Hello guys!
First of all, let me say several words about my experience with Mach3. A friend of mine owns a machine running Mach3 and it is the place I have the possibility to get used to Mach and get familiar with the various capabilities the system has. This encouraged me and my colleagues to build our own machine and decided to base it on Mach.
Now that the construction is almost ready, we need to consider buying the hardware in terms of a PC and the external device(be it a breakout card or a motion controller). We are not sure yet what is best for our case, I've read several discussions and have gathered some data.
Here is what is known about our machine:
- 6 axis breakout --> (we will start with 3 axes but plan to have another rotary two in the future). PUL+/PUL- DIR+/DIR- is what our drivers have.
- 0-10V, 0-5V spindle control. --> My friend's machine is using ModBus to control spindle speed. This results in delays of up to 4-5 seconds for the spindle to change its speed. That's not real.
- Several relay outputs --> Flood, Mist and Servo enable are what I have in mind.
- As many inputs as possible --> 2 limit switches and 1 home position for X, Y, Z is just the theory. With parallel ports we have 10 inputs so some extension or another general approach is needed. Another solution I considered is using the limit switches as home positions, that is supported by Mach3 as far as I read. My friend's machine all limit switches are wired to the same pin. That doesn't sound good to me, he overrides the limit switches from the special button on the Mach3 to get away from a dangerous situation.
- Real feed back if the servo motors are moving - we were away with my friend for a moment and after we got back, the machine was cutting the part on a place it shouldn't. As we checked, the servo driver for Y had a failure and Mach3 was sending pulses to no one. I imagine the three servo drivers's ALARM outputs to be connected electronically in an OR way so that Mach3 stops if any driver fails(I mean we get a single input pin occupation for all three). I've read somewhere Mach3 can stop the execution on external signal. It is safe enough for us. We can resume the program execution manually after we get rid of the servo failure.
After my research, I"ve found several breakout board items on Ebay from the seller "cnc4youstore". I won't post a direct link as it may be considered as an ad. I saw several threads from them in this forum too. They vary in price $100-$500. The latter are with a smooth stepper and Ethernet-controlled if I am not wrong. On the other hand, for a first machine, I am not feeling sure enough to go for the most expensive, most powerful, most colorful solution if you get what I mean.
Getting feedback for a particular product would give me more self-confidence to carry on and get the best ratio price/quality/reliability/needs coverage/
To summarize, we would like to build a simple in design but a reliable machine covering our needs and not much more than that.