?
From what I could see when setting high values on the Z axis when the laser is turned on, it stays on during the travel of this axis. That's why there is only a flash when I want to activate it quickly.

What do you think?

9

General Mach Discussion / Re: Laser control on and off using Z

« on: March 01, 2017, 12:05:06 AM »

For your Z axis if you measure the voltage between +5v (Dir+) and Dir- it will change between 0v and 5v depending on which direction the axis was last moved.
Connecting a relay directly may not be a good idea (the Dir- can only sink 50mA current and it is already driving the Z axis controller) so use an opto coupler (or similar device) to drive your relay from the +5v and Dir- terminals.

Tweakie.

Hi Tweakie.
I just asked this a moment ago, but on a very old thread. I think it's more appropriate to do it here, I hope you can help me.
Could you tell me why when I use this method, the laser stays on only a flash? The laser does not stay on for the entire path, only turns on for an instant.

10

General Mach Discussion / Re: How do i setup Mach3 to control a laser with TTL input?

« on: February 28, 2017, 11:56:07 PM »

Hi Borge,
The laser TTL spec is usually <0.5volts for off and >2.0 for on. Providing it does not draw any appreciable current this input can be connected to the Z axis direction pin  on the BOB so that it turns the laser on for -Z moves and off for +Z moves. I disable the Z axis so that the laser focus is not disturbed and use the Z axis DRO scale factor to control the 'laser bite time' (which varies from material to material). If the laser operation is reversed then change the direction active low under ports and pins.
Although I have used this method quite successfully I now favour a simple shutter system to switch the laser beam on and off, again using the Z axis direction signal as I believe that longer laser life will be achieved by using a soft start when it is turned on from cold.

Tweakie.

There is some further information here :-

http://www.cooperman.talktalk.net/index_files/Page4549.htm

Hi Tweakie.CNC
Could you or anyone else tell me why when I use this method, the laser stays on only a flash? The laser does not stay on for the entire path, only turns on for an instant. Do you use some kind of monostable to deal with this?