Hi,
you could use Arduinos to connect Mach4 to your drivers but the effort involved is huge.
Mach4 is a trajectory planner. It produces streams of numbers that describe the P(osition) and V(elocity) over
T(ime) in one millisecond slices. The motion controller takes that numerical data and converts that into pulse streams
for the drivers.
The external motion controllers I've mentioned have either microcontrollers, an FPGA or DSP chips on board or sometimes all
three. The combination is very much more powerful than an Arduino.
You could replicate what they have done but it would be thousands of hours worth of programming to write both the plugin
that lives in Mach4 to adapt it to your controller and also the software for the Arduinos themselves. Remember that the Arduinos
will be required to handle all the realtime functions like homing, probing, limits, THC, lathe threading......etc autonomously.
Making your own motion controller is a
HUGE undertaking.
Using Arduinos as a Modbus node is entirely doable. The node could control a spindle or maybe a tool changer, in fact that
is the ideal application for the Modbus protocol.
What Modbus cannot do is transmit simultaneously pulse streams from Mach to your drivers. One is that Mach does not
produce pulse streams but rather PVT data. Two is that Modbus cannot transmit data to multiple devices simultaneously,
or in less than a few micro seconds.
Im looking the Ethernet SmoothStepper (B-ESS), using that and its plugin im going to be able to control my drivers?
The reason im doing all of this is because i didnt know how to connect my Mach4 to my drivers.
There are a number of motion controllers that you might consider, other than making your own out of Arduinos,
including the Darwin Parallel port. The Darwin Parallel Port ($25 license fee applies) is a software driver that lives on your PC
within the kernel and produces pulse streams for the drivers out of a DB25 parallel port plug. Like the Mach3 parallel port
that it resembles it to must run on a 32 bit Windows OS PC of Windows 7 or earlier. Also like the Mach3 parallel port driver
it has the same limitations like competing software running on the PC causing stuttering and stalling of Mach. Additionally
the Darwin parallel port does not do certain realtime functions like THC and lathe threading. Art Fennerty, who wrote
Darwin has long since stated the Darwin will NEVER have those advanced realtime functions.
Mcah4 was always intended to be complemented by an external hardware motion controller. There are five US and European
made controllers ranging from about $125 to about $600. Galil also do a Mach4 compatible controller but expect to pay over $2000
for a three axis controller.
If you are looking at cheap Chinese made controllers there are none that work with Mach4. There is one company who claim
to have a Mach4 compatible controller, XHC, but it doesn't work.......avoid like the plague.
At the current time the Ethernet SmoothStepper ($190) is the stand-out controller for Mach4 in the 'value for money segment'
of the market. It has recently acquired all the realtime functionality including Backlash Comp, single point Lathe Threading,
realtime THC, spindle PID etc. It has matched and exceeded the Hicon Integra ($600 from Vital Systems) in realtime
functionality and leaves all its competing controllers in its own price bracket like the UC300 and 57CNC in the dust
in terms of realtime functionality.
Mach4 is very good software but to get the most from it really requires an external motion controller like I have described.
Thus Mach4, an ESS and couple of cheapo bi-directional BoBs will set you back about $450-$600.
Mach3 is $175 and you can use a number of motion controllers from Mach3's parallel port driver for free and a number
of cheap, if you tolerate Chinese rubbish, controllers from $50 upwards.
Craig
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