My turn for help with Pulse multiplier for test rig.

Ok well not often I'm asking for help but with this kind of electronics I'm not so savy.!

What I want to do is build a SIMPLE test rig for moving machine AXIS around on bench with NO PC involved.

I've got a simple setup already that is just a Drive and MPG and it works ok but hurts my wrist winding MPG more than 3hrs watching Babe Station.:onthego:
(Stuck a drill on it but that is going to kill MPG sooner or later.)

So what I "Think" need is a step multiplier and I want to know the simplest and easist way to do this. Ideally I would like not involve Arduino's or Rasp tarts Etc just keep to simple electronics on simple bread board PCB. (Oh and cheap to build)

That's it really and I haven't got a clue where to start so I'm relying on you Electronic Boff's.!!

Sticking my neck out here but something like this 2MHz DDS Function Signal Generator Module Sine/Triangle/Square Wave+case | eBay I think could drive the drives for a start ..Clive

If you want to get the soldering iron out, a 555 based circuit should do the trick...

555 Oscillator Tutorial - The Astable Multivibrator

Put a variable resistor in for R2 to vary the speed and maybe a switch to change the capacitor if you want more range.

A couple of quid should get you going.

Hi Jazz,
What stepper driver do you use?
The digital drive I use on my mill have a "Test Mode" ... All you need to do is flick a micro-switch on each drive. :-)
Can't do simpler or cheaper than that !

RNR

The AM882 manual has this diagram, and it says

"In order to avoid some fault operations and deviations, PUL, DIR and ENA should abide by some
rules, shown as following diagram: "
Attachment 12157

So will a simple controller also have to obey these 'rules' ?

I'm no expert but I would think you should be able to turn the motor / axis with just a few volts about 12v missing the driver and the PC out altogether Found this on YouTube look as it's a hacked PC PSU, can't get much cheaper than that. Mike
http://www.youtube.com/watch?v=yD4YEwG-3VA

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Originally Posted by longy

I'm no expert but I would think you should be able to turn the motor / axis with just a few volts about 12v missing the driver and the PC out altogether Found this on YouTube look as it's a hacked PC PSU, can't get much cheaper than that. Mike
http://www.youtube.com/watch?v=yD4YEwG-3VA

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I don't think that is what Dean is trying to achieve as it would take forever to move the axis for testing purposes.
He need it to move quickly up and down the axis. But a good demo of the way a stepper moves. Clive

Clive S, that's still quicker than 3hrs mind you he was watching Babe Station so his hand may have been winding the wrong crank LOL. Or for $40 would this do the job, less strain on the wrist! CNC STEPPER SERVO MOTOR STEP Pulse Generator & TESTER Pulse generator [] - $39.99 : Get Hubbed, The Art of CNC

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Originally Posted by longy

Clive S, that's still quicker than 3hrs mind you he was watching Babe Station so his hand may have been winding the wrong crank LOL. Or for $40 would this do the job, less strain on the wrist! CNC STEPPER SERVO MOTOR STEP Pulse Generator & TESTER Pulse generator [] - $39.99 : Get Hubbed, The Art of CNC

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Now that's more like it. ..Clive

Clive there's others that may do what he wants from $25 would Servo/Stepper Testing : Get Hubbed, The Art of CNC or this on ebay http://www.ebay.co.uk/itm/Reversible...item41765abaf1 Mike

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Originally Posted by longy

Clive there's others that may do what he wants from $25 would Servo/Stepper Testing : Get Hubbed, The Art of CNC or this on ebay Reversible Stepper Motor Speed Regulator Pulse Signal Controller stepping 12-24v | eBay Mike

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Well you get the prize, good find.:beer: ..Clive

Only trying to help Clive. Dean has been more than helpful with my cnc build plans and he's kicked me into touch several times LOL... So if I can help I'll try. Mike

I know you said ideally not using an Arduino, but if you want it simple they're hard to beat as the principle of Arduino's seems to make the electronics and coding as simple as possible. The Arduino Uno has 5V outputs, so you can connect it directly to the stepper driver - no other components required.

The timing diagram Eddy's highlighted would be easy to follow with the Arduino, but for this application we don't need to worry about it too much - just set the step pulse width to at least 5us and it'll be fine.

Just to be clear, do you just want to control one motor at a time? For instance just use a potentiometer to set the speed and the circuit outputs the pulse train to get that speed?

(By all meant do it using one of the other ways suggested in this thread - they all look fine to me.)

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Originally Posted by Jonathan

Just to be clear, do you just want to control one motor at a time? For instance just use a potentiometer to set the speed and the circuit outputs the pulse train to get that speed?

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Yes all I want is to Jog one axis at a time for testing purposes so can run machine thru it's travel quickly when no electonics are connected. I've got a spare drive and MPG wheel and just want a cheap way to increase the distance traveled per click, IE step multiplier.

I've got a Raspberry Tart and could use that but don't want to as I want it simple and I've got another use for that.
I could buy drive with Pulse generator built into it but don't want to as I have perfectly good drive sitting here that I'll never fit to a machine.

Currently I've got the MPG connected to the drive and it works fine so I didn't think it would be a massive electronics project or expensive to create a step multiplier just to speed up the travel.?

Thanks to those that pointed out the products that are available to do this and I did know about them but don't want to buy one, I want the experience of doing this and I'm sure it could be done for under a tenner.! . . . . If not then I'll not bother as I've loads of alternatives.

So come on you electronics geeks surely one of you can knock together a simple circuit for a Dummy's to do this.? . . . . . . . If not you'll leave me no option but to go back to Cnczone and ask my Old mates.:hopelessness: . . . . SO COME ON . . lets KEEP IT BRITISH.:loyal:

How much of a multiplier do you need Dean? And fixed or variable multiples? Not hard to do. I'm guessing you want to retain the MPG to give some degree of control rather than an autonomous pulse generator as already suggested?

Someone suggested a 555-based timer, and that's the way I would go as well. Google "555 timer" and there will be plenty of sample circuits - just a half-dozen or so components, bit of Veroboard, and you can probably do it for a fiver. Like this one? I built one of these a while ago when my wife gave me three days - over a weekend - to build a slow-speed turntable to display a piece of work. All I had to hand was a spare stepper from my 3D printer and the matching Pololu driver. All you need to do is generate 5V pulses so run the circuit off any convenient source of 5V; direction can be switched, and enable hard-wired. Timing isn't an issue as long as you get the pulse length above the minimum for the driver.

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Originally Posted by irving2008

How much of a multiplier do you need Dean? And fixed or variable multiples? Not hard to do. I'm guessing you want to retain the MPG to give some degree of control rather than an autonomous pulse generator as already suggested?

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Thanks Irving. Yes would like to keep the detent control of MPG. I could live with Fixed multiplier but would be nice if not too much more trouble.
It's a 100 pulse per turn MPG so at minute it's 2 turns for one Rev of stepper. I mostly work with 10mm pitch screws so it would be nice if one turn = 100mm so say x 20 Multiplier. Idealy 10, 20, 50.

I'd go for something arduino based if you want to have MPG control.
To get smooth motion you need something that can do a little bit thinking and translate how quickly the pulses need generated based on the input, and Arduino gives you the 5V signals, can handle a MPG input, and the clones can be had for not much money.

It's true a software/minimal hardware solution is ultimately more flexible, but Dean wanted a learning experience too.

Dean, can your MPG be set to 1 pulse/turn? Because a pulse multiplier needs to fit n pulses into each pulse from the MPG. If that's producing a sequence of fast pulses followed by a longish gap then a simple add-on hardware multiplier is going to struggle and the software solution is more practical.

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Originally Posted by irving2008

Dean, can your MPG be set to 1 pulse/turn? Because a pulse multiplier needs to fit n pulses into each pulse from the MPG. If that's producing a sequence of fast pulses followed by a longish gap then a simple add-on hardware multiplier is going to struggle and the software solution is more practical.

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No it's only the MPG wheel not a pendent so just one pulse per detent. 100 detents per/Rev.
Like this one. Attachment 12185

Oh ok, that's easier.

Assuming that has a 5v supply and A and B outputs then what I have in mind should work ok :) Do you have a link to datasheet?

What about this?
555 stepper pulse generator

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Originally Posted by irving2008

Oh ok, that's easier.

Assuming that has a 5v supply and A and B outputs then what I have in mind should work ok :) Do you have a link to datasheet?

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Irving, it sounds like this one, there's a data sheet in the download tab, ISM6045 (Hand Wheel)

Sorry irving been busy.

It's one sent to me along with a Pokeys 56E to try out. Nothing special it does have differential outputs so got A+ A- B+ B- and use's 5v.

This one PoMPG1 but no data sheet as such.

No problem. Got a design worked out, uses 3 chips plus a dip switch & a handful of discrete parts. Will give you a multiplier between 1 & 256 set by the dip switch. Careful shopping should easily get under £10 including some stripboard to assemble it on. Will post up schematic over weekend after I've run a couple of simulations on it..

Quote:

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Originally Posted by irving2008

No problem. Got a design worked out, uses 3 chips plus a dip switch & a handful of discrete parts. Will give you a multiplier between 1 & 256 set by the dip switch. Careful shopping should easily get under £10 including some stripboard to assemble it on. Will post up schematic over weekend after I've run a couple of simulations on it..

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Star man I'll fire up the old poker iron in readyness. .:applouse:

Hi Jazz,
What stepper driver do you use?
The digital drive I use on my mill have a "Test Mode" ... All you need to do is flick a micro-switch on each drive. :-)
You may not even need anything made at all.....

RNR

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Originally Posted by rnr107

Hi Jazz,
What stepper driver do you use?
The digital drive I use on my mill have a "Test Mode" ... All you need to do is flick a micro-switch on each drive. :-)
You may not even need anything made at all.....

RNR

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It's an old 752 anologue drive I had kicking around so no such nicety's.

Like I've said I could buy cheap digital drive that will do it or pulse generator board and multitude of other options like Arduino but I have the drive and MPG wheel and know it's only simple electronics to make this happen but I'm not into electronics to that degree to know how or what's needed. I know people who have done this and could approach them but just thought it would be good for the forum and maybe others to see how.

To be honest I'm little surprised( slightly dissapointed) there are not more takers or more informed/detailed suggestions because I know there are plenty on here who do know how or could easily come up with something.!

Hi JAZZ

When I first saw this I thought - 555 - like a couple of others here. But then I saw you really wanted a step multiplier to add to your MPG. IMHO That makes a whole world of difference over a simple step generator.

I see Irving has a plan in motion - I have to say I'll be interested to see it because whilst I think this would be fairly trivial with SOFTWARE, a purely HARDWARE solution - well - like I say I'll be interested to see it.

Just to give an idea of WHY I think there is more to this than might meet the eye. Your requirement was for a 10, 20, 50 MPG multiplier.

So at first site you might say - ok - every pulse that comes out of the MPG let's just generate 10. But what frequency does it output those pulses at? It has to do the 10 before the next MPG pulse - but it has no idea when that's coming. So you either end up with 10 pulses and then some arbitrary gap before the next MPG pulse (I forsee stepper stalling here) OR you end up getting the next MPG pulse BEFORE the 10 have finished. Oops - now we need to buffer the MPG pulses, so now we need memory.

Alternatively your hardware could wait until it's received a few pulses and follow the trend - kinda work behind the curve - again - trivial in software - but to me at least a nightmare in purely hardware.

Add to that the fact that once you get to your 50 x multiplier, maybe even before - you're going to have to start concidering accel ramps etc. etc. - frequency blending...

On the other hand of course I might be completely wrong - but at the moment I can't see it and so haven't offered anything.

If you relent and allow software - then I'll be in. :beer:

Cheers

Ian

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Originally Posted by stirling

When I first saw this I thought - 555 - like a couple of others here. But then I saw you really wanted a step multiplier to add to your MPG. IMHO That makes a whole world of difference over a simple step generator.
Snip...

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My thoughts exactly...

I'll be interested to see what Irving comes up with.

It's quite amazing what can be done with logic chips, however I'm like you Ian, I'd be using software and I'm eager to see what Irving comes up with.
Most of the early Gecko drives relied alot of pretty basic Logic chips, yet Marriss managed to do some pretty cool things with them.

Assuming Dean doesn't require to move the exact number of steps/pulses, then you wouldn't have to be that accurate about timing, and could miss some pulses.
For example, as soon as a pulse is input, output x pulses at a slow rate, then if another input arrives before the x pulses are generated, reset the counter to x and increase the output frequency and so on. That way you're never really behind the curve in terms of number of output pulses, and you don't have to handle buffering/predicting what's going to happen. Off course slowing down is pretty easy, however you may want to implement some kind of deceleration so you're not slamming to a stop as soon as you stop spinning the MPG from high speed.

And from there, you could also add a logarithmic style input, in that the quicker you spin the MPG, the higher the step multiplier is i.e. slow turn could be single step, gradually increasing to 50x at high speed. That way you can still maintain accurate slow speed, yet still move at high speed.

I could probably throw some code together, however I don't have any MPG to try it, and I've also currently not got any spare Arduinos kicking around! (I keep meaning to order some, as I've got a couple more prototypes to build, but that's currently on the roundtuit list!)

...and the only reason that the Arduino-based approach fails to meet the cost criterion is because people think of buying a complete Arduino board. But an Atmega chip only costs a couple of quid (for one of the smaller dual-inline versions) and if someone could develop the code and burn the odd chip or two, it would barely cost more than a 555 with a couple of switches and a pot. In fact, it's the reason that the simpler microprocessors were developed in the first place, to avoid boards full of logic chips. I took this approach recently with a soldering iron temperature controller, but I have too many projects on the go already to put my hand up for this one, I'm afraid. So, watching with interest to see what turns up!

Ex-G8BYK, now G4FBN, and wondering how it would have been done in thermionic valve days...

The more I think about this - the more crazy it gets. A MANUAL pulse generator is exactly that - MANUAL. It allows you to step ONE pulse or MANY pulses under precise MANUAL control. That's it's whole purpose in life.

Earlier, with an electric drill attached. That makes it no longer MANUAL. The MPG became a means to an end. When you pulled the drill trigger, you might just as well have turned a pot.

The MPG is just becoming a distraction. Everything that everyone has suggested (even Irving with the ONE pulse per rev) is battling against the MPG's natural behavior. Whatever ANYONE comes up with it will no longer behave like an MPG - so why have it in there at all?

I reckon your back to the 555.

Sorry - short and to the point - I'm drinking here...

:glee:

Isn't it more obvious to use not electronics but a mechanical step-up?

The standard circuit to multiply a frequency is a phased locked loop and there are ICs that implement it. If I recall correctly they don't handle varying frequency well.

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Originally Posted by stirling

When you pulled the drill trigger, you might just as well have turned a pot.

The MPG is just becoming a distraction. Everything that everyone has suggested (even Irving with the ONE pulse per rev) is battling against the MPG's natural behavior.

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Not everyone - I suggested the pot. back in post #13... However Jazz said he 'would like to keep the detent control of MPG', i.e. be able to move a distance specified by turning the dial, not just set it at a speed and go. Either are easy to do with a microcontroller. The differential signalling very slightly complicates matters. I just suggested Arduino as although I dislike them, it's undeniably easy, but in post #14 Jazz seems to call that a 'massive electronics project'...

In software it is trivial - just stay one pulse behind, measure time (t) between pulses and output pulses at f=n/t where n is 10,20,50. If another pulse not received, output n pulses at your favorite frequency to catch up. But as Irving pointed out 'Dean wanted a learning experience too'.

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Originally Posted by JAZZCNC

To be honest I'm little surprised( slightly dissapointed) there are not more takers or more informed/detailed suggestions because I know there are plenty on here who do know how or could easily come up with something.!

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It's more entertaining to watch and see what other people come up with. Plus I'm busy at the moment with another massive electronics project :glee:, so you'll hear from me if this isn't over in a month or two.

Tbh my approach just generates n pulses for each wheel pulse at a rate that's fast enough to finish before the next wheel pulse. To vary the multiplier pulse rate to adapt for the wheel pulse rate is much more complex and I'd probably start going the software route on that (but not beaten yet). I'm assuming Dean is just testing basic motion and maybe home/limit switches. I haven't provided any acceleration control - it's only 3 chips after all (optional 4th if you want an LED to warn of overrun, ie wheel pulses too fast for multiplier), plus 2 options for multiplier control, a dip switch giving 1 - 256 or a 4 way rotary giving 1, 10, 20 & 50

This might not be what Jazz needs for his project but it might be useful to someone else. https://neil.fraser.name/hardware/stepper/ttl.html

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Originally Posted by Jonathan

It's more entertaining to watch and see what other people come up with. Plus I'm busy at the moment with another massive electronics project :glee:, so you'll hear from me if this isn't over in a month or two.

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ROTFLMAO - Effing unbelievable - That has to be one of the most effing arrogant statements I've seen you come up with to date. It's a doozy.

Hopefully the "entertainment" you get from watching the rest of us neanderthal cretins struggling with the concept of which way is up for one or two months meets with your approval.

:hysterical::hysterical::hysterical::hysterical::h ysterical::hysterical::hysterical:

Ah thanks Matey - you kill me.

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Originally Posted by stirling

Hopefully the "entertainment" you get from watching the rest of us neanderthal cretins struggling with the concept of which way is up for one or two months meets with your approval.

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I agree with Jonathan. Patently you don't understand what it is to be a geek.

From a geek perspective this is a request for a magic box of tricks that performs some nebulous function with a motor by reading Jazz's mind when he plugs it in.

If you think you can make it then you are either an extreme geek or a Neanderthal cretin. There is no middle ground :highly_amused:

Fit a hand crank to the rear stub shaft of the stepper motor.

Attachment 12224