Arduino Rotary Table MEW 249

[Neil WyattModerator @neilwyatt]

Posted by Roger Williams 2 on 16/02/2017 10:50:58:

Hello all, just done Silly Old Duffer's LCD Push Button sketch, added 100 to the figures as per Gary Liming, but still the same glitch,….Run mode CW direction goes wrong way on the initial Left button press, then corrects itself after that. . Step, Angle and Jog are perfect !. Must be doing something wrong somewhere.

One thing I have done when re-programming the Arduino, was to make a hole in the box to connect up the USB cable , so much easier than disturbing everything.

Is your stepper wired up correctly?

Neil

[SillyOldDufferModerator @sillyoldduffer]

Posted by Roger Williams 2 on 16/02/2017 10:50:58:

…but still the same glitch,….Run mode CW direction goes wrong way on the initial Left button press, then corrects itself after that. . Step, Angle and Jog are perfect !. Must be doing something wrong somewhere.

…

Hi Roger,

I looked at Gary's code and can't see anything obvious that would cause those symptoms. I can't think what would cause the behaviour you're getting – it's a puzzle.

However, for the project to work all the ducks have to be in a line. Possibly something small is adrift. It's worth checking everything.

• Most step motors seem to do 200 steps per rotation (ie 1.8° per step) but not all of them. If your motor is different, you will need to change a line near the front of Gary's program. It says: #define StepsPerRevolution 200 // Change this to represent the number of steps

• The next #define says how many micro-steps the controller must be set to: it's expected to be 8. The switch settings on the controller board need to be in the right combination to match the program. It's easy to get these switches wrong, for example upside down, or right to left.

• The controller also uses switch combinations to match the controller to motors of different powers. My motor misbehaves if these are set lower than 3.2Amps. Again, this setting will vary depending on the motor used. It might be worth starting with the maximum setting and working down to see if one of them fixes the problem.

• Finally, as Neil points out, the wiring has to be spot on. As the connections make a decent sized rat's nest, it's not difficult to misplace some of the wires and cause odd effects! I did despite careful colour coding.

I'd post a photo of my DIP switch settings except my controller is not the one recommended by Carl. Judging by comments others have made about the proper controller, my switch layout is different. Although it works for me, it's not a good reference.

Good luck,

Dave

[Roger Williams 2Participant @rogerwilliams2]

Neil Dave, I will go back and check everything. Ive set the Dip switches to the same as Carl apart from lowering the current slightly, to 2.2 amps I think to lower the vibration, so perhaps I will try it a bit higher. Im pretty sure the motor wiring is correct, but it will get checked again.Its just odd that pressing the Left switch twice corrects the Run mode. Many thanks all.

[Matthew DurnfordParticipant @matthewdurnford60824]

Apparently stepper motor torque is reduced if you use microstepping modes. The link below is to a paper describing this :

http://static.micromo.com/media/wysiwyg/Technical-library/Stepper/6_Microstepping%20WP.pdf

My setup is what looks like a Vertex rotary table from Warco with a 90:1 reduction. I have set Microsteps to 1 and the dip switch on the motor controller to no micro stepping. In my case the number of pulses for a full revolution of the table is (90 times 200) 18000 which provides sufficient accuracy at least for my needs but may enable reduced driving current for the stepper motor.

I have also reduced the pulse width to 1 which speeds things up a bit.

If you use a temperature feature then it looks like the code was originally written for a sensor that was calibrated in degrees Fahrenheit rather than Centigrade.

Matthew.

[doogyParticipant @doogy]

Hi all, I was hoping one of you fine gentlemen could shed light on a problem I'm having with my setup

Using the motor to drive a spindexer with a 6to1 ratio, the build and electronics all went well no nasties! and the setup works fine until I try any division or angle less than 30 degrees. For each push of the button it looses maybe 1 to 2 steps ending in quite a significant error on a full rotation, reversing the direction back to the start point and the error is corrected.

I have used every combination of micro stepping and no micro steps, nearly worn out the switches on the Arduino!!! but still the same result. Any thoughts would be greatly appreciated.

Cheers Kev

[John Stevenson 1Participant @johnstevenson1]

Been following this thread on here and similar ones on CNC Zone, HMEM and MEM, often the same people posting and from what I can see far more people are having problems than the few who have actually got one working ?

I think the whole attraction in these controllers is the fact they use a £10 Arduino controller but when I wanted a spare to back my division master unit up [ I rely very heavily on this ] I bought a pre made board from Steve Ward over at World of Ward.com

For £38 all built and tested. Just added a cheap keypad and put it in a box and it works flawlessly.

Now unless your hobby is Arduino's or pi$$ing about life is far to short to get something second rate just to save a tenner.

[Mike PooleParticipant @mikepoole82104]

I put my Ward controller together and it worked first time, does what it says on the tin. Straightforward to use and performs well. If I needed another I wouldn't hesitate and highly recommend. I chose the Ward controller from the available options and it has done what I hoped for and some. After 44 years in electrical and electronic control systems I don't think we need to reinvent the wheel, if someone has done all the hard work and makes it available at a very reasonable price it makes sense to just buy it. I had a manager who was not an engineer who wanted us to make an automatic guided vehicle (AGV) as a competitor had done so, we explained that all the problems had been solved by other people and it wouldn't make sense to spend a lot of money to build something that had already been done, he came around in the end.

Mike

[doogyParticipant @doogy]

Posted by John Stevenson on 04/03/2017 22:31:09:

Been following this thread on here and similar ones on CNC Zone, HMEM and MEM, often the same people posting and from what I can see far more people are having problems than the few who have actually got one working ?

I think the whole attraction in these controllers is the fact they use a £10 Arduino controller but when I wanted a spare to back my division master unit up [ I rely very heavily on this ] I bought a pre made board from Steve Ward over at World of Ward.com

For £38 all built and tested. Just added a cheap keypad and put it in a box and it works flawlessly.

Now unless your hobby is Arduino's or pi$$ing about life is far to short to get something second rate just to save a tenner.

Interesting comment! Now I appreciate that you would rely on such a device in your workshop but I feel a significant majority of us pick a project like this to further understand numeric/computer control of a process. I personally would rather push a button than furiously crank a handle(was that 6 or 7)/run round a tree buck naked/find a copy of my mam's birth certificate then remember to lock the bu##ger down. The fun is working out the problems, frustrating at times maybe, but certainly not to save a few quid or to spend time pidlin into the wind.

Kev

[SillyOldDufferModerator @sillyoldduffer]

Posted by doogy on 04/03/2017 20:50:48:

 

…

Any thoughts would be greatly appreciated.

Cheers Kev

Hi Kev,

It's unlikely to be the software. One cause of skipping is that that power supply can't provide the current needed to step the motor reliably under load.

• To protect the motor, the controller uses DIP switches to limit the amount of current it will pulse into the motor. Are these set too low?
• Regulated power supplies aren't recommended for this application because the motor can push volts back into the PSU. This can cause the PSU to back-off or even shut down. A simple transformer / bridge rectifier / capacitor supply may be better than a more sophisticated unit like a computer or LED strip PSU .
• Step motors are worked by short pulses of current rather than a simple volt x amps relationship,. They test the PSUs ability to satisfy a peak demand rather than the much lower average. A capacitor across the PSU's output terminals may help. One formula recommends 80000 * I / V uF which seems a lot. I have a 12v 3A supply, which would be about 20,000uF, assuming it didn't already have a capacitor inside. Not very critical, I feel: I'd try 2 or 3 4700uF or 3300uF electrolytic capacitors in parallel; they're about 50p each from Maplin.

Hope you get it working!

Dave

Edited By SillyOldDuffer on 05/03/2017 13:35:59

[HowiParticipant @howi]

Posted by doogy on 05/03/2017 13:02:39:

Posted by John Stevenson on 04/03/2017 22:31:09:

Been following this thread on here and similar ones on CNC Zone, HMEM and MEM, often the same people posting and from what I can see far more people are having problems than the few who have actually got one working ?

I think the whole attraction in these controllers is the fact they use a £10 Arduino controller but when I wanted a spare to back my division master unit up [ I rely very heavily on this ] I bought a pre made board from Steve Ward over at World of Ward.com

For £38 all built and tested. Just added a cheap keypad and put it in a box and it works flawlessly.

Now unless your hobby is Arduino's or pi$$ing about life is far to short to get something second rate just to save a tenner.

Interesting comment! Now I appreciate that you would rely on such a device in your workshop but I feel a significant majority of us pick a project like this to further understand numeric/computer control of a process. I personally would rather push a button than furiously crank a handle(was that 6 or 7)/run round a tree buck naked/find a copy of my mam's birth certificate then remember to lock the bu##ger down. The fun is working out the problems, frustrating at times maybe, but certainly not to save a few quid or to spend time pidlin into the wind.

Kev

I have been into electronics/computers for longer than I care to remember, punching in someone else's code and then complaining that it don't work, is not in my opinion, understanding the basics.I can understand enough of Arduino, PIC and others to understand what is going on and to some extent alter the programming to meet my own ends, but what is the point when someone else has done all the hard work and it works out of the box. My requirement was to get a working stepper driven rotary table. There is of course the commercial unit Division Master for those that have deep pockets and want an off the shelf solution, or there is Steve Wards design that is easy and cheap to make or buy ready made if you must, there is no need to program the Pic chip (even though I have the capabilities) as it can be supplied ready programmed. I did not use the driver board suggested but selected one of many on Fleabay from China that had a much more up to date spec for not a lot of money. A laptop power supply provides the power and a diecast box from Maplin to put it all in. It could all have been done cheaper but as it was not in any way expensive as it was, I did not see the point. It all worked a treat once I remembered to ground the other side of the open collector interfaces ( just me rushing!). While I did think about using an Arduino instead of going down the Steve Ward route, I thought what the neck, there is no point. As good and easy as the Arduino is, it IS NOT necessarily the best tool for the job. We can see this in the problems people have had when not using the same push button setup. Not what you want when you don't really understand what is going on. You then start to think that there should be a better solution than this and that perhaps the Arduino is NOT it. If you want to see another example of where the Arduino has been used but has proved to be not as capable as it's original sibling is the Android DRO project on Yuri's forum. This followed a similar path where people had or could understand ( or thought they could!) an Arduino board, but is just not as capable as the original conception. It is horses for courses in my opinion, and while reinventing the wheel may appeal to some ego's, in reality it just does not make sense (my opinion again!)

why spend hours of frustration and then proceed to moan about it, when a solution is already at hand, it is just not logical.

[doogyParticipant @doogy]

Hi Dave, many thanks for your suggestion, yep I've set the dip's for the motor. Certainly will try capacitor route and let you know the outcome. Hey the worst case is I'm 50p down and a little wiser. Cheers

Howi, dont see anybody moaning or complaining, understanding the basics yep I'll give you that but personally I'm here to try and rectify that and sure others are here to do the same. It's a real lucky person who can learn a thing without a bit of head scratching or frustration. You might be able to determine that Arduino is not the best solution personally, to date, I dont. So if you think wer'e missing something fill us in.

[doogyParticipant @doogy]

Hi Dave, many thanks for your suggestion, yep I've set the dip's for the motor. Certainly will try capacitor route and let you know the outcome. Hey the worst case is I'm 50p down and a little wiser. Cheers

Howi, dont see anybody moaning or complaining, understanding the basics yep I'll give you that but personally I'm here to try and rectify that and sure others are here to do the same. It's a real lucky person who can learn a thing without a bit of head scratching or frustration. You might be able to determine that Arduino is not the best solution personally, to date, I dont. So if you think wer'e missing something fill us in.

[Nick Clarke 2Participant @nickclarke2]

Hi, I have read the last few posts and to my mind, building the indexer from scratch, so to speak, has been a fun and interesting experience, I learn't a bit about Arduinos, I learn't a bit about programming and about stepper motors, drivers etc. It didn't work as expected, but with a little research on t'internet and some help from the good folks on this forum, it now works a treat and I can cut the gears for my Aermotor build. I would not have enjoyed the experience any where near as much had I just bought one. For those of us who are new to black magic, (ie the mysterious world of digital machinery) constructing such a device is educational and satisfying when it all falls into place and does as it should. Minor failures are part and parcel of our hobby, as, at the end of the day, hobby it is, and it can be as much or as little as we want it to be. So for those that shy away from electronics, have a go, you will be surprised, for those that don't, buy a ready made unit, or keep the brain cells excercised and carry on with indexing plates……

[Neil WyattModerator @neilwyatt]

I've tweaked the thread title a bit as 95% of this thread is discussion and teh wrong part number is just the first handful of posts. Nothing deleted.

Neil

[SillyOldDufferModerator @sillyoldduffer]

Posted by Howi on 05/03/2017 13:51:02:

Posted by doogy on 05/03/2017 13:02:39:

Posted by John Stevenson on 04/03/2017 22:31:09:

Now unless your hobby is Arduino's or pi$$ing about life is far to short to get something second rate just to save a tenner.

…

why spend hours of frustration and then proceed to moan about it, when a solution is already at hand, it is just not logical.

Well chaps, you've just denounced the entire hobby.

LBSC spent a lifetime designing, building and running model locomotives and now we find he should bought a bike instead. Those blokes on the forum doing up old bangers – clearly insane; they could buy a nice new car and go and watch TV. James Watt and steam, complete waste of time – the idiot should have bought a horse.

I do what I do with technology for lots of different reasons. One of them is enjoyment – surely that's justification enough.

Cheers,

Dave

[Mike PooleParticipant @mikepoole82104]

I fully support making anything for the experience and pleasure of making it but sometimes it makes sense to take the easy route. As we have a workshop we can have a go at making most things and sometimes it can be an interesting diversion, but if we require a tool it often makes sense to buy one and get on with the main project, if we cannot afford the tool but can make it then this has to be the route to go even if it is a diversion from the main project. Everybody has their own reasons to make something, I had a suitable stepper motor and together with the Steve Ward components it soon turned into a shortish diversion that didn't use to much time and resulted in a useful tool to get on and make the things I actually want.

Mike

[duncan webster 1Participant @duncanwebster1]

+1 for Silly Old Duffer. Doing something new out of my comfort zone keeps the grey matter going. If you just want say a 5"g loco the easiest and cheapest way is to buy one, don't mess with all those machine tools etc

[HowiParticipant @howi]

Judging by some comments on here, I must have lost the plot somewhat. What electronic knowledge is required to plug a ready made display/keyboard shield into a ready made Arduino board?

With the Steve Ward design you can make the PCB, source your own components, program your own Pic chip, even make up your own keypad if you were so inclined, with a variety of other options.

I, for one , do not advocate going out and buying a ready made unit when I can make one, but some do (nothing wrong in that, if that is what you want!), but plugging ready made modules together, loading ready made software, is not to my mind, electronic construction.

The limitations of the Arduino solution are glaringly obvious when you compare to the other existing options.

I have no particular axe to grind with respect to the Arduino in fact the opposite, I have enjoyed playing around with the Arduino platform. BUT! It is not necessarily the BEST solution for everything.

[Roger Williams 2Participant @rogerwilliams2]

Silly Old Duffer, well said. I went the Arduino route because it was from an article in a magazine, no other reason. I learned a lot along the way, and it works. I probably wont use it much, but hey ho !. IF I had needed it to make me lots of money, I would have just bought a Divisionmaster. I might even make one of the Steve Ward ones as well, just for something to do . I just enjoyed the project like a lot of other people.

On the other hand, why p*ss about making a model, just go and buy one because the fuhrer says so……

[Carl Wilson 4Participant @carlwilson4]

One more time for the hard of understanding who inhabit this forum.

I had a need for auto indexing. I wanted a quick easy solution. I went with the Arduino and plug in boards option. It occurred to me that this was a good example of how electronics could be demonstrated to have solved a workshop need, and could be implemented in a straightforward way by those with little prior knowledge. I then wrote up what I did.

I didn’t anticipate the troubles with different cards being used together. Mine
worked first time.

I’d hoped, vainly it now seems, that my little bit of altruism would be seen as an attempt to prove that electronics can have a place in anyone’s workshop and that you don’t necessarily have to make a large time or financial investment to get something done.

I know the reason for a lot of the bitching, of course. It’s because some are not happy unless every MEW article is concerned with the construction of widget to make turning those new fangled Whitworth threads so much easier on your treadle operated Drummond model B.

My next offering for MEW will be a mechanical testing machine involving hydraulics, electronic extension measurement and force measurement sent to a logging computer via an RS232 link. The computer will display the results on a GUI built using labview.

A word to the detractors. Your mealy mouthed utterances have just made me stronger.

[Carl Wilson 4Participant @carlwilson4]

I’m hoping the RS232 link will please the traditionalists. It’s ancient technology.

[John Stevenson 1Participant @johnstevenson1]

Be better if you used Morse

[Neil WyattModerator @neilwyatt]

Can we have RS422, please? Some readers have very long gardens with workshops at the end

Neil

[Neil WyattModerator @neilwyatt]

Here's some big news for the flat-earthers… captured during a recent Lunar eclipse:

[Mike PooleParticipant @mikepoole82104]

"You don't want to do it like that" (Harry Enfield)

Mike

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