Delay between start button and the actual job start?

[MitchL]

I'm using the OUTPUT1 signal to start the exhaust fan on my laser, but the job starts too quickly for the fan to come up to speed (and the air assist compressor for that matter).

Has anyone used or experimented with the footswitch control input (INPUT2?) I have a microcontroller on my laser that is connected to the fans, the inputs and outputs, etc., so I was about to experiment with the following:

- When you press START, the OUTPUT1 signal goes high.
- The microcontroller will immediately turn on the exhaust fan, _AND_ press and hold the "footswitch" (INPUT2).
- Microcontroller waits for the fan to come up to speed
- Microcontroller releases the footswitch (INPUT2)
- Job runs, eventually it completes (OUTPUT1 goes low)
- Microcontroller runs the exhaust a little longer, then turns it off.

I find that the footswitch is a multi-purpose input. It also *starts* jobs (works like the start button). I will need to experiment some more, but it would certainly (to me, anyway) be a good feature for the AWC to have a programmable delay between OUTPUT1 activating and the actual laser job.

The other option I have is to have the microcontroller start the job using the footswitch control, then I can do all the sequencing there. I'd prefer to use the start button on the AWC's keypad though.

/Mitch.

[swamidog]

i use the OUT1 on 2.OUT to trigger a relay and start the air assist compressor whenever the table is in motion. that way there's no timing issues between the air starting and the laser firing.

it is very fast, also i just turn the exhaust fan on when powering my cutter. it's quiet and it's better on the machinery to keep it running than subject it to rapid power cycling.

air-wire.jpg (137.05 KiB) Viewed 2765 times

http://youtu.be/UsXl6g_FYa4

I'm using the OUTPUT1 signal to start the exhaust fan on my laser, but the job starts too quickly for the fan to come up to speed (and the air assist compressor for that matter).

Has anyone used or experimented with the footswitch control input (INPUT2?) I have a microcontroller on my laser that is connected to the fans, the inputs and outputs, etc., so I was about to experiment with the following:

- When you press START, the OUTPUT1 signal goes high.
- The microcontroller will immediately turn on the exhaust fan, _AND_ press and hold the "footswitch" (INPUT2).
- Microcontroller waits for the fan to come up to speed
- Microcontroller releases the footswitch (INPUT2)
- Job runs, eventually it completes (OUTPUT1 goes low)
- Microcontroller runs the exhaust a little longer, then turns it off.

I find that the footswitch is a multi-purpose input. It also *starts* jobs (works like the start button). I will need to experiment some more, but it would certainly (to me, anyway) be a good feature for the AWC to have a programmable delay between OUTPUT1 activating and the actual laser job.

The other option I have is to have the microcontroller start the job using the footswitch control, then I can do all the sequencing there. I'd prefer to use the start button on the AWC's keypad though.

/Mitch.

[MitchL]

Hi Swamidog,

Thanks for your reply -- my setup is similar to yours - I have the OUT1 and OUT2 (and IN1, IN2, the laser WP signal, and others) running to a micro controller, which is in turn connected to relays that run out to the exhaust, air assist, etc. I can program the behavior to be anything I need. So, I have relays, just not directly connected.

I'm ok cycling the exhaust fan, I'll happily exchange the extra wear on the fan for some peace and quiet in the shop while I set up a job.

If I can't get the delay start to work, I can just add a button on the micro controller to turn the exhaust on manually before a job (and I can still turn it _off_ automatically).

See: https://www.youtube.com/watch?v=nyGHMwixa-4 -- The laser is unfinished, I'm just getting things working now.

In the end, I want to use OUT1 to detect job start/stop. When the job starts, both the Exhaust and the Air Assist turn on. At the end of the job, I stop the air assist, wait for the air to turn over a couple of times in the laser, then turn off the exhaust.

The OUT2 signal will be used to calculate the laser-firing hours for the tube.

/Mitch.

[swamidog]

what a nice build you have! i'm started constructing the framework kit, but some other projects have been consuming my time.

you'll be making beautiful things with your machine soon.

Hi Swamidog,

Thanks for your reply -- my setup is similar to yours - I have the OUT1 and OUT2 (and IN1, IN2, the laser WP signal, and others) running to a micro controller, which is in turn connected to relays that run out to the exhaust, air assist, etc. I can program the behavior to be anything I need. So, I have relays, just not directly connected.

I'm ok cycling the exhaust fan, I'll happily exchange the extra wear on the fan for some peace and quiet in the shop while I set up a job.

If I can't get the delay start to work, I can just add a button on the micro controller to turn the exhaust on manually before a job (and I can still turn it _off_ automatically).

See: https://www.youtube.com/watch?v=nyGHMwixa-4 -- The laser is unfinished, I'm just getting things working now.

In the end, I want to use OUT1 to detect job start/stop. When the job starts, both the Exhaust and the Air Assist turn on. At the end of the job, I stop the air assist, wait for the air to turn over a couple of times in the laser, then turn off the exhaust.

The OUT2 signal will be used to calculate the laser-firing hours for the tube.

/Mitch.

[MitchL]

Hi Swamidog,

Thanks for the compliment! I've been working on this for a long time, the journey is most of the fun! I hope this thing works - I believe I'll be able to cut, but I wonder if after all my testing the X axis still isn't fast enough for engraving. I had it running about 1000mm/sec on my benchtop, but that was without the head, E-chain, or other weight to slow it down.

I think I have a recipe that works, at least for my situation:


When OUTPUT1 is asserted, I pulse the footswitch (INPUT2) for 100ms. The job is "started" but the head hasn't had a chance to move yet. I wait for my fan to start, then pulse INPUT2 again.

It will get confused, I think, if I hit "start" on the keypad again while it is pausing. I'll probably have to live with that one.

Ideally, for me, the AWC608 should have a programmable delay start to ensure that the exhaust, air, and other things are stable.

Now I can get back to thinking about plumbing of the coolant - I'm getting close!

/Mitch.

[swamidog]

1000mm/s is *very* fast. i've done engraving on my system at up tp 700mm/s without problem. it's just all about finding the sweet spot between power and speed.

building these machines is fun, but holding in your hand a physical that you modeled on the computer an hour before is incredibly gratifying.

sounds like you've got the issue sorted out nicely.

Hi Swamidog,

Thanks for the compliment! I've been working on this for a long time, the journey is most of the fun! I hope this thing works - I believe I'll be able to cut, but I wonder if after all my testing the X axis still isn't fast enough for engraving. I had it running about 1000mm/sec on my benchtop, but that was without the head, E-chain, or other weight to slow it down.

I think I have a recipe that works, at least for my situation:


When OUTPUT1 is asserted, I pulse the footswitch (INPUT2) for 100ms. The job is "started" but the head hasn't had a chance to move yet. I wait for my fan to start, then pulse INPUT2 again.

It will get confused, I think, if I hit "start" on the keypad again while it is pausing. I'll probably have to live with that one.

Ideally, for me, the AWC608 should have a programmable delay start to ensure that the exhaust, air, and other things are stable.

Now I can get back to thinking about plumbing of the coolant - I'm getting close!

/Mitch.

[MitchL]

1000mm/s is *very* fast. i've done engraving on my system at up tp 700mm/s without problem. it's just all about finding the sweet spot between power and speed.

I'm looking forward to those experiments, I'm probably 2 weeks from firing the laser (Reci 80w) at my current "hobby time" rate.

building these machines is fun, but holding in your hand a physical that you modeled on the computer an hour before is incredibly gratifying.

I can definitely relate. This isn't my first machine, but it's my first laser. I've been building CNC machines since 2009 - my latest incarnation is a beast, 4x3' envelope, NEMA34 motors, monster 3"x6" gantry, 30mm linear rails, welded steel base. I think it's tougher than a ShopBot. I cut all the gussets and other flat parts of the laser on it. About 40 parts of the laser were 3D-printed on a MakerGear M2, and the entire design is modeled down to the fasteners in CAD.

So, in a sense, the laser itself is a physical thing that I've modeled in the computer and realized! .

I'm sure this forum has a build thread area somewhere, I should post some photos.

/Mitch.