Two Machines from one PC

[ngwagwa]

Regarding synchronised Xand Y movement the G01 command tells the machine to move straight to the stated x,y & z so there won't be any issues there.

The Mach 3 uses the serial port to control the VFD as this was the easiest way to do it with existing boards in the unit.

[AndyUK]

Regarding synchronised Xand Y movement the G01 command tells the machine to move straight to the stated x,y & z so there won't be any issues there.

Mach3 is responsible for converting that single gcode command into the pulses for the steppers. It's the output of those pulses which I'm suggesting might be affected, not the interpretation of the gcode.

Think about that Gcode command - the number of pulses on X, Y and Z to reach the desired location depends on where the machine currently is. G01 also implies that the movement is linearly interpolated (i.e. it has to move in a diagonal line, not two sides of the triangle.) The synchronization and output of those pulses in a timely manner on each axis is very important.

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[Neale]

...and to put some numbers on that, at 750mm/min, Mach3 will be driving that parallel port at, maybe, 2000 pulses per second. 10 msec delay while the cpu is doing something for the other job means that 20 pulses will be delayed or maybe even lost. At best that means rough running as the steppers are continually changing speed due to varying pulse rates and at worst missed steps and lost accuracy.

You originally asked for people with experience to respond. I suspect that you might have trouble finding anyone who runs like this because it's such a potentially dangerous way to go. You are even recommended to avoid things like internet browsing while running Mach3 for these reasons. Use a motion controller like a UC100 and you might be in with a chance as the device unloads a lot of the time-critical pulse generation from the PC.

[cropwell]

I am long term friends with owner of Computer Services Nottingham. If my Mach 3 PC crashed, I would get an old machine for free, that somebody has traded in and load it up with my software from the mirrored NAS box. I speak from experience. That way you get a PC good enough to run the fairly low demands of Mach3 and with a parallel port.

My systems are all networked and the Mach3 machine has the Internet Gateway disabled, so no stupid interruptions. All my Gcode is generated on my Win10 machine and filed in the NAS box, so a hard drive failure on the CNC machine has low impact.

Even my 3D Printer has a Wifi enabled SD card, so I can download to it easily.

[magicniner]

See how it goes, but a fundamental misunderstanding of how Mach3 works with the PP seems to be at the heart of the assumption that this will not be problematic.

[cropwell]

See how it goes, but a fundamental misunderstanding of how Mach3 works with the PP seems to be at the heart of the assumption that this will not be problematic.

In order to control the PP effectively Mach 3 has its own driver with high priority control of interrupts. That is why I endorse a separate machine. It simply takes control of the interrupts, which can severely affect any other software running.

[Boyan Silyavski]

Best would be 2 machine and no PC. Each machine its own controller. Why people love so much mach3 when dedicated controllers are so much better and cheap nowadays, i dont get it. Obviously the desire for suffering...