Newb question: Converting G-code to 1-10 VDC analog signal?

[LarryC]

Folks,

I am trying to repurpose a meter by meter XY platform into a 3d printer. The existing system uses linear motors driven by servo amps that get a 1-10 VDC control signal. I have seen a Rambo (?) controller board used on the larger delta printer that appears to control stepper amplifiers. Can it also control servo amps?

I do understand that I am building a system upside down with the XY sitting on the bottom and at high speeds the taller objects will sway like a tree. I am working with what I have.

The existing motion controller is an older two axis delta tau system that is controlled via some proprietary serial commands from a older HMI controller.

Any help is appreciated.

Thanks

Larry

[Mjolinor]

Use LinuxCNC.

[GOC]

- You might be able to modify the coding to apply an analog signal using the RAMPS 1.4 software and some Arduino hardware. If you have a nice platform I would suggest investing in some PWM Steppers and just buy a RAMPS 1.4 kit from eBay, the kits are usually under $30.

[LarryC]

GOC, the existing platform can support approximately 1000 pounds, the linear motors and amps are functional, I've got positional resolution to at least .001 inch possibly finer. It does not make sense for me to rebuild the table with steppers and linear rails.

After posting last night, it occurred to me that the serial line between the 486 HMI and the delta tau controller is probably ASCII. I am in the process of coming up with a serial tap that will let me see what commands are being set. If I am extremely lucky, that serial communications is already G-Code. If it is not G-Code but still ASCII text, I guess it will be time to find some sort "magic" to convert G-Code to whatever language the controller speaks.

[-willy-]

Why not buy a controller off the shelf for a $100 (aproximately) that will allow you to use STL files with out the hassle that you are currently enduring?

[GOC]

- Out of curiosity. If you do manage to find out how to communicate with your existing motor controllers via serial, how do you plan on keeping that in sync with your Z-Axis & Hot-End Stepper? Do you plan to code some custom controller software for this application?

[LarryC]

Why not buy a controller off the shelf for a $100 (aproximately) that will allow you to use STL files with out the hassle that you are currently enduring?

I am not familiar with the controllers you are talking about. Any suggestions?

[LarryC]

- Out of curiosity. If you do manage to find out how to communicate with your existing motor controllers via serial, how do you plan on keeping that in sync with your Z-Axis & Hot-End Stepper? Do you plan to code some custom controller software for this application?

I am ASSUMING (with all that entails) that if I find some magic to convert the G-Code to something suitable, the Z axis will still be controlled with the standard G-Code. Print a plane, index Z, print a plane, index Z, repeat. Since most of the motion is in the XY plane, the biggest delay is happening right after the Z axis move. If I perform some sort of First In First Out logic magic, the XY commands will be waiting when the Z is done moving.

I have not worked with G-Code before, so it very possible I am just blowing smoke. I will find out soon enough.

[Mjolinor]

I am ASSUMING (with all that entails) that if I find some magic to convert the G-Code to something suitable, the Z axis will still be controlled with the standard G-Code. Print a plane, index Z, print a plane, index Z, repeat. Since most of the motion is in the XY plane, the biggest delay is happening right after the Z axis move. If I perform some sort of First In First Out logic magic, the XY commands will be waiting when the Z is done moving.

I have not worked with G-Code before, so it very possible I am just blowing smoke. I will find out soon enough.

That is exactly what LinuxCNC does for you plus it controls the servos directly from the parallel port or IO on whatever embedded system you choose to use. Not a Raspi, the Raspi cannot run a real time Linux kernel sufficiently well.

[LarryC]

That is exactly what LinuxCNC does for you plus it controls the servos directly from the parallel port or IO on whatever embedded system you choose to use. Not a Raspi, the Raspi cannot run a real time Linux kernel sufficiently well.

Thank you. It looks like I have some more investigation to do.

LarryC