Operate a Pneumatic air cylinder for Z-Axis movement

philmurp
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by philmurp » Fri Nov 22, 2013 12:32 am

cvoinescu wrote:I'm pretty sure the Sparkfun tutorial turns the Ardunio into a full programmer, so you could burn both the bootloader and the firmware (GRBL). However, if you're not careful, burning the firmware will erase the bootloader -- so it's easier to burn just the bootloader with the other Arduino, then burn the GRBL .hex the usual way, via USB.

When I am trying to burn the bootloader, it says this in the tutorial: On the Arduino Uno, you'll need to connect a 10 uF capacitor between reset and ground (after uploading the ArduinoISP sketch)

Is this between the board doing the programming reset and the board to be programmed ground?

cvoinescu
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by cvoinescu » Fri Nov 22, 2013 1:59 am

I'm pretty sure they mean the working Arduino, the one used as the programmer. I'm also pretty sure, given the SparkFun tutorial, that you can omit that capacitor. I'd say follow the SparkFun tutorial exactly, and you should be fine.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

philmurp
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by philmurp » Fri Nov 22, 2013 7:51 pm

cvoinescu wrote:I'm pretty sure they mean the working Arduino, the one used as the programmer. I'm also pretty sure, given the SparkFun tutorial, that you can omit that capacitor. I'd say follow the SparkFun tutorial exactly, and you should be fine.

Upgrade Successful to .8c. Used the sparkfun tutorial, thanks for the help. I have been getting some weird results from my board however. Occasionally when I plug the board into my serial port it doesnt recognize it. Then if I reattempt to plug in the usb cable again it will fry my USB and several other drivers, causing me to system restore. Any idea on why this could be happening? BTW, this happened before the .8c upgrade as well.

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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by cvoinescu » Fri Nov 22, 2013 8:54 pm

Glad the upgrade worked. Now you can have proper homing/limits and access to one more bit to control (coolant).

No idea what could be causing that. I've plugged and unplugged many Arduinos over the last few months and the system is still fine (I think my current port is COM28 or so).
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

philmurp
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by philmurp » Sun Nov 24, 2013 10:32 pm

When using the homing cycle, I only want to home my X and Y axis. So I have installed my limit switches and set $16=1, then I set $17=1, then to do the homing cycle I do:
G28.2 X0 Y0
Is that homing setting correct so that it will not attempt to home my Z axis?

Also, do you know of a way I can control a small LCD screen through this motor shield/seeeduino board? I would ideally like to output what orders I am picking as they are picked onto a screen.

Thanks,
Phil

philmurp
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by philmurp » Tue Nov 26, 2013 2:18 am

cvoinescu wrote:GRBL 0.8c has direct support for limit switches on all three axes, and a separate emergency stop input. You don't need to wire them together, and they're more useful wired separately (because the limit switches can then be used for homing too).

GRBL expects the pin to be pulled low when the limit is reached or the e-stop is pressed, and supplies weak pull-up resistors for that. For the limit switches, there are two strategies:
1. Normally open (NO) switches: wire the two limit switches on each axis in parallel, between GND and the respective input pin (D9 for X, D10 for Y, D11 for Z). Add an optional pull-up resistor (around 1 Kohm) to VCC for each pin.
2. Normally closed (NC) switches: wire the two limit switches on each axis in series, between VCC and the respective input pin. Add a pull-down resistor (required, around 1 Kohm) to GND for each pin. This method has better noise immunity and practically eliminates false limit switch triggering. If you're a purist, you'll want to recompile GRBL with the internal weak pull-ups disabled, but it works just fine even with them enabled too.

Usually, emergency stop buttons have two sections, one NO and one NC. Wire the V+ motor supply through the NC section (so that pressing the switch cuts power to the motors), and wire the NO section between the e-stop input pin (A2, if I recall correctly -- do check the GRBL wiring diagram) and GND. To avoid false triggering in a noisy environment, a pull-up to VCC is a good idea (1 Kohm or so).
When using a resistor in order to eliminate noise in the NO option, can I get away with using a 10K ohm resistor ? I have a few laying around so that would be convenient.

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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by cvoinescu » Tue Nov 26, 2013 9:09 am

Better than 100 K, for sure. 10 K will be enough in most cases.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

philmurp
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by philmurp » Tue Nov 26, 2013 3:41 pm

cvoinescu wrote:Better than 100 K, for sure. 10 K will be enough in most cases.
When I wire my limit switch, and then enable hard limits, I cannot move my steppers. No matter what command I input, it will not execute. It seems like my limit switches are freezing my system. It doesnt give any alarm or any indication that the limit switch has been triggered, when I try and make a move to say G0 X-2, my X-Axis light flashes for a second then the system doesnt recognize any commands beyond that point. When I try a soft reset of GRBL it says 'wait interrupted by user'. I have tried using just one X-Axis limit switch and all sorts of combinations but I cannot figure out what is causing this issue or even what the issue is. When I close out of my grbl controller and restart the system and input $16=0 then everything works fine. Does this sound like one of my settings is wrong or maybe my wiring?

P.S. I have also created a new topic on this issue with the thinking that this may be a common issue, the link is: http://www.shapeoko.com/forum/viewtopic.php?f=10&t=2284

philmurp
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Re: Operate a Pneumatic air cylinder for Z-Axis movement

Post by philmurp » Wed Dec 04, 2013 7:35 pm

So when I try and move my air cylinder in the vertical direction, as it goes up my system randomly seems to catch and loses distance so it can find where it is. I have tried all sorts of things and cannot figure it out. Is there any reason you could see this happening? and more importantly are there any setting you may know that I could try out to try and figure the problem out?

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