Build almost finished... need help with controls setup!
Hey Everyone - I'm building a pretty standard moving-gantry CNC Router and have all the mechanicals done but I'm in way over my head on the electronics and controls. I've been digging around on the internet for a while now and can find lots of similar setups but nothing quite the same as what I've got and I don't know enough about what I'm doing to be able to confidently bridge the gap.
Here's what I've got:
- Roughly 36"(X) x 40"(Y) x 6"(Z) cutting area with MDF spoil board.
- Aluminum extrusion & 1/2" aluminum plate frame
- Chinesium round-rail/linear bearing slides from ebay for all three axes.
- Chinesium ball screws from ebay with 4 NEMA 23 (2.8a 269oz./in) motors - 2 for X axis (1 under each end of the gantry); 1 for Y and 1 for Z
- Meanwell NES-350-24 24v, 350 watt, 14.6 amp power supply for the motors.
- Arduino UNO to run GRBL
- 4 stepperonline.com DM542Y stepper drivers
- SPDT hinge/roller type limit switches for both ends of each axis (will follow NC w/noise filtering schematic here)
- 500w air cooled er-11 spindle with independent power supply and speed control (this is a temporary compromise due to budget constraints... will replace with a full sized router or more powerful spindle down the road)
- e-stop button/switch
- lock-out power switch (similar to what many table saws, etc... come with - has the removeable red cap when off.
- everything will be housed in a modified PC tower with multiple 12v 120mm fans to move air in and out.
My biggest questions are:
1. What pins from the arduino should be connected to the DR+/-, PU+/-, MF+/- terminals on the stepper drivers
2. How do I synchronize my 2 X axis motors & drivers?
3. Can I wire my 3 PSU's (motors, spindle, fans) to ONE cord/plug? (I have 20amp service, so I think the loads work out, but I'm wondering if it will cause interference or grounding issues or something like that)
4. What is the preferred way to wire the e-stop? Should it kill all of the power to everything?
5. Since I'm using drivers and no shield, is there a way to set up some additional physical controls like "hold/resume", a probe, future coolant pump, etc... or am I over-shooting what an arduino can do?
Thanks in advance for any and all help you can provide... I kind of jumped headlong into this project with a "figure it out as I go" attitude and now my attitude has reached the limits of my aptitude, as they say... :drowning:
Re: Build almost finished... need help with controls setup!
For wiring, when in doubt, go to the source. GRBL Wiki has it all https://github.com/gnea/grbl/wiki/Connecting-Grbl
The wiki has all manner of info - worth spending time getting familiar with it.
I just wired estop to the halt input but a lot of people have a separate estop that cuts all power.
You really should get a screw shield for your arduino, makes all the wires a lot more secure.
You will find all those extra inputs are available on the arduino.
Re: Build almost finished... need help with controls setup!
Quote:
What pins from the arduino should be connected to the DR+/-, PU+/-, MF+/- terminals on the stepper drivers
Connect the DR+, PU+, MF+ to the arduino 5V
DR is the direction pin, PU is the step pulse pin, MF is the enable pin. On the arduino there is only one enable pin for all steppers.
Quote:
How do I synchronize my 2 X axis motors & drivers?
Just split the wiring from the arduino axis to both drivers
Quote:
Can I wire my 3 PSU's (motors, spindle, fans) to ONE cord/plug? (I have 20amp service, so I think the loads work out, but I'm wondering if it will cause interference or grounding issues or something like that)
20A will be more than enough. Just add the (PSU's input) amps of all 3 PSU together. Is should be below the 20 amp service assuming this is the service amp for the wall outlet.
Always connect all the PSU's to the same wall outlet. This will prevent ground loops. You than have a so called "star earth"
Just start by connecting one stepper and one driver. Remove the coupler for testing. Only connect the pulse pin. forget the enable and direction pin. The stepper should turn (in one direction only). After that, add the direction pin. If it is still working, add the Enable pin. Then add the other steppers. than limit switches and test them, estop and test estop. Finallly place the couplers. Last step is spindle on/off and speed.
Have fun
p.s. Keep the wiring from the arduino to the drivers far away from mains, PSU lines and cables to the stepper. If available, use shielded cables especially for the spindle. You could use STP or FTP Cat5/6 (ethernet network cable) for the cables between the arduino and the drivers.
An estop that kills all the power is the safest way to go.
