Asynchronous control of a dual head machine?

[microjet2]

Hi,

If I have a 5 axis machine with shared X axis and dual Y and Z axis (second y and z are actually A and B), is it possible in gcode to run all axis normally (synchronously) then effectively have the g code branch in two and each Y/Z axis pair runs independantly for a while then then joins and runs synchronously again?

If not and I need to have a 3 axis controller and a 2 axis controller and two PCs with two copies of Mach3, what is the best way to "tag team" the two instances of Mach3 so they can signal each other then to start and are finished each independent block of code? Can I have the program pause itself with a M0 (program stop) then check for input from the other controller? How is this done? Is it with a macro as Gcode doesn't seem to have any conditional IF statements? If anyone has an example of controlling program flow via external events would be much appreciated.

Thanks
David

[ger21]

Originally Posted by microjet2 Hi, If I have a 5 axis machine with shared X axis and dual Y and Z axis (second y and z are actually A and B), is it possible in gcode to run all axis normally (synchronously) then effectively have the g code branch in two and each Y/Z axis pair runs independantly for a while then then joins and runs synchronously again?

I don't know how you'd write the code, but yes, it should work. The code will just have all the axis info in it. Something like:

G1 Xx.xx Yx.xx Zx.xx Ax.xx Bx.xx


I don't think your second option will work at all.

[fastnovacrash]

I am not sure if it is possible or not, but the simplest way would be to right the programme for each head separately in there own sub routines. Then, if you can, call the two sub routines at the same time on one line, your machine may just run out of memory, or just get really confused, but this would allow you to do exactly what you are looking for.

Otherwise it’s a lot off very complicated programming, and each head would have to be doing the same thing at the same time, G01, G91 and all that. That could end up rather confusing!

[microjet2]

Thanks for the suggestion FastNovaCrash. Tried it and it comes back "Two M codes of the same modal group cannot share a line". This is as expected so no surprises really. Also tried calling a macro that calls 2 other macros (against Mach 3 recommendation) and the timing gets all screwed up. It seems to switch bewteen executing one then the other but not both at the same time.

The tag team approach with 2 Mach 3 controllers will work by cross connecting an input and output signal on each and using macros to set and monitor the lines and pause and execute GCode as appropiate. One controller will need to be the master and the other the slave. Was looking for a single controller solution but looks like multi-threading is a bit behond poor old GCode.

[fastnovacrash]

I figured that would happen, not sure why I suggested it really as I was pretty sure it wouldn’t work, but hay, no harm in trying.

Not really sure about cross connecting two controllers. I’m quite new to the whole DIY CNC thing. All I can help with is the programming part of things; need any help with that then ask away. There not much about Gcode I cant help with, especially 3D machining. Oh, but don’t ask about macros, haven’t a clue there.