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Arduino Rotary Table for Dummies

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dazz

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Hi
So if the motor outputs are not protected from a short, that is poor design. There should at least be a fuse. A better solution would be current limiting.
You should first check that there isn't a blown fuse somewhere.

If you or someone you know has some electronics knowledge and test equipment, it should be relatively easy to fault find and fix. Just compare the working outputs with the one(s) that don't work to pinpoint the faulty component.
 

weir-smith

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Going back several posts, if you shorted out one pole of the motor, then it should survive as the driver is current limited. If you shorted adjacent poles the outcome could be problematic and to work it out would take a little time via vector anylises. I suppect that this is the case and you have exceeded the voltage ratings of the driver. Since the driver is probably dead, disconnect the motor, turn it on and measure the motor voltages which should be slightly lower than the supply voltage. Disconnecting a stepper while energized causes very high back EMF which could be hundreds of volts and will kill the driver output chips every time.

As for changing the ratio, I have modified the Sketch so that I can have three different ratios eg 90 to 1, 60 to 1 and 40 to 1 via menu selection. With my modified Sketch, you can have any ratio with in reason just by changing one number. I have made 5 of these controllers for different people who couldn't work it out for themselves.


Happy to share both Sketches with any one who wants them. p

Bruce
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SailplaneDriver

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I haven't seen any posts as to how to mount the stepper to the rotating table. I have a 6" Phase II and chose to use a clamping system on the shaft housing. Here are the drawings for what I did. An alternative is to make a solid plate instead of the mount on sheet 2 and attach it like you would index plates. I use a spiral aluminum coupling between the stepper and the rotating table. Here are the drawings if anyone wants some ideas of a mounting arrangement. You will need to adjust the dimensions to your particular rotating table and shaft coupler. It was done in Fusion360 if anyone wants the CAD files. I'll post some photos when I reattach the stepper motor after fixing the electronics.
 

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iamroyce

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I have not done much yet but plan to set up and try the code for learning purposes but looks good so far.
 

iamroyce

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Going back several posts, if you shorted out one pole of the motor, then it should survive as the driver is current limited. If you shorted adjacent poles the outcome could be problematic and to work it out would take a little time via vector anylises. I suppect that this is the case and you have exceeded the voltage ratings of the driver. Since the driver is probably dead, disconnect the motor, turn it on and measure the motor voltages which should be slightly lower than the supply voltage. Disconnecting a stepper while energized causes very high back EMF which could be hundreds of volts and will kill the driver output chips every time.

As for changing the ratio, I have modified the Sketch so that I can have three different ratios eg 90 to 1, 60 to 1 and 40 to 1 via menu selection. With my modified Sketch, you can have any ratio with in reason just by changing one number. I have made 5 of these controllers for different people who couldn't work it out for themselves.


Happy to share both Sketches with any one who wants them. p

Bruce
WESTERN AUSTRALIA
Hi Bruce, I would love to get a copy of the sketches as I are retired and am interested in learning about the Arduino and steppers. It gives me something to fill in my spare time. I did 2 years in a tool making apprenticeship and moved up country and finished my apprenticeship in fitting and turning. My email is
roycesouthen@gmail.com I have been working on using DC motors as steppers and ran an big old Cincinati mill with them for milling encoder disks.
 

SailplaneDriver

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SailPlane Driver - where did you get the electronics box?
Aliexpress. Look for post #46 in this thread.

Everything will fit but it is tight. I used industrial double stick tape to hole the boards to the bottom of the case. The display will center in the existing cutout if you modify the two top holes in the board to match the position of the screws that clamp the case together. You also have to cut off the four pins on the serial board and solder directly to the stubs since they interfere with the posts in the case. An alternative is to enlarge the cutout and shift the display down toward the keyboard.

I also wound up removing the headers and soldering directly to the Arduino for a better connection.
 

Antonio0022

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Hi everyone, I'm an electronics student and I'm looking for a project for a rotating table and I came across this one, I congratulate you on the realization that seems to be really good, now I'm also replicating the same project, I use a nema 23, and as a driver a tb6600, I hope that in case of problems you can help me, further complements for the project
 

SmithDoor

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I seen stepper motors used but best is encoders. Stepper motors and drift as you machine.

Dave

Hi everyone, I'm an electronics student and I'm looking for a project for a rotating table and I came across this one, I congratulate you on the realization that seems to be really good, now I'm also replicating the same project, I use a nema 23, and as a driver a tb6600, I hope that in case of problems you can help me, further complements for the project
 

animal12

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so Dave , your talking a stepper with a encoder attached ? I'm interested to learn more
thanks
animal
 

ignator

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so Dave , your talking a stepper with a encoder attached ? I'm interested to learn more
thanks
animal
Most stepper motor systems are open loop. The idea is the stepper has enough torque to move when commanded, and not miss a step. If a step is missed, you don't know until the part being machined is trashed. With encoders, you count the movement of the stepper shaft, to ensure what was commanded occurred. The same processor that is driving the motor, can also read the encoder. But there needs to be some trickery in the code, like making the encoder edge triggered interupts, so no counts are lost.
 

xpylonracer

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There is no reason why standard steppers can't be used, but make sure you use a suitable power output to run the table without losing steps also a good controller with an adequate power supply, 24/36/48 v output.

The disadvantage of the std stepper are detailed in an earlier post and may of course be better to use a closed loop system.
 

Antonio0022

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hi everyone, I have a problem, I can't set the ratio, in my case I have a 1: 1 ratio but when I set 1 in the settings, the engine makes the wrong angles
 

BWMSBLDR1

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Dave, let me thank you for such a clear and understandable explaination of how to set up controls for a rotary table. With these skills I expect you to have a great future in your chosen field! Bill in Boulder CO USA
 

SmithDoor

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I talk about a using encoder or a stepper motor.

A stepper motor can be used with a encoder but not need, a good DC motor will work too.
The stepper with encoder would great on a lathe or mill. The stepper can give a wide range in speed. A dividing head and rotary table can use a DC as can be slow down.
You need to program for a brake too. If do not have have a the motor will work hard to stop drift.

When looking at encoder there two types.
1) reads single direction
2) reads both directions this the one you want.

Dave

so Dave , your talking a stepper with a encoder attached ? I'm interested to learn more
thanks
animal
 

awake

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While it would be possible to use a DC motor and an encoder, I would not recommend it. A servo motor or stepper+encoder would be much less likely to overrun and would be much better at holding position.
 

SmithDoor

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All motors can over heat. They need cooled and not under sized.
The programming of must include a a slow down at end to prevent over run.

The encoder will hole the exactl spot it does use electrical impulses just a mirror and set of two electric eyes.

The encoders take more programming than just simple using simple pulse.
On printer if lose one or two pulses you not see the error but gear it will make a difference.

Now try calculate the the pulses out for other errors.
The encoder off shelf I can find 5,000 Resolution. The stepper motor off the shelf I found was 1.8 degrees or Resolution of 200.

If great precision use compound indexing.

Dave

While it would be possible to use a DC motor and an encoder, I would not recommend it. A servo motor or stepper+encoder would be much less likely to overrun and would be much better at holding position.
 
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xpylonracer

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Dave, using micro-stepping from the controller will provide as many step pulses as needed to get a resolution of a few seconds of arc.
 

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