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phil-barrett / grblHAL-teensy-4.x

GRBL Header for a Teensy 4
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Pre-sales questions #3

Open frdfsnlght opened 3 years ago

frdfsnlght commented 3 years ago

I'm getting ready to start a couple of projects (MPCNC and a mini-lathe CNC conversion). I have some questions:

  1. The Tindie store just ran out of the boards. When do you expect the next batch to be available?
  2. I've been reading about some of the work on grblHAL about lathe spindle sync but I'm not clear on where it currently stands. It sounds like this board will support sync through the ST0-3 inputs (index and encoder). I'm wondering if that's still the plan or do you foresee a hardware change in the future?
  3. Will this board support a MPCNC auto-squaring with dual end stops? Assuming dual NC limit switches on both X and Y, can I just wire each pair in series and connect to the X and Y limit inputs? And the steppers would be connected to X/A for the X axis, and Y/B for the Y axis?
  4. Does the e-stop switch connect to the Halt input? And a momentary, NO switch to the Fd//Hld input? What's the practical difference between these signals? Once halted, can the program be resumed by a momentary NO switch on the Cyc/St input in either case?
  5. What's the purpose of the Probe input? Is that a switch input to trigger a probe cycle, or is that the probe input itself? If it's not the probe input itself, where does the probe input connect? On a "typical" MPCNC, probe input connected to the Z-min limit, but the limit inputs on this board don't distinguish between min and max.
  6. I'm planning on someday adding a MPG, probably building it myself from buttons, an encoder, and microcontroller (perhaps a Teensy 2.x). There was some discussion of being able to connect something like that via USB to the Teensy 4.1's USB host port. Would you anticipate any problems doing that with this board? I assume there wouldn't need to be any hardware changes to the board?

Thanks for any help that can be provided. I apologize if this isn't the correct place to post questions like these.

phil-barrett commented 3 years ago

@frdfsnlght Thanks. That did it. Will update the design. Sending off the "final proof" of the Pro board for manufacturing after that. Got all my last little touches - 3.3-5 UART option (w/level shifting) and RS485 signal pin. Tested isolated PWM & 0-10V up to 100K fPWM just fine and linearity looks good on 0-10V even at 100K.

Just got back from dropping your package in the mail. Now it's in the hands of the Postal Gods.

phil-barrett commented 3 years ago

I'm using clones of Phoenix pluggable terminals (1840382 and 1897115 are the right angle model numbers). The only difference between the footprints for these and the vertical models is the vertical needs about 2mm more space towards the inside of the board. The pin spacings are identical.

Based on the datasheets for the ones I'm using (links in previous post), the total difference is 2.3mm and the distance between the two alternate pin locations is 1.85mm. In my horizontal mount layout, the connectors overhang the board by 2mm so it will fit pretty well (what's 0.3mm between friends?). The V and H receptacles will pretty much occupy the same board space.

The only concern I have is for when I have a full assembly run. Very careful instructions will be needed to prevent assembly errors.