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grblShield FAQ
Most of these questions here are about whether or not grblShield will work for a given application, sizing motors and power supplies, etc. For details of actually getting and using grblShield, see these other pages:
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grbl project wiki - Information about grbl itself
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Getting grblShield - To purchase grblShield or a grblShield bundle (grblShield with an preloaded Arduino)
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Getting grbl - How to get the grbl firmware onto your Arduino
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Using grblShield - A guide to setting up and using your grblShield.
- Troubleshooting grblShield - If you're having problems please start here
- What Arduinos will grbl / grblShield work with?
- What size motors can it drive, and what do you mean by "2.5 amps per winding"?
- Can I drive 2 motors with the Y (or some other) axis?
- What voltage and how big a power supply is needed?
- Why only 8x microstepping? Isn't 16 or 32 better?
- How about cooling - do I need heatsinks and/or a fan?
- What version of grbl should I be running?
- How do I get grbl onto the Arduino?
- How do I set up grbl/grblShield for my Shapeoko?
- How do I connect endstops for grbl?
GrblShield works with any Arduino that grbl works with and that has a standard Arduino shield connector pinout. It works with both R2 and R3 Arduino footprints. Realistically speaking this means grblShield works with Unos and some of the older Diecimila's. Grbl does not run on the Due, Leonardo, or MEGAs. GrblShield does not plug into non-standard footprint Arduinos such as the lillypad or the nano.
Almost any NEMA17 motor will work, and most NEMA23's will work. The chips are rated to 2.5 amps per winding, but if you are driving them that hard (or harder) you should really fan cool them.
Yes.
The power supply must have adequate current to drive the total number of motors in your setup. Most NEMA17's take 1-2 amps, NEMA23's take 2 amps or more. The stepper drivers can source up to 2.5 amps (with cooling). A 4.5 amp supply is sufficient for NEMA17s, where 6 or more is recommended for NEMA23s - up to about 15 amps for heavier applications. At higher current levels cooling becomes the biggest issue.
Voltage can be from +12 VDC to +30 VDC. We recommend using a 24 volt supply for better motor performance. The motors are more snappy, have more torque at speed, and (ironically) run cooler than with a 12v supply. Also, many 24 volt supplies have an output adjustment potentiometer that lets you go up as high as 30v.
We love the Meanwell NES-350-24 (24 VDC @ 14.6 Amps). About $50 on eBay or Amazon. See the 6 amp little brother for somewhat less. Flip the switch on the side of the supply for 115 volt operation.
Your exact setup will vary depending on a few factors, but here are some good starting values taken from this thread on the Shapeoko forum
$0=43.740 (x, step/mm) $1=43.740 (y, step/mm) $2=640.000 (z, step/mm) $3=30 (step pulse, usec) $4=1000.000 (default feed, mm/min) $5=1000.000 (default seek, mm/min) $6=160 (step port invert mask, int:10100000) $7=25 (step idle delay, msec) $8=25.000 (acceleration, mm/sec^2) $9=0.050 (junction deviation, mm) $10=0.100 (arc, mm/segment) $11=25 (n-arc correction, int) $12=3 (n-decimals, int) $13=0 (report inches, bool) $14=1 (auto start, bool) $15=0 (invert step enable, bool) $16=0 (hard limits, bool) $17=0 (homing cycle, bool) $18=0 (homing dir invert mask, int:00000000) $19=25.000 (homing feed, mm/min) $20=250.000 (homing seek, mm/min) $21=100 (homing debounce, msec) $22=1.000 (homing pull-off, mm)
The following are all really questions for grbl, not grblShield, but in an effort to make this easier we also answer some questions here or refer you to the grbl wiki
Use the pins labeled here.