Convert a Benbox engraver to GRBL

[Rick23n]

I have a chinese 16w Laser Engraver which came with Benbox to install which worked initially with NANO(324p)/LX-Nano with a CH340 chip but now the command buttons will only move the Y axis one way or activate the laser on full power.I have now installed LaserGRBL v2.8.52 which seemed to install correctly but when I import a file to print I cannot get the 'connect' button to activate. It tries to connect but then shows "disconnected" and the Session log reads: 5/09/2018 6:54:45 PM SetStatus Machine status [Connecting] 5/09/2018 6:54:45 PM OpenCom Open COM4 @ 115200 baud Ctrl-X 5/09/2018 6:54:45 PM SendImmediate Send Immediate Command [0x18] 5/09/2018 6:54:49 PM SendImmediate Send Immediate Command [0x18] 5/09/2018 6:54:55 PM OpenCom Connection timeout! 5/09/2018 6:54:55 PM CloseCom Close COM4 [CORE] 5/09/2018 6:54:55 PM SetStatus Machine status [Disconnected] 5/09/2018 6:55:24 PM Program ------------ PROGRAM STOP ------------ Please help

[Rick23n]

fantilator - I did reply to you but it is not showing- I will repeat - Command M3 S0 does NOT turn the laser ON but when I remove the yellow TTL cable, the laser comes ON full power. I have found that I CAN adjust the power but with strange settings S .0125 +++. I am not sure about grounding the pin beside the TTL yet but may do if all else fails. Yes I am using M4 with the laser mode now.

[arkypita]

• In my opinion grounding of TTL connector is not needed because the TTL ground is shared with power ground.

• If detaching TTL result in "ON FULL power" seem that your driver has an inverted logic (remember what I say some post ago about TTL control: 5V should be LaserON, 0V should be LaserOFF)

Did you have a multimeter? Can you measure voltage between GND and TTL pin and check that it vary with the S value?

• M3 S12000 (should be 5V)
• M3 S6000 (should be about 2.5V)
• M3 S0 (should be 0V)

If you don't have a multimeter, could you put a LED with 220ohm resistor series, between TTL and ground and see what append to its intensity? S12000 should be bright, S6000 half bright etc.

[arkypita]

More: As I previously say "The TTL pin is on pin D11" This is the GRBL standard. I don't know nothing about benbox but maybe the pin is not the same. If grbl control the pin D11 but the TTL cable is connected on another pin the problem would be explained.

It is not possible to see it by the picture, you should check it using multimeter.

Disconnect your pwm connector from the driver side, put multimeter in "beep" continuity function, insert one tip inside pwm connector and with the other tip test each arduino soldering.

Only D11 should "beep" when probed

[Rick23n]

Arkypita thank you for your interest. Yes only D11 shows continuity on TTL. At first at M3 S12000 when I measured the voltage there was no change at S6000. Then I started at S1 and these are the figures it showed on TTL ; S1 = 38.2mv S2 = 56.6mv S5 = 111.7mv S10 = .203v S50 = .936v S75 = 1.395v S100 = 1.85v S200 = 3.69v S255 =4.7v S1000 = 4.7v S12000 = 4.7v When I engraved an image and set Sxxxx ; Protocol Settings Buffered / Fast , Raster Unidirectional Engraving (the first voltage is on the "away" pass the second is on the "return" pass. S2 = 2.03/2.36v S10 = 2.03/2.8v S100 = 2.03/3.09v S255 = 2.03/3.13v If I set single burn (uncheck Unidirectional and restart GRBL ) then the voltage shows 2.03v on the first pass and 3.13v on the second pass. I hope I have explained this clearly.

[arkypita]

Arkypita thank you for your interest. Yes only D11 shows continuity on TTL.

This is good. Means that your Benbox board has the same pinout schematic of grbl!

At first at M3 S12000 when I measured the voltage there was no change at S6000. Then I started at S1 and these are the figures it showed on TTL ; S1 = 38.2mv S2 = 56.6mv S5 = 111.7mv S10 = .203v S50 = .936v S75 = 1.395v S100 = 1.85v S200 = 3.69v S255 =4.7v

For what you say, look like that you modulate power in a range of S0-S255, not S0-S12000 as you say some post ago.

Do you have changed those values to 0-255, correct?

[Rick23n]

Yes, in all cases I set the power to Sxxx in "Target Image" and also in grbl Config $30 with Laser Mode enabled changing from S0 up to S255. When I used setting above S255 it did not change from 2.03/3.13 Volts. on the TTL line. When I posted before using 0-12000 I was not sure of what I was doing and it seemed that I got a better burn at 12000 but now i am not so sure because 255 IS at full power (4.7v)

[Rick23n]

I should have said full power when burning at S255 seems to be 3.13v

[Rick23n]

Thank you to the above for your support. I think I have it all sorted out now except for the image size that is shown in Laser grbl in mm actually prints 3x the size but I can work with that unless there is an obvious setting that I can adjust.

[StuartB4]

Don't know why it would burn bigger than it's supposed to. Can you check your stepper motor movements are set correctly.

Easy way to do it is to open LaserGRBL and Connect. Left Click the Right slider once then use the Up-Down keys on your keyboard to set it to 20 shown in the picture below.

Move the laser to about the middle of the X Axis rail. Make a mark on the rail as close as possible to the laser on the left side of where the laser stopped. Click LaserGRBL Right arrow key once to move the laser 20mm's. When it stops measure the distance it moved with a ruler from the mark on the rail to the left side of the laser. If the measurement is 20mm's then the stepper is set correctly.

If it's different to 20mm's you have to change the $100 and $101 settings. Do the same for the Y Axis.

[Rick23n]

Thank you Stuart I will try that when this big electrical storm has passed. Maybe tomorrow

Sent from RICKs iPhone

On 26 Sep 2018, at 22:06, StuartB4 notifications@github.com wrote:

Don't know why it would burn bigger than it's supposed to. Can you check your stepper motor movements are set correctly.

Easy way to do it is to open LaserGRBL and Connect. Left Click the Right slider once then use the Up-Down keys on your keyboard to set it to 20 shown in the picture below.

Move the laser to about the middle of the X Axis rail. Make a mark on the rail as close as possible to the laser on the left side of where the laser stopped. Click LaserGRBL Right arrow key once to move the laser 20mm's. When it stops measure the distance it moved with a ruler from the mark on the rail to the left side of the laser. If the measurement is 20mm's then the stepper is set correctly.

If it's different to 20mm's you have to change the $100 and $101 settings. Do the same for the Y Axis.

— You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub, or mute the thread.

[StuartB4]

Ok Rick.

[Rick23n]

Settings $100 = 77 & $101 = 80.5 now is perfect thank you

[arkypita]

Very happy of your resut. Thanks to @StuartB4 for big effort giving support.

Will be nice if you want to draw a step-by-step guide to help other people converting a Benbox machine to a GRBL one. I think benbox is very limited when grbl has a lot more of support, UI programs etc A lot of user could be find this helpfull

[Rick23n]

I will try to explain to the best of my ability, but it may take some time to get it right. How should it be posted? On the forum? or is there somewhere else? I dont think Utube would be something that I could do.

[StuartB4]

Hi Rick. If you do decide to do a Tutorial / Guide, you might find a bit more info here that may help. Benbox Forum

[Rick23n]

Thank you Stuart. I'm not sure if I will be able to yet, I am still learning. When I have it all sorted out I will certainly give more thought to sharing my experiences with everyone. I must admit the 16000mw laser is not living up to expectations. I would have thought cutting 3mm thick MDF (composite) board would have been an easy asignment but after full power at 50mm/min and 8 passes it leaves me puzzled

[StuartB4]

Hi Rick. I noticed from the picture you posted of the laser control board with the arduino nano on it that it has the Z Axis plug in. Does your Z axis move up and down.

If it does then you could drop the laser down by a very small amount after a doing a certain amount of passes. That will set the lasers point of focus further down inside the first pass or passes.

[Rick23n]

I understand what you are saying Stuart and there is a Z axis plug-in but I don't have a Z axis so I have to do it manually until or if I build one.

[StuartB4]

Oh ok Rick.

[Rick23n]

I have added a shroud to my laser so that I can put away the glasses. It now means that I don't have to lock the door to stop anyone coming into the room while the laser is on. I saw on another forum someone wanted to get rid of the glasses so maybe this will help them. I did NOT use the 450nm rated material ($300/sq ft) but I am assured that the 3mm dark green acrylic is safe. I have also added a red laser point to allow positioning of the laser when I need to have margin insets. The addition of an LED allows vision through the acrylic to show the workspace clearly. I have also ordered a Z axis to be added to my laser. I am not sure yet how I am going to control it as grbl has the z axis in the config but the main control panel does not have z axis controls !(or have I missed something ?) Also controling the number of passes is not capable in grbl. It would be nice to do this automatically for cutting.

[StuartB4]

Hi Rick. I think you can use 2 Custom buttons for the Z Axis up and down. I don't have a Z Axis but made 2 buttons for when I get one. They seem to work when I change the Z in the GCode to X or Y so I assume they will work for Z. I set the movement to 0.10 mm and when I press either button the axis moves a tiny amount. Obviously changing that number will move it more / less depending on the setting. I set Up as -0.10 and Down as 0.10 Like this: G91 Z-0.10 and G91 Z0.10

You will probably have to change this setting to match the stepper motors Steps Per Millimeter on the Z Axis.

[Rick23n]

Thank you for that Stuart, I am still learning but it makes sense. What were your thoughts on the multiple passes for cutting?

[StuartB4]

Hi Rick. May be it's me but I don't quite understand what you mean by automatically for cutting. I assume you know about the number of passes adjuster, at the right of the Progress bar.

[Rick23n]

I need new glasses!! my apologies I was thinking I had to do the extra passes manually by re-activating the G code

[StuartB4]

Thats ok Rick. Like you said, still learning. I like to think we never stop.

[Rick23n]

Everything has been working great, then I decided to add a 'Z' axis. To do this I needed to upgrade my controller to accommodate the 3rd axis. I bought the controller (see picture) and the 'Z'axis from Banggood and set it up using the original 2 axis controller to test and after a few adjustments, that worked fine ( I used the X axis driver to test the new stepper). Now with the new controller I cannot turn the laser off or move the laser in any direction. I have used the jumpers supplied under the stepper motor drivers but am not sure if there needs to be any other bridges

Stuart, you said you intended to add a Z axis at some time. Have you done this yet? It has cut down my print area substantially but I don't need it large at the moment. I can always add rails later.

[StuartB4]

Hi Rick. No I have'nt added Z yet.

Are you sure you have the driver boards the correct way round. This picture shows the current adjuster pot facing away from the motor leads, your's looks like it's facing towards them

[StuartB4]

Wow this is confusing. This image is from an item on Aliexpress. It shows 2 pics of the same board but the driver boards are different on both pics.

[StuartB4]

Do you have a multimeter to check the arduino pins connections to the laser. With everything switched off you could check the Arduino pin that should go to the laser PWM wire (Yellow).

[StuartB4]

Rick. Are you sure the laser connects to the 3 pins you have yours on. In the image above they have a jumper on 2 of the 3 pins where you have the laser plugged.

[Rick23n]

Slight problem-this board does not seem to have a TTL connection

[Rick23n]

Yes I see the jumper now and did realize that was why the laser could not be turned off - it is 12v power out but not controllable for the laser. I will try to connect to the laser Interface but that does not appear to have any voltage

[Rick23n]

With the jumper on the 12v I now have power to the stepper motors but will have to configure the Z axis motor the same as the others as the command you gave me does not work but when I had the Z axis connected to the X stepper it worked great on the old board. I still cant see the PWM pin for the TTL

[Rick23n]

Now with this $ command $J=G91Z20F500 the Z axis is moving correctly and the position of the stepper drivers are with adjuster pot facing the motor leads. Am still looking for the TTL connection. Cheers

[Rick23n]

Still cannot get power to the laser

[StuartB4]

I've just been looking at some more images of the board, I think you are right about it not having a PWM connection for the laser. The other way to do it is to change your setup completely. If you use an Arduino UNO and a Protoneer CNC shield, but thats more messing about and more expense. You can use your existing motor driver boards though. The shield is actually designed and sold from New Zealand, closer to you than me in the UK. The website is really helpful as well, good support. https://blog.protoneer.co.nz/arduino-cnc-shield

[Rick23n]

Thank you for that info, will re-look tomorrow 1.00am now Still can't work out how to power the laser off this board unless it requires fly leads from the 12v output to the connections shown as laser interface and high power ?

[StuartB4]

Ok Rick. You could probaly connect the + and - of the laser to the 2 pin laser connector on the board, but you would still have to connect the yellow wire to pin 11 on the Arduino so it gets the PWM signal from it. Sleep tight. Zzzzz

[Rick23n]

Hi Stuart. The 2 pin laser connector does not activate the laser when I set up a print job. The only way I have been able to get 12vdc to those pins is to run a negative rail from the 1st (-ve) of the 3 pins where 12v comes in from the power supply(where I had to put the jumper on pins 2/3)of course when I do that I have constant power to the laser and connecting the yellow TTL cable to pin 11 on the Nano does nothing. I have asked BIQU (the manufacturer) but all they said was "they don't have the files for it and besides the technician isn't here" (great!) I would like to get this controller up and running but may have to invest in the one from Protoneer as you suggested or find another like this one that supports a laser up to 18W

[StuartB4]

Thats strange Rick, 18 Watt ? the picture shows a TTL Laser Driver Board that can only handle 3 Watt Lasers. I use that board myself for a 2 Watt Blue Laser. I know it looks really messy but it works.

https://www.youtube.com/watch?v=5hvh9pSgPL0&feature=youtu.be

[Rick23n]

Hi Stuart, these are the specs for the controller I posted https://www.ebay.com.au/itm/GRBL-Laser-controller-board-CNC-USB-3-Axis-Stepper-Motor-Driver-Controller-Board-/292652076251 GRBL Laser controller board CNC USB 3 Axis Stepper Motor Driver Controller Board for CNC Mini engraving machine This is a GRBL open source code-based laser, can be used for Laser Engraving machine, CNC Engraving Machine etc. product specifics: 1.Application：use for DIY mini Engraving machine or Toy laser engraving machine 2.Applicable software：GRBL control、Un Gcode Sender、 GRBL controller，or other software that supports GRBL code 3.Communication:USB（USB-CH340）. 4.Power supply: voltage: 12V current about 4A , according to the load to increase or decrease the power supply. 5.Stepper motor driver: A4988 motor driver,16 microstep 1.5A phase current output 6.Support stepper motor: NEMA17 NEMA23 stepper motor, phase current less than 1.5A . 7.Laser interface: 12V or 5V, power less than 18W laser module. 8.Spindle motor interface: the maximum support 400W DC spindle motor. 9.With fan interface and TTL signal output interface (for controlling the laser module with TTL module). 10.Limit interface: 3-axis limit interface. 11.Probe interface: for Z axis tool zero. 12.Power interface: DC-005 2.0 interface I guess you have to be careful when you don't know what you are doing! Question : would it be possible to use my original board (2 axis controller which was working ok) WITH the new 3 axis controller somehow? I really don't want to do that, I would like to get the new one to work properly. The only thing not working on it is the laser will not fire up from the Arduino

[StuartB4]

Thats interesting Rick. I noticed it says it has a TTL OUT. The bottom right socket. If it has then that would come from the Arduino chip, the square one in the middle of the board with all the legs around it. The other chip above it is the Communication:USB（USB-CH340） If the TTL does come from that chip then I don't understand why it would need the extra driver board that's pictured with it. Surely if it's a TTL out then you should just be able to plug the yellow wire from your laser driver board in to it to get the signal, and plug your laser + and - in to the socket next to it. The TTL out on that board is a 2 pin connector, the second pin is probably TTL - which you would probably have to ground, it may be connected to the - pin on the laser connector next to it.

I'd like to see it wired up to a machine but have looked around and can't find any more info on it anywhere. Looks like a nice board though.

[Rick23n]

I havn't bought that controller yet but I may have to if I can't get this one up. So the Arduino is built into this board?? not like the one I have now where the Arduino Nano is a plug-in that I had to flash with the gbrl hex. Have I got that right?

[StuartB4]

Just found this, looks like it's made by or for Sainsmart. They might have more info about it as they sell it on their website here: https://www.sainsmart.com/products/3-axis-grbl-usb-driver-controller-board

Also they have a better image where you can see the TTL + and - markings on the board.

[StuartB4]

Yes Arduino built in. It's the Atmel Mega328P chip.

[Rick23n]

OK Yes that board you posted appears to be the same board I'm talking about, certainly the write-up is identical even support up to 18w laser (Which you queried) I'm just about over this 3 axis one I have now absolutely no support from BIQU or Banggood, Banggood told me to find something on Utube!

[StuartB4]

Yeah that happens with a lot of stuff, can't wait to sell it you but then no support. I've asked Sainsmart for some more info, just waiting for a reply, we shall see.

[StuartB4]

I noticed it comes with a CD as well. I suppose that will be a bit of software for sending your images to the machine, something similar to LaserGRBL, and also the USB-CH340 Driver, which usually has to be installed first so it can communicate with your computer.

[Rick23n]

I have also tried connecting the Grd pin of the Arduino to the Neg of the laser, I thought maybe it would act the same as when I connected the 12v Neg to the laser and got full power but would only activate when the laser was printing, ALAS that doesn't work either

[StuartB4]

Hi Rick. I received this today from Sainsmart. Handy but not a mention of how to use the TTL option or if it needs an external TTL board.

Hey Stuart,

Thanks for reaching out!

Sorry that our product team is on business trip at present and we cannot answer your questions directly.

Here is the manual for this item: http://wiki.sainsmart.com/index.php/101-60-508

If you need any further help from us, please let me know.

Best regards, Lynn.