ShopBot System Conversion

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09 Mar 2012 21:24 #18493 by BigJohnT
I should know better than trust my memory :/

Thanks Peter

John

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09 Mar 2012 21:30 #18494 by PCW
Replied by PCW on topic Re:ShopBot System Conversion
I dont trust my memory either, I trust the (new) manual a little bit,
but I went out and looked at the red and black wires on our test plug just to make sure...

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09 Mar 2012 21:32 #18495 by crmorano
If I want to supply external power, and have a 5V supply connected to Pins 5 and 8 as well, and have W1 and W2 set to the left, would that work as well?

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09 Mar 2012 21:43 #18498 by crmorano
I would also like to thank you both for being so helpful on this topic.

The system I'm converting from has +5V available inside it rather than off the PC. Or is getting 5V from the PC a better idea?

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09 Mar 2012 21:47 #18500 by PCW
Replied by PCW on topic Re:ShopBot System Conversion
For a 7I76 PC power is fine (and simpler wiring wise)

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12 Mar 2012 15:33 #18544 by crmorano
So, I'm not sure what I am doing wrong here:
I have the 5i25 and the 7i76 connected. I have my jumpers set up to get power from the 5i25, and both CR1 and CR2 LEDs on the 7i76 turn on.
I'm trying to use PNCconf to set up the 3 axis on the 7i76. I want to be sure I'm reading this right. I've set my Mesa0 PCI Card to 5i25, and then go to the

"Mesa0 Configuration-Board: 5i25 firmware: 7i76x2" config page,
I only have the option of the 7i76x2 for the firmware, Which I think I downloaded from another thread. Is this for 2x 7i76 boards? Do I need a different one if I only have the one board?

On Configuration Page:
Watchdog Timer is set to 1007000ns, Num of Encoders: 2, Num of PWM Gen: 0, Num of Smart Serial Ports: 1, Num of CHannels: 4, Num of Step Generators: 10.
On I/O COnnector 2 Page I have:
Num 5: X Axis
Num 6: Y Axis
Num 7: Z Axis
And Greyed out after 8 and 9 (Unused) are: Num 2: 7i76 Mode 0 I/O Card off
And Step Gen's Next to each, and a Dir Gen on the line below each, all of it is greyed out.
I've changed nothing else, and there is an optiont to load the "7i76 I/O Mode 0 Card" next to SmartSerial P1-Tx, but I have not

I have an I/O Connector 3 Page:
Num 0: X Axis
Num 1: Y Axis
Num 2: Z Axis
Again similar set up with the Smart serial
I'm not worrying about the I/O ports yet, as I need to know I can drive the motors before I set up the limit switches.
I believe I can include pictures if that would make it clearer.

Now, as I continue to the Axis/Motor Config pages, I set them up to what I think is the correct setup for the motors (I'm not positive, but I'm only driving some LEDs at the moment), and connected an LED+Res to Dir0+/- and Dir1+/-. The LEDs turn on when I turn the computer/24V Supply on (And if I measure the voltage on either Step+/- or Dir+/-, its ~5V). They only turn off when I try to load the Axis Test/Tune, and then they turn back on once its loaded. Jogging any of the 3 Axis doesn't turn them back off.
Any thoughts what I'm doing wrong?

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12 Mar 2012 15:59 #18547 by PCW
Replied by PCW on topic Re:ShopBot System Conversion
IMHO I think you would be much better off hand configuring this with hal rather than trying to debug new features in pncconf at the same time as settting up a new machine.

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14 Mar 2012 14:51 #18600 by crmorano
So I have managed to actually get a motor to move around, however its calibration is horribly off (It moves way to far for each minor jog). I know the motor has a 7.2:1 gearbox built into it and this then connects from the shaft of the motor to a rack and pinion gearing for the actual travel. I do not know what the gearing is on the rack and pinion but I do have tools to measure precisely measure travel once I think I'm in the ball park.

My next question is: I have the 7.2:1 Gear ratio on the motor and 1000x microstep functionality (according to the manual this gives me 0.05degrees/pulse), how do I calculate my "step" numbers for my axis? I now have an INI file I got from Mesa which got the machine working fairly quickly by loading it into EMC directly, so it looks like all of the adjustments are in that file. What do I need to be careful about while doing these calibrations so I don't damage the system? Which is safer, setting the "step" number higher or lower than what it should? And does the drive pulse width affect the distance traveled, or is that just the speed that it adjusts the stepper and the faster you can send pulses, the faster you can move, and if I set the pulse widths to longer, then it will move slower, but also generally be safer to work with?

Also, does the "reload" functionality in AXIS under "File" reload the .INI file?

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14 Mar 2012 17:56 #18602 by PCW
Replied by PCW on topic Re:ShopBot System Conversion
First I would read the step setup area in the LinuxCNC integrators manual
If you are modifying the .ini file I sent, the SCALE parameters in each axis are
what must be changed to get the proper "SCALE" that is on inch or mm of programmed
motion results in 1 inch/mm of axis motion

The steplen/stepspace/dirsetup/dirhold parameters should be set to match your step drive requirements, but 10000,10000,20000,20000 is a good starting point if you have no drive info

Note that maximum speed and acceleration are set with the MAX_VELOCITY. MAX_ACCELERATION numbers not the steplen and stepspace setup numbers
(though they can limit the maximum velocity, the MAX_VELOCITY. setting should always be hit first when setup properly )

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14 Mar 2012 18:24 #18603 by BigJohnT
I'd stick to 10 or less micro steps, you can google and find the reason why more is not better.

The scale is how many step pulses you need to move one user unit. It's basic math to figure out the scale.

10 micro steps X number of steps per revolution for your stepper is how many steps per rev.

Say you have typical steppers that take 200 steps per rev then with 10 micro steps X 200 is 2000 steps to turn the stepper one full revolution. Next you calculate your gear reduction to find out how many revolutions of the stepper it takes to move one user unit and multiply that times the 2000 and that is your scale.

When you press the reload button in Axis it reloads the current G code file only.

John

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