@Zax I wish my situation were as easy as in the US but I am based here in the Philippines.
An after sales agent of Banggood contacted me today for clarification. I hope this gets settled fast. I was already looking forward to use it as soon as I ordered it. Now, I just want to get it working so people stop telling me "I told you so."
More numbers don't mean more power. You are using an 8 bit processor so there are 255 steps from 0-100%. If you set your max at 255 then 1 change equals 1 step. If you use 1000 as your max then you have to change your power by 4 to see a change in laser power. So basically power 100, 101,102,103 are all the same power level and are 10% power. 104 would be 11% power. So using anything more than 255 steps is deceiving yourself into believing there is more adjustment than there really is. No matter what you use as a max power number 100% is 100%. If you set your firmware to 255 max and enter a power of 1000 you only get 100% power not 300+ percent.
Your G-code should begin with G01 (or G1) and include M03 to enable the laser.
If you want to learn another technique, take a look at G-code generated by T2Laser using Velocity Mode. It scans the line continuously and uses the feed rate to change the burn, much more efficient than changing laser power at each dot and it doesn't require PWM/TTL.
The normal method is to use the S value (spindle speed which we use for laser power) and change it for each grey scale change. T2Laser is intelligent and generates smaller G-code by only changing as needed so you will often see longer lines as you described.
I know a different XY Plotter that can be controlled through RoboPaint, which contains an API server that allows to write own software to control the plotter. It would be great if something could be done with EleksDraw which is not as expensive as other plotters. I am wondering if anyone had success to control the EleksDraw with Java or other language or where I can find more info on that.
Does the evilmadscientist robopaint work with grbl based systems?
Otherwise you need to buy the eibotboard, the control board for robopaint.