Smoothieboard question - Power not decreasing while lowering tubecurrent ?

[Dimitri Modderman]

Hello All,

I just converted my selfbuilt builtlog.net laser (cutting dimensions 1263x633mm) from LAOS to Smoothie.
All steps for controlling the movement went really quick, in a few hours i went from LAOS to Smoothieboard X4C.
Configuring pins is a breeze, endstops were easily connected and all. Love the board, love the layout and pin output possibilities.
Also i wanted to start using Laserweb3 to control my laser. It seemed userfriendly although i still haven't got the hang off it and think Visicut has some smart resizing tools which i seem to overlook in Laserweb3.

Coming to the cutting part was a whole different ballgame.
I used a level convertor to go from 3.3V smoothie to my 5V high voltage powersupply.
At first i connected the TL of the powersupply to ground and the PWM pin through the levelconvertor to the HV Powersupply.
This worked, but 2 things bothered me, upon turning on the power the laser went on full power for about a sec (initialisation of Smoothieboard ?) and then stopped.

I then looked through the forums to find that it would be better to make a second pin "enable" pin for the powersupply.
So changed my config and added the switch option. Much better, upon turning power on, no more laserbeam for a second!

Then i ran into the same problem another guy in this forum had, he had 5V on the levelshifter, but upon connecting it to the HV PS it only outputted 4,04V.
I had exactly this and as with him, my levelshifter was also using a 10K pullup. Since the impedance of the HV supply was very high, i lowered this resistor to 1K and low and behold, i had 4,807V on the PWM pin.
Now i was able to have a little more power. With LAOS i was able to crank out 30mA through my 100W tubed (rated at 34mA max, so well within specs) but now i only get up to 28mA but OK. I made progression.

Then i played with M3 G1 moves to see if it worked and the laser turned on nicely when using G1 commands/

So then i made a testfile that looked something like this:

G1 X10 S1 F300
G1 X20 S0.95 F300
G1 X30 S0.90 F300
G1 X40 S0.85 F300 etc

all the way down to S0.05

Put a piece of MDF under the beam and away it went!

Funny thing is that it seemed to work until like 70procent (S0.7) gradually increasing.
My mA meter which is in series with the tube reflected this. The power went down and down until it was zero.
But the cut in the wood funny enough showed something different as in the picture above.
So it seemed to go down, the amp meter went down, but the line seemed to be more power.

I am totally lost here.

I have made a video of the mA meter while cutting that line, which clearly shows the power through the tube decreasing all way to zero.
You you can find the movie here, plus the original photo:

https://hobbybob.stackstorage.com/index.php/s/LxZSPtd9q1wQ5Hw

Furthermore i had the following issues:
1. i saw that all letters where not as straight as they were with LAOS controller, all letters seem to bow a bit on the sides, not straight cuts, also the corners seem more ugly (over- and undershoot).
2. when engraving the engraving starts, then stops for about a cm of space (no output whatsoever and then happily continued and finished the whole engraving job).
3. When homing and then starting a job sometimes the X jumps to 1750mm instead of the 1400 i put in, doing a G28 followed by a G92 X1400 Y710 seems to solve this
4. Stopping a job (abort job) in Laserweb seems to hold everything. killing the laserweb3 process, then restarting the window and reconnect and then home makes it work again.

But i like to work out one issue at a time, and the power issue is disturbing since i can't find an explanation for it. Why does it go down to 70 procent (you can see the line decreasing in width and depth and then suddenly jump up...stay all the way full power towards the right until the cutoff point of the tube (which i figured was about 18-19% power, lower than that doesn't result in a cut anymore (the last cm wasn't cut at all).
So 2 issues i solved myself by researching the forum (very useful and interesting and much thanks to those posting solutions to issues!), but the issue above i can't seem to solve.

Hope someone can help me ?

Kind regards from a new Smoothieboard user.
Dimitri Modderman

[Arthur Wolf]

Try this :

1. Remove the switch module

2. Setup your laser module as such :

## Laser module configuration
laser_module_enable                          true             # Whether to activate the laser module at all. All configuration is
                                                              # ignored if false.
laser_module_pwm_pin                             1.23o!           # this pin will be PWMed to control the laser. Only P2.0 - P2.5, P1.18, P1.20, P1.21, P1.23, P1.24, P1.26, P3.25, P3.26
                                                              # can be used since laser requires hardware PWM
laser_module_ttl_pin                          1.22        #
#laser_module_maximum_power                   1.0             # this is the maximum duty cycle that will be applied to the laser
laser_module_minimum_power                   0.3             # This is a value just below the minimum duty cycle that keeps the laser
                                                              # active without actually burning.
#laser_module_default_power                   0.8             # This is the default laser power that will be used for cuts if a power has not been specified.  The value is a scale between
                                                              # the maximum and minimum power levels specified above
laser_module_pwm_period                      20              # this sets the pwm frequency as the period in microseconds

3. Put aside your level shifter, you really shouldn't need it, and it's going to introduce all kinds of trouble

4. Connect everything like this :

* PSU 5V to nothing
* PSU L to nothing
* PSU H to Smoothie 1.22
* PSU IN to Smoothie 5V
* PSU GND to Smoothie 1.23
* PSU P ( protect ) to whatever protection you have ( door, water protect etc ) then to PSU GND

And there you go, perfect control, no need for a level shifter.

Tell us how this goes.

Cheers.

[Dimitri Modderman]

Thanks Arthur for your answer. I only now saw it. I will try it either this saturday or coming monday!
I am very curious if the solution you propose works!
I will post right away after testing.

Kind regards,
Dimitri

[Dimitri Modderman]

Dear Arthur,

I tried your suggestion today.
Now stuff gets weird , really weird.

I removed the Switch module
I have setup my laser module as you suggested, both
Laser_module_pwm_pin and Laser_module_pin Since you use both options in the sample config, i tried both with same result.
Also defined a ttl pin, first i used P2.3 for PWM and 0.22 as ttl pin.

It then only gave 30mA (full power to the tube) now the funny part: the tube light up as it normally does, but no output ?
Piece of paper in front of it won't even burn.

Then i soldered on a header and used exactly your config using pin 1.22 and 1.23
I had the same result.
When i remove the 5V from the smoothie board (i use the 5V of the Zmax endstop connection) i have no output of the tube (it's fuzzy then and meter shows 2-3mA)

When i give for instance in pronterface the command G1 X100 S1 i expected it to move 100mm with power on full.
It moves, tube lights, but no output is coming from the tube, however the meter indicates 30mA flowing through the tube.
Normally i would have made a dance of cheer when the tube lights, now i am totally confused, how can my tube light up fully , meter indicating almost 30mA through tube and no output ?

I am at a total loss here!

Any suggestions would be appreciated.

Kind regards,
Dimitri



On Monday, August 29, 2016 at 2:23:48 PM UTC+2, Arthur Wolf wrote:

[Arthur Wolf]

Hello.

The correct config options are laser_module_pwm_pin and laser_module_ttl_pin, please do not use Laser_module_pin it is outdated ( see http://smoothieware.org/laser-cutter-guide#toc16 )

If your power supply is giving power to your tube, but it is not providing any light, I would expect either your tube is not connected properly to the PSU, or the tube is dead ( they are very fragile )

Cheers.

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[Dimitri Modderman]

Dear Arthur,

After a long pause, busy with other stuff, i have replaced the tube (100W tube, was broken/old).

It's taking me 4 years to complete the cutter, the tube was already suffering from age and thermal issues, because i only cooled the water with fans (computer overclock radiator with 3 12cm fans).

I have now built in the smoothieboard, a new Chiller instead of a cooler, a new tube.

Connected everything as you said and it is working!

Only issue i have now that the powersupply makes a loud hissing noise when cutting.

It's not Sparks jumping it's like the frequency or something.

Tried changing the PWM period from 20 (50Khz) to 40 (25Khz) no change in sound.

When i had it connected using 1 leg of the big mosfets to PWM it i didn't have this, but then i wasn't able to adjust the power.

Not sure how to fix this last issue, or that it can hurt the powersupply ?
A bit reluctant of using the cutter now it's so hissy.

On Wednesday, August 24, 2016 at 4:40:45 PM UTC+2, Dimitri Modderman wrote:

[Arthur Wolf]

Exactly how are you connecting the smoothieboard and the PSU ?

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[Dimitri Modderman]

Exactly as you told me, 1.23o! to GND on laserpowersupply for PWM

1.22 as ttl pin to TH on the laserpowersupply

5V from the Zmin endstop (4.78V) to the IN on the laserpowersupply

Only then i found out when i gave the command check size the laser fired a bit, so then i created a switch so the command M3 turns on the laser and M5 turns it off.

In both cases (with switch, without switch)  it works (which it didn't before or not as good, power was not easy to regulate) but makes the hissing sound.

Before i had it connected like this:

5V from laserpowersupply over a 10K resistor to IN

Then also a cable from IN to one of the legs of the small fet (2.6)

Then also from 5V to the TL pin, with also a cable to one leg of the small FET (2.4) (configured as TTL pin)

Then WP to GND and a wire from GND to Smoothie GND.

Then it worked, but the FETS were sluggish to respond (maybe because of the 10K in parallel in the lines)

So i could adjust the power a bit, but not well. Ofcourse i know i use the FETs in a way they are not supposed too.,

Following your advice worked much better, i only think the hissing is not good.

I had a small transistor circuit cooked up, to replace the solution with the FET.

I might try that, since i believe that worked as well. But your solution is more elegant.

Any advice is welcome.

Kind regards,

Dimitri

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[Arthur Wolf]

and what does your laser section in your config look like ? are you using latest edge ?

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[Dimitri Modderman]

Hi Arthur,

I can post you that tonight, i am now at work and don't have the laptop with the config at hand.

I downloaded a version of smoothie just 2 or 3 weeks ago, also changed the ttl pin name to the new style.

As said i can post the config tonight, has stuff changed last month regarding laser setup ?

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[Dimitri Modderman]

Hi Arthur,

I downloaded the CNC version from the website on 15th of August.

This is the laserpart of my config file:

## Laser module configuration
laser_module_enable                          true             # Whether to activate the laser module at all. All configuration is
                                                              # ignored if false.
laser_module_pwm_pin                         1.23o!             # this pin will be PWMed to control thelaser.

                                                              # Only P2.0 - P2.5, P1.18, P1.20, P1.21, P1.23,
                                                              # P1.24, P1.26, P3.25, P3.26

                                                              # can be used since laser requires hardware PWM

laser_module_maximum_power                   0.8              # this is the maximum duty cycle that will be applied to the laser
laser_module_minimum_power                   0.0              # This is a value just below the minimum duty cycle that keeps the laser

                                                              # active without actually burning.

laser_module_default_power                   0.3              # This is the default laser power that will be used for cuts if a power has not been specified.  The value is a scale between

                                                              # the maximum and minimum power levels specified above

laser_module_pwm_period                      40               # this sets the pwm frequency as the period in microseconds

Laser fire configuration

switch.laserfire.enable                      true             #
switch.laserfire.output_pin                  1.22                # connect to laser PSU fire (!^ if to active low, !v if to active high)
switch.laserfire.output_type                 digital          #
switch.laserfire.input_on_command            M3               # fire laser
switch.laserfire.input_off_command           M5               # laser off

First i had it configged with:

laser_module_ttl_pin                         1.22    

And no Switch section, but then it fired when i did CHECK SIZE in Laserweb,

With the switch section it's ok and can change the power nicely, but the supply hisses.

 

Does this information help you a bit what could be wrong ?

 

Thanks in advance, smoothieboard is awesome.

Have some rastering issues using laserweb4 but slowly i'll get there.

 

 Kind regards,

Dimitri

[Dimitri Modderman]

Oh and btw what does active high mean ?

I have now configured pin 1.22 just as normal (TTL ?) pin.

Does it make a difference make this an Active high pin ?

[Dimitri Modderman]

I hope you can still help me with the settings Arthur ?

I have posted above my config and wiring details.

kind regards,

Dimitri

On Wednesday, September 13, 2017 at 12:39:59 PM UTC+2, Arthur Wolf wrote:

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