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« on: February 27, 2007, 12:25:20 PM »
engineeringpunk,
Sounds like a very energetic project.
S&D is short for step and direction. If you use the same amps (refering to the amplifiers - or - servo motor drivers) they are probably analogue input, not the step/direction input type.
Most cost effective would to use as much of the hardware that you have and still is functional, but that will not be the simplest way.
It will require interfacing mach3, which does step & direction outputs via the parallel port to your analogue cards (the biggest hurdle), there are some interfaces that do this but I can't help you there.
The simplest way would be to purchase servo drivers with step & direction inputs, if a Gecko is large enough to handle the power requirements of your existing servos (they are pretty good drives). Then the next hurdle is all the other IO you have for limits, tool changer, coolant etc. You will quickly run out of points on your parallel port, even if you put in an additional parallel port card. With your knowledge of PLC's you would probably want to put the less time sensitive IO on a PLC and communicate via ModBus with it. There will be a time lag between sending and receiving these ModBus points due to scan cycle time and how often Mach looks at the modbus.
Things like e-stop, limits & spindle index(1 pulse/rev index signal) you will want to keep on the parallel port for timing reasons. Tool changer, coolant, maybe spindle start, stop, direction could probably all be done on the PLC. Spindle speed, I am guessing you probably have an analogue input to the VFD, you can use a mach to output a pwm signal on the parallel port - convert that to analogue and feed it to your VFD.
Lots of info in these forums, you should have a good time with this, looks like a very worth while project where you will learn a lot.
Arnie