PDA

View Full Version : My turn for help with Pulse multiplier for test rig.



JAZZCNC
23-04-2014, 11:13 AM
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.!!

Clive S
23-04-2014, 11:56 AM
Sticking my neck out here but something like this 2MHz DDS Function Signal Generator Module Sine/Triangle/Square Wave+case | eBay (http://www.ebay.co.uk/itm/2MHz-DDS-Function-Signal-Generator-Module-Sine-Triangle-Square-Wave-case-/111325346507?pt=UK_BOI_Electrical_Test_Measurement _Equipment_ET&hash=item19eb81facb) I think could drive the drives for a start ..Clive

FatFreddie
23-04-2014, 12:12 PM
If you want to get the soldering iron out, a 555 based circuit should do the trick...

555 Oscillator Tutorial - The Astable Multivibrator (http://www.electronics-tutorials.ws/waveforms/555_oscillator.html)

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.

rnr107
23-04-2014, 12:57 PM
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

EddyCurrent
23-04-2014, 12:58 PM
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: "
12157

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

longy
23-04-2014, 06:13 PM
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

Clive S
23-04-2014, 06:18 PM
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

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

longy
23-04-2014, 06:26 PM
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 (http://www.hubbardcnc.com/index.php?main_page=product_info&products_id=91)

Clive S
23-04-2014, 06:33 PM
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 (http://www.hubbardcnc.com/index.php?main_page=product_info&products_id=91)
Now that's more like it. ..Clive

longy
23-04-2014, 06:37 PM
Clive there's others that may do what he wants from $25 would Servo/Stepper Testing : Get Hubbed, The Art of CNC (http://www.hubbardcnc.com/index.php?main_page=index&cPath=3_37) or this on ebay http://www.ebay.co.uk/itm/Reversible-Stepper-Motor-Speed-Regulator-Pulse-Signal-Controller-stepping-12-24v-/281158531825?pt=UK_BOI_Industrial_Automation_Contr ol_ET&hash=item41765abaf1 Mike

Clive S
23-04-2014, 06:47 PM
Clive there's others that may do what he wants from $25 would Servo/Stepper Testing : Get Hubbed, The Art of CNC (http://www.hubbardcnc.com/index.php?main_page=index&cPath=3_37) or this on ebay Reversible Stepper Motor Speed Regulator Pulse Signal Controller stepping 12-24v | eBay (http://www.ebay.co.uk/itm/Reversible-Stepper-Motor-Speed-Regulator-Pulse-Signal-Controller-stepping-12-24v-/281158531825?pt=UK_BOI_Industrial_Automation_Contr ol_ET&hash=item41765abaf1) MikeWell you get the prize, good find.:beer: ..Clive

longy
23-04-2014, 06:55 PM
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

Jonathan
23-04-2014, 09:22 PM
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.)

JAZZCNC
23-04-2014, 11:25 PM
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?

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:

irving2008
23-04-2014, 11:38 PM
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?

Neale
23-04-2014, 11:42 PM
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? (http://www.doctronics.co.uk/555.htm#astable) 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.

JAZZCNC
24-04-2014, 12:06 AM
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?

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.

m_c
24-04-2014, 12:18 AM
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.

irving2008
24-04-2014, 02:36 AM
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.

JAZZCNC
24-04-2014, 02:51 AM
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.

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

irving2008
24-04-2014, 08:03 AM
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?

Web Goblin
24-04-2014, 10:26 AM
What about this?
555 stepper pulse generator (http://electronics-lab.com/projects/motor_light/014/)

EddyCurrent
24-04-2014, 10:50 AM
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?

Irving, it sounds like this one, there's a data sheet in the download tab, ISM6045 (Hand Wheel) (http://www.zappautomation.co.uk/en/handwheel-for-cnc/595-ism6045-hand-wheel.html)

JAZZCNC
24-04-2014, 11:12 PM
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 (http://www.poscope.com/PoMPG1) but no data sheet as such.

irving2008
25-04-2014, 12:49 AM
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..

JAZZCNC
25-04-2014, 01:03 AM
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..

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

rnr107
25-04-2014, 11:26 AM
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

JAZZCNC
25-04-2014, 04:06 PM
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

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.!

stirling
25-04-2014, 06:04 PM
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

FatFreddie
25-04-2014, 06:33 PM
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...


My thoughts exactly...

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

m_c
25-04-2014, 06:37 PM
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!)

Neale
25-04-2014, 06:55 PM
...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...

stirling
25-04-2014, 07:26 PM
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:

JohnHaine
25-04-2014, 11:51 PM
Isn't it more obvious to use not electronics but a mechanical step-up?

Jonathan
26-04-2014, 12:43 AM
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.


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.

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'.


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.!

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.

irving2008
26-04-2014, 07:46 AM
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

Web Goblin
26-04-2014, 12:19 PM
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

stirling
26-04-2014, 12:29 PM
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.

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.

Robin Hewitt
26-04-2014, 01:31 PM
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.

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:

EddyCurrent
26-04-2014, 02:07 PM
Fit a hand crank to the rear stub shaft of the stepper motor.

12224

Robin Hewitt
26-04-2014, 04:19 PM
Fit a hand crank to the rear stub shaft of the stepper motor.


That works on so many levels, a complete solution, I am truly in awe :beer:

Neale
26-04-2014, 05:02 PM
That works on so many levels, a complete solution, I am truly in awe :beer:

Almost, but not quite. It just needs a solenoid-operated lever to give the user a slap on the wrist when the limit switch is triggered.

Robin Hewitt
26-04-2014, 05:37 PM
Almost, but not quite. It just needs a solenoid-operated lever to give the user a slap on the wrist when the limit switch is triggered.

Like me you are forgetting Gotama's advice to Siddhartha... "Beware of too much cleverness".

EddyCurrent
26-04-2014, 08:44 PM
When I was about 20 years old my work colleagues presented me with the (fictitious) Duke of Edinburgh Award for 'Use of Stone Age Tools'.

EddyCurrent
26-04-2014, 09:51 PM
Almost, but not quite. It just needs a solenoid-operated lever to give the user a slap on the wrist when the limit switch is triggered.

Or, when the handle stops turning, you've hit the end stops.

irving2008
27-04-2014, 07:38 PM
OK, here's version 0.1 for discussion....

12250

Jonathan
27-04-2014, 09:21 PM
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.

As touched upon earlier, the 'jitter' this adds to the pulse stream will reduce the maximum feedrate somewhat as the motors wont run as smoothly. How much is hard to say, but it could be a problem...


OK, here's version 0.1 for discussion....

Direction required?

JohnHaine
27-04-2014, 11:30 PM
More and more it looks to me that the best approach is a mechanical step-up! Trying to multiply the number of pulses electronically is inherently the wrong way to go.

JohnHaine
27-04-2014, 11:35 PM
Fix the mpg down on a board and mount a larger mdf wheel next to it on an improvised pivot. Use a wide rubber band as a belt . Should be relatively easy to get a 5:1 step up.

Jonathan
27-04-2014, 11:44 PM
Fix the mpg down on a board and mount a larger mdf wheel next to it on an improvised pivot. Use a wide rubber band as a belt . Should be relatively easy to get a 5:1 step up.

Better still, connect the rubber band to the stepper motor to get a closed loop system. I'm sure you'd get positive feedback for that idea ;)

JAZZCNC
28-04-2014, 02:12 AM
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.

Jonathan I'm even surprised you botherd to comment so I thank you for that.!! . . . . . As for your input then I expected no less from you.!!

Sorry to the rest for not replying sooner or keeping track of this but I've been busy all weekend wrestling unfriendly CNC machines.!!

Ok well let me explain again that ALL i want to do is have the axis move, doesn't matter if it misses steps or stops fast etc just move faster than 1 pulse at a time so I can get from one end of machine to other with cranking the handle 1000's a time.
All I wanting is like Irving says to move the axis while working on machines and for setting up limts switches etc. This is why I would like to have the single pulse detent for when close to limits etc. Before that it won't matter if it gets infront or behind with pulses etc and overruns or misses steps etc as I'm not after any accuracy and when I'm getting close to where want to be I'll drop to single pulse. Sure when used to it I'll know how it's going to react to my turning the handle at differant speeds.?

To those that have suggested mechanical options then YES I know this and I can even push bloody the axis if I wanted but that's not what I want so please don't go there anymore it will only take the thread off at tangents.!

Similar with the arduino and software based options, yes I know they are best or easier option and yes I've done some VB and C++ coding so could after cleaning the rust off gone this route and made it happen.!! . . . But again didn't want to. Just want it rough arse KISS approach and to learn from.

555 timer hasn't been ruled out but I would have to have the single step option like the detent of the MPG.

I'm flat out busy at minute but when I have more time I'll look closer at it and ask some folks I know that have done similair things.

But in mean time please keep giving the suggestions but just remember only needs to be simple doesn't need any thing fancy I'm not after accuracy or any kind of CNC pendant.!!

CHEERS:

irving2008
28-04-2014, 11:48 AM
Added option to replace DIP switch with rotary for presetting step multiplier rate.

12259

magicniner
28-04-2014, 11:53 AM
Given the above refined spec with direct ratio not required, rather than a pulse multiplier I'd suggest a frequency generator with the output frequency programmed to ramp up and down quickly but smoothly with the running target frequency output based on the pulse frequency input.
I'm afraid I don't have my PIC programming system set up at the moment, it's all in a box somewhere in the loft :-(
If only I had an Australian Bloke's Shed, then I could have all my toys out at once!

- Nick

irving2008
28-04-2014, 11:59 AM
A possible issue with the mechanical option is potentially the pulse rate the wheel can achieve. One datasheet shows one such wheel has a fixed 800uS pulse per detent, which limits it to 125 steps/sec or 75rpm.

EddyCurrent
28-04-2014, 12:00 PM
This does not directly answer Dean's request but . . .
If I was building cnc machines I would have as a minimum a box with a bob, power supply, 2 x stepper drivers, vfd, all wiring to a bank of terminals to allow easy connection of limits etc.
This would be connected to a PC with a parallel port running Mach3, there would be two sockets mounted on the outside of the box so that by using a flying lead, individual stepper motors could be connected or if the machine used two steppers on X this could also be accomodated.
This system would allow use of a remote pendant or you could use the Mach3 interface to directly enter G0 codes for moving the axes around, the bob would allow connection of limits and home switches for test purposes.

I believe this would cover all the requirements specified by Dean in the most productive and hassle free manner and from what I've read he probably has all the required parts already, unless of course he has some other, not yet revealed, idea for using the minimalistic approach.

FatFreddie
28-04-2014, 02:08 PM
555 timer hasn't been ruled out but I would have to have the single step option like the detent of the MPG.

How about a hybrid system, keep the MPG for fine control but have a button that also injects pulses from a (variable frequency) 555 timer type circuit? Direction is set by the wheel and that is used for fine adjustments but for rapid traverse, the button is used.

Clive S
28-04-2014, 02:21 PM
How about a hybrid system, keep the MPG for fine control but have a button that also injects pulses from a (variable frequency) 555 timer type circuit? Direction is set by the wheel and that is used for fine adjustments but for rapid traverse, the button is used.
Bingo. :applouse: ..Clive

JAZZCNC
28-04-2014, 07:25 PM
I believe this would cover all the requirements specified by Dean in the most productive and hassle free manner and from what I've read he probably has all the required parts already, unless of course he has some other, not yet revealed, idea for using the minimalistic approach.

Yes I do this already eddy, I have a test rig setup with BOB, SS and 4 drives VFD etc so can test a machine is fully working while on the bench but some times I need to move an axis SINGLE axis away from the bench or before all wiring is done IE short stepper wires so I want simple portable unit to do this. Also some times I have more than one machine on the go and at differant stages of build so Don't want to have to lug PC and all the stuff to machine if it's not on the main bench.

cropwell
28-04-2014, 07:46 PM
12260


But in mean time please keep giving the suggestions but just remember only needs to be simple doesn't need any thing fancy I'm not after accuracy or any kind of CNC pendant.!!



How about a USB games controller like this. Mine cost me nowt, uses keygrabber and the biggest hassle was putting the labels on the keys.

JAZZCNC
28-04-2014, 11:40 PM
12260

How about a USB games controller like this. Mine cost me nowt, uses keygrabber and the biggest hassle was putting the labels on the keys.

Nope.!! . . . . Remember NO PC involved.

JAZZCNC
29-04-2014, 12:32 AM
How about a hybrid system, keep the MPG for fine control but have a button that also injects pulses from a (variable frequency) 555 timer type circuit? Direction is set by the wheel and that is used for fine adjustments but for rapid traverse, the button is used.

Yes this is an option and will be my backup if nothing full fulls my perfect needs.

Irving I'm following your design and with some googling I've found it uses a Hex Schmitt trigger, Flip flop and down counter so I'm learning already . .:yahoo: . . . . Now I just need to get my head around what they are and how they play together.

While googling the codes have been showing up with letters on the ends like "BE" or "BCM" what do they indicate.?

Should I start to play with this now and get these bits to play with or will there be more versions so hold off.?

irving2008
29-04-2014, 07:26 AM
Hi Dean,

You wanted a learning experience so I deliberately left some info off the diagram. :)

These chips come in various package formats, the suffix identifies which so decide how you're going to build it and get the appropriate version. If you're breadboard it you need the PDIP package.

I don't foresee any major changes and these chips are only 30p or so so get them. Maybe even a couple of each just in case :)

I do need to consider Jonathan's valid suggestion re direction so there will be a v0.2 shortly.

irving2008
29-04-2014, 07:34 AM
How about a hybrid system, keep the MPG for fine control but have a button that also injects pulses from a (variable frequency) 555 timer type circuit? Direction is set by the wheel and that is used for fine adjustments but for rapid traverse, the button is used.

Yes I'd considered this approach but rejected it as too easy lol, also doesn't truly meet Dean's original criteria.:)

EddyCurrent
29-04-2014, 11:12 AM
Here's another idea.
I used to work on plant where Selsyn Motors were used for synchronisation purposes and remote indication. It occurred to me that stepper motors were very similar so a quick search found this;
Fun with Stepper Motors - Synchronous Operation without Power - YouTube (http://www.youtube.com/watch?v=ux6VdPnbGqU)
No external electrical power required just a crank handle on a spare stepper motor.

JAZZCNC
29-04-2014, 05:00 PM
Here's another idea.
I used to work on plant where Selsyn Motors were used for synchronisation purposes and remote indication. It occurred to me that stepper motors were very similar so a quick search found this;
Fun with Stepper Motors - Synchronous Operation without Power - YouTube (http://www.youtube.com/watch?v=ux6VdPnbGqU)
No external electrical power required just a crank handle on a spare stepper motor.

Ye played with this before and while it will turn another motor on the bench there's no torque obvioulsy due to low current/volts.

JAZZCNC
29-04-2014, 05:10 PM
Hi Dean,

You wanted a learning experience so I deliberately left some info off the diagram. :)

Good man I like a challenge. . Lol


These chips come in various package formats, the suffix identifies which so decide how you're going to build it and get the appropriate version. If you're breadboard it you need the PDIP package.

Yes BB at first then will probably make a better job with a board.


I don't foresee any major changes and these chips are only 30p or so so get them. Maybe even a couple of each just in case :)

I do need to consider Jonathan's valid suggestion re direction so there will be a v0.2 shortly.

Ok there's no rush so I'll wait until everything settles down then just buy a load of bits at same time and I'm sure there'll be plenty of Magic smoke in the air so I'll get spares. . Lol

Not being savy with these electronictrickery gismo's then it's probably technical chip stuff why it's a problem but Won't the drive take care of the Direction just with 5V on the Dir pin.?

Jonathan
29-04-2014, 08:00 PM
Post #48-49: Looks like that was meant as a serious comment - sorry I didn't realise.


Not being savy with these electronictrickery gismo's then it's probably technical chip stuff why it's a problem but Won't the drive take care of the Direction just with 5V on the Dir pin.?

If you apply 5V across the DIR pins the motor will spin one way, apply 0V (or leave disconnected) and it will spin the other way. You could could do that simply with a switch if you're happy for the machine to go in the direction set by the switch, not follow the direction in which the MPG is spun.

JAZZCNC
29-04-2014, 11:33 PM
If you apply 5V across the DIR pins the motor will spin one way, apply 0V (or leave disconnected) and it will spin the other way. You could could do that simply with a switch if you're happy for the machine to go in the direction set by the switch, not follow the direction in which the MPG is spun.

Obviously I know this and thats what I've been doing just with MPG. This is what I've been saying I just want it simple so flicking switch is fine and spinning mpg just for movement. Just I need faster than the single pulse the MPG spins at but still want the abilty to single step when needed.

555 + MPG would work and would probably be simplist but I don't mind playing and want to learn something in the process and so long as Irving or some other kind sole doesn't mind giving directions then I'll wait and see all the options.!

irving2008
29-04-2014, 11:54 PM
if you're ok with a switch for Dir then there won't be a v2 at the mo.

Suggest, if not done already, you download & print off datasheets for chips and get a handle on what each does.

JAZZCNC
30-04-2014, 01:21 AM
if you're ok with a switch for Dir then there won't be a v2 at the mo.

Suggest, if not done already, you download & print off datasheets for chips and get a handle on what each does.

Yes that's fine Irving and yes data sheets already downloaded but not looked at yet.

EddyCurrent
30-04-2014, 10:33 AM
I was thinking about the pulse generator part of the circuit. What about having a small microphone feeding into a high gain op amp with a couple of reverse connected diodes from the output to ground, then another stage to bring it up to 5v.
If you whistled into the mic then the output from the op amp would be a square wave, we used to make guitar fuzz boxes like this yeas ago.
Now combined with a direction switch all you would need to do was whistle a note that was proportional to the required speed.

cropwell
30-04-2014, 11:56 PM
If I weren't bothered by the current limitation I would use a Parker Digiplan PK3, ('cos I have one sitting in a cupboard) 2 buttons and a switch and you have 3 speed travel in both directions. I have also got 3 PK2's in the same dusty cupboard.
.
I have been sparked with the idea of building a test rig with a couple of proximity sensors and dial gauges, just to see how fast you can accurately move the axis repeatedly back and fore, using the drivers intended for the final build. For that I would use an arduino to give a fixed number of steps with different rates and accelerations.
.

I am retired though, so I haven't got the impetus to get up off my fat arse and do anything :indecisiveness:

JAZZCNC
01-05-2014, 12:15 AM
I am retired though, so I haven't got the impetus to get up off my fat arse and do anything :indecisiveness:

How about the impetus being lifes to short even at advanced age so get your fat lazy arse up and live life before the lights go out.!! . . . . If that don't do it then how about just for the sense of achievement and warm fuzzy feeling it gives.:bee:

cropwell
01-05-2014, 01:52 AM
How about the impetus being lifes to short even at advanced age so get your fat lazy arse up and live life before the lights go out.!! . . . . If that don't do it then how about just for the sense of achievement and warm fuzzy feeling it gives.:bee:

Good grief ! you don't arf sound like the missus.
.
I spent the morning on hold with BT while they tried to assert there was no network fault. I have to go back to Stuart Akroyd Glass when they have broadband, to set up an IP camera to monitor their furnace control panel.
.
I spent my afternoon in the workshop making a header tank stand.
.
It's 00:30 and I have just got back from the workshop, setting up a coolant system for my new lathe. Minor problems yet to solve but it is nearly another project ticked off the list.
.
As my arthritis progresses, my mobility restrictions frustrate me as I can't do what I want to do at the pace that I want to do it.
YES I am fat, but you put in the word lazy, not me.
.
Actually Dean, I was more expecting to have my idea about the Digiplan blasted.
.
:highly_amused::highly_amused:

JAZZCNC
01-05-2014, 01:56 PM
Actually Dean, I was more expecting to have my idea about the Digiplan blasted.
.
:highly_amused::highly_amused:

Wasn't really having ago or blasting at you mostly was bit of fun with slight meaningfullness.!! . . . . I'm probably a little touchy regards not living or folks whinging or whining about what are in the grand scheme of life nothing problems as I've got loved ones living on borrowed time with the Big C, lost familiy and 3 close friends in 3yrs to this Evil disease. . . . So if I was curt then I'm sorry didn't mean to be.!! . . . . . But the message is the Same GET OFF YOUR ARSE before it's too late.!!
The word Lazy was implied by your definition "get up Off my fat arse" doing nothing "Sloth" is lazyness.!! . . . ("Fuck" I'm sounding like Jonathan now so I'll stop)

Nah THEN. . Back to this Digiplan Crap. . Lol . . . . Nah I'll leave this one here. . :thumsup:

_chris_
20-06-2014, 07:09 PM
The easiest solution I can think of is a higher count encoder.