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MKS SBASE V1.3 re-purposing

Posted by mrmuffin 
MKS SBASE V1.3 re-purposing
December 23, 2017 02:43AM
I recently bought an MKS SBASE V1.3 from amazon as it was a cheaper alternative to the smoothie board. I got it with the intention of making a water jet cutter and thought that I could use the laser functionality to run it. I am using Fusion 360 and the smoothieware post-processor to generate gcode and following the configuration instructions from the smoothieware site. What I need to do is activate an SSR when the laser begins a cut and deactivate when not cutting. From what I have seen the laser begins cutting with an S1 command and stops on S0. However the S function is technically not a command on its own and only exists where a G1,2,3 is. That being said the usual switch function will not activate a pin because it won't recognize S1 or S0 on its own. I tried to use the Input_pin function but I am not sure if the "laser" is even activating. When I send a G1 X S command through pronterface I expect my pwm and ttl pins to get a signal but it seems that neither changes.

Here is the laser section of the config and a piece of gcode that I am using to test.

I understand the the S is selecting the duty cycle of the PWM from 0 to 1. Is there anyway for a switch to use S0 or S1 as an input or should I try something else? I was thinking of setting the period of the PWM to 1 second and jumping the signal to a nearby pin to read to the SSR.
Re: MKS SBASE V1.3 re-purposing
December 23, 2017 12:34PM
Looking at "http://smoothieware.org/supported-g-codes" I don't see any laser commands
Usually the spindle commands are used to control a laser.

From above location:

M3 Starts the spindle. Only if spindle module is enabled. The S parameter sets the speed in rotations per minute
example M3 S5000 starts the spindle with PWM of 5000/Maximum value of PWM
M5 Stops the spindle Only if spindle module is enabled.

S0 sets the PWM at zero so this would also stop the PWM which stops the spindle (or reduces laser power to zero )

From "http://smoothieware.org/laser-cutter-guide"

laser_module_pwm_pin 2.5 This pin will control the laser. Pulse width will be modulated to vary power output ( PWM ).
Note : PWM is available only on pins 2.0 to 2.5, 1.18, 1.20, 1.21, 1.23, 1.24, 1.26, 3.25 and 3.26

laser_module_ttl_pin 1.30 This pin turns on when the laser turns on, and off when the laser turns off.

So M3 / M5 turns on/off pin 2.5 S0 / S?? sets PWM ratio (power level)
S??? sets PWM on pin 1.3
Re: MKS SBASE V1.3 re-purposing
December 24, 2017 01:19AM
From what I can tell now I don't seem to be getting a response from any of the laser commands such as G1,2,3 or fire. The ttl pin does not activate either. Is this unusual for this board or should I just buy a Smoothieboard?
Re: MKS SBASE V1.3 re-purposing
December 24, 2017 04:15AM
Maybe you only have to activate the pin(s) pullup resistor? Those PWM pins are often configurable to be open collector or have internal pullup/pulldown resistors.
Re: MKS SBASE V1.3 re-purposing
December 25, 2017 12:36AM

Since I was using Fusion 360 to generate G-code I found out that I could change the laser power in the post processor. Instead of generating G1S1 I can change it to create G1S255. From there A switch set to read PWM will be able to activate my SSR when the "laser" begins to cut.
That being said I am still not sure why the laser module wasn't working properly.

Re: MKS SBASE V1.3 re-purposing
December 27, 2017 03:25AM
I hope you don't get too much latency with the SSR. You only want to switch ON/OFF for cutting or planning to engrave or even grayscale too?
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