New J Tech owner needs setup help


Continuing the discussion from J Tech Laser integrated with X-carve grbl (Inventables/Master version 1.0c):

I don’t know the hookup procedures for the laser (I don’t have one). I think the J Tech instructions are suggesting that you can use the variable spindle wires to get the PWM signal from the Arduino to the laser controller. I defer this question to someone that has the laser.

To use the multi-mode grbl you just have to load the .hex file into your Arduino. If you don’t know how to do that I can help with that. Be sure to read the Readme included with the release.

You would use the normal Inventables grbl settings for spindle work and a different set of grbl parameters for using the laser.

If you don’t want to “get under the hood” and you just want to get to the good stuff, you might consider getting PicSender. It’s only $24.95 for a license and it will handle many of the issues with switching between laser and spindle mode.

We could ask Jeff ( @picengravertoo ) if he would post a set of typical grbl parameters for laser work to get you started.


Thanks Larry.

Here are the setting changes I make for increasing the performance to raster laser engrave photos.

$0=30 (step pulse, usec)
$1=255 (step idle delay, msec)
$10=18 (status report mask:00010010)
$11=0.005 (junction deviation, mm)
$110=5080.000 (x max rate, mm/min)
$111=5080.000 (y max rate, mm/min)

Here are the acceleration settings for the X-Carve with nema 23 steppers as recommended by J-Tech Photonics.

$120=8000.000 (x accel, mm/sec^2)
$121=8000.000 (y accel, mm/sec^2)

Our Shapeoko 2 6W laser engraver with nema 17 steppers and Kevlar reinforced timing belts, the X&Y axis accelerations are set at max.

$120=12000.000 (x accel, mm/sec^2)
$121=12000.000 (y accel, mm/sec^2)

All other grbl settings for the Laser or Spindle Mode are the same, except the $30, $31 for the maximum & minimum PWM values & $32 for enabling/disabling the Laser Mode.

In the PicSender GRBL menu, the settings can be changed easy and saved for the different modes with two separate text files Spindle.txt & Laser.txt. Then, when switching modes, the settings will automatically change in Larry’s grbl 1.0c.



After looking at the links that Jeff provided in the other thread I think I can help you with this now.

How do you currently have your spindle control hooked up and how do you use it?

Do you have a variable speed spindle?

Do you have a DeWalt and use the spindle control signal to turn a relay on/off for your router?

Do you have the spindle control signal wired from the Arduino (pin 11) to the Inventables power control module on the power supply and then the 24 volt control output wired to a relay?

Give me as many details about this wiring that you can.

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Here is my wiring setup coming from the stock controller
I use a 24volt cooling fan for better cooling and I had one laying around it is tied in to the relay for my dewalt. unless you are using the cooling setup from jtech

this is a photo from inventables I edited as my camera is lacking battery power

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Thanks Shane

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Ok Have done the hookup as indicated here and if I try and connect automatically as in xcarve machine setup I get a quick on off flash of the laser. (connected the yellow and black wires from arduino to the laser driver) If I try and use picsend with a sample file Laser won’t come on when running unless I put driver in CW. ???

Does yous sample file have a M03 to turn on the PWM & a S command value for the laser power level?

In PicSender Laser mode, select the M03 button and jog the S up at steps of 5. Does it come on and increase in brightness each incremental jog?

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The Roy Rogers file does have M03 I set the power level to 12000 full power just to see if it would work selected M03 and it flashes instantaneously then nothing.

I think I have found the problem…and I feel like a fool! My ground wire connection came loose…I am in the process of resoldering.

ok…so it will turn the laser on and off automatically now But the file won’t turn the laser on after it is sent

What program are you using to send your G-code to the laser?

You may have a setup problem.