Category: General LinuxCNC Questions
Here's the "buy log" and rough sketch for the overall project. Please have a look and let me know if I've missed anything....
Buying Stuff - Here's what you need:
MESA electronics: "Plug-n-go" kit with a 7177-5i25 cards. I'd get a "low profile" PCIe card and probably a DIN mount option (Should be ~$288, 7I77D-5I25 PNG KIT w/ low profile PCIe option)
Suitable touch screen monitor
Computer: The computer will have to be dedicated to the task and run Linux. It doesn't need to have a lot of horsepower. Only restriction is you need one PCIe slot so an intel NUC will not work. If you want a small one, .I'd buy something like this:ASRock J4105M Intel Celeron Quad-Core Processor J4105 (up to 2.5 GHz) Micro ATX Motherboard / CPU Combo - Newegg.com , Would need memory, a power supply and a case in addition.
You would also be perfectly well served with buying almost ANY used PC on eBay or Craigslist..
Optional: Phase converter for spindle motor: (if you want one). For a 1HP motor, this unit should work. It's $63. 0.75KW 1HP 110V Variable Frequency Drive Inverter CNC VFD VSD Single To 3 Phase | eBay. Maybe better to get a 2HP or 3HP version for margin since the cost is basically the same 2HP AC220V/1.5KW Variable Frequency Drive VFD Inverter Single Phase To 3 Phase | eBay. I have ~5 of these units now and they all work fine.
Optional: Pendant. I've valued having a wireless pendant to move the machine around for finding zero. I couldn't find the exact one I have but it's similar to this one:
WHB04B-4 XHC 4 Axis Wireless Mach3 Remote MPG Pendent CNC pendant Handwheel【USA】 651312400745 | eBay $88.
Building Stuff:
Overall: The first step once you have the parts is to mount a PC and monitor somewhere and to mount the MESA card inside the wiring cabinet. Once you have a working PC and a MESA board, we can work to get it all the other stuff connected properly and then programmed.
Computer: Once you get the monitor and PC, you will need to mount them and wire them into the system. Decide where you want the monitor and mount it in. If you put the PC in the head behind the monitor, you will need to wire the parallel cable into your wiring cabinet. If the PC is in the cabinet, you will need the monitor / power / usb from the head to the cabinet.
Mesa board: Mount the Mesa board in your wiring cabinet. I recommended you get the DIN mount version and I have plenty of DIN mount rail left over. Plus I have a bunch of DIN mount terminals that might be helpful.
Servo control: The key part is you will need to get your servo's under your control. This might be trivial, as simple as finding the +/- 10V inputs on your servo controllers but you need to get to the point where the servo motors are moving with a +/- 10V signal.
Sero feedback. I assume your motors have a quadrature encoder. You need to figure out what they output for position and how to wire that into the Mesa board.
eStop: There should be a "Normally Open" set of terminals on all of the key components that close when the component is powered on and happy. You will want to daisy chain all of these together and ultimately into the Mesa card. If one component faults, the system will halt.
Limit switches: Wire the limits into the Mesa card.
Programming Stuff:
Programming the PC: I'll handle this. Install Linux and optimize the settings for low latency. Install LinuxCNC.
Teach the system about the hardware: Make an .ini file for the Mesa cards, set up the servo loops. Map the physical inputs (limit switches, quadrature, estop, etc) to the corresponding logical inputs. Map the logical outputs (control voltage, eStop enable, etc) to the corresponding physical outputs.
Tune the servo's: Get the PID settings right for each axis. Linux CNC has some tools to make this easier.
Enable the Pendant: If you have one, this takes some programming
