Author Topic: X AXIS Driver  (Read 6751 times)

Offline Bluechip

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X AXIS Driver
« on: September 09, 2012, 11:39:11 AM »
Driven by a H-Bridge on the end of a PIC 16F886.
PIC code done in HiTech C
Finally managed to get the damn thing to ekkle..... :scratch: ..   or very nearly. :palm:   
First version allowed direction changing at max rate ... not a good idea, I found.
Frightened me to death once or twice. So now the code has some interlocks poked in there.
But the original PCB didn't suit, so another made ... wrong ... so the third does actually work ...
Does it ever end ???
 

Just found out it doesn't stop, so I realise I've left a....
DO { xxx } while ( run_switch == 1) off  the code ...  :zap:
Sorry it's on Photobufferin'
And it ain't that noisy either ...
 
Dave
 
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Offline kwackers

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Re: X AXIS Driver
« Reply #1 on: September 09, 2012, 05:15:38 PM »
IME you should fit a programming socket to the casing to save dismantling it when you need to tweak the code.

Software is never finished, you simply get bored of adding new features.

Offline HS93

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Re: X AXIS Driver
« Reply #2 on: September 09, 2012, 07:55:23 PM »
That sounds great any chance of a bit more info on how it is made please

peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline Bluechip

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Re: X AXIS Driver
« Reply #3 on: September 10, 2012, 05:39:41 AM »
EDIT ooops ... not DMIOM    :palm:  Hi  Kwackers  Yes, it should have a ICSP socket.  :palm:  No excuse for not having one, the PORTB pins used for ICSP are not used ... neither is the RE3 [?] pin .... bu99er, yet another PCB ......  :Doh:
Peter .. what, like a build log ??? Can do one if you want. Gotta take it all to bits this aftrenoon to get the PIC out and reprogram it ..
Piccys if you want them, except if I do any of the copper side of the PCB's they're crappy. No idea how to get rid of the reflection ...  :scratch:  tried it before ...
Off now doing a 'hunter gatherer' act at Sainsburys. Either that or starvation ...  :lol:
Dave BC
 
 
 
« Last Edit: September 10, 2012, 03:36:32 PM by Bluechip »
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Offline Bluechip

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Re: X AXIS Driver
« Reply #4 on: September 10, 2012, 02:10:21 PM »
Here you are Peter ... piccys

Bottom left is a 15 0 15 transformer, far too big for the application, but it was hanging about doing nowt so it got butchered and nailed in. Edgewise is a Full Wave TO247 rectifier to a 4700uF 35VDC cap. gives some 22VDC offload.

H-Bridge PCB

The 22VDC is fed to a pair of 78S15 regulators paralleled off and jacked up with a 180R resistor in the ground connection to give some 17VDC to the motor h-bridge. Also on that h-bridge board is a 7805 for the PIC supply and a 7812 for the fan.
Also a comK and a comA dual diode for back emf supression. (  bottom right ).
The two DIL8 chips are TC4426 & TC4427 MOSFET drivers as a buffer between the PIC and the MOSFETS.

Processor PCB

Just a PIC 16F886 and a ULN2803A to drive the LEDs. Plus a few resistors to limit LED current.
edit just thought .... can do a layout piccy ..

Last  is a snip of the H-Bridge silk screen .. shows the components.
No it ain't. Last is a snip of the copper side, crap image, the actual print offf the laser is much sharper ..
 
« Last Edit: September 10, 2012, 02:50:44 PM by Bluechip »
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline John Rudd

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Re: X AXIS Driver
« Reply #5 on: September 10, 2012, 05:05:19 PM »
BC,

Very impressed.... :bow:

Not very often I see well executed projects...

What pcb cad program do you use to create your boards?
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Bluechip

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Re: X AXIS Driver
« Reply #6 on: September 10, 2012, 07:29:21 PM »
Thank you, kind Sir. Cheque's in the post ...  :lol:
PCB is done with ExpressPCB. If you look up Eric's thread re: PCB Layout the download link is in there.
I like it. Nice and simple to use. Does for me. Easy to make custom components etc. IIRC I had a reasonable grasp of doing a basic PCB in about a couple of hours.
No doubt it isn't as professional as Eagle, but I don't need that level of performance. Nor is the free version limited to number of holes/PCB size ..
Have a bash at it. Costs nothing. If you don't like it, dump it.   :thumbup:
I have never seriously tried to use Autorouters to develop a PCB from a schematic. Easy enough by hand .. for any stuff I'm likely to do anyway.
ZZZZZZ's time. Seen enough of today, or rather yesterday ...
Dave BC
Found the link for you. While having my Glen Morangie  ... two hours overdue I might add ..  :beer:

LINK  http://expresspcb.com/
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline HS93

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Re: X AXIS Driver
« Reply #7 on: September 10, 2012, 09:08:09 PM »
Tank you for that, so what wa the cost to get a board made by them and how long did it take I have a machine I would like to fit it to,or if you hve any spare boards you might want to sell I am ok with a soldering iron still .

thanks for posting al the information

Peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline Bluechip

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Re: X AXIS Driver
« Reply #8 on: September 11, 2012, 04:50:21 AM »
Peter
I make my own PCB's .. sometimes successfully ... :ddb:
As a rough guess the h-bridge PCB cost some 15 - 20 for the laminate and components.
The processor PCB  some 8 or so for the same.
Probably more expensive than a Chineeeeeese version, but this is fixable if ( when ) it goes pop ....
I doubt if it would suit another application. I was designed ( ??? ) around that Maxon geared motor. It is 36VDC but goes way too fast on that, so I run it at some 17VDC max, which puts it somewhere near right.
So, unless you have another motor the same or very similar, it won't work properly.
In fact, that set up will only be OK between some 8-18VDC. otherwise the 5VDC to the pic will be at risk below 8VDC ( 7805 input dropout ) and the TC44xx are 22VDC absolute max ( IIRC )
Dave BC
 
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Offline HS93

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Re: X AXIS Driver
« Reply #9 on: September 11, 2012, 05:29:10 AM »
Ok thanks for that would this motor do ?

http://www.ebay.co.uk/itm/300511267976?ru=http%3A%2F%2Fwww.ebay.co.uk%2Fsch%2Fi.html%3F_from%3DR40%26_nkw%3D300511267976%26_rdc%3D1

they are a good powerfull motor the advert says they are 12 volt but when you look them up it says 24v we all runthem on 24v. I have fitte plenty in big boats and at 15 to 24 volt they are fine get a bit warm with a big prop after a few hours so short bursts you should even be able to take them up a bit


Peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline Bluechip

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Re: X AXIS Driver
« Reply #10 on: September 11, 2012, 07:16:26 AM »
Ok thanks for that would this motor do ?

http://www.ebay.co.uk/itm/300511267976?ru=http%3A%2F%2Fwww.ebay.co.uk%2Fsch%2Fi.html%3F_from%3DR40%26_nkw%3D300511267976%26_rdc%3D1

they are a good powerfull motor the advert says they are 12 volt but when you look them up it says 24v we all runthem on 24v. I have fitte plenty in big boats and at 15 to 24 volt they are fine get a bit warm with a big prop after a few hours so short bursts you should even be able to take them up a bit


Peter

Can't really say, at a guess no. Why ??
The PCB traces are for a max current of 4A. That motor could take much more than that.
Going back to my antics ..
The motor I have is a motor / gearbox assembly. The reduction ratio is some 5:1, I suppose there is  epicyclic in there but not certain. The belt reduction is about 3.5:1, can't be sure now. So I have a total reduction ratio of roughly 17.5:1 from motor to l/screw.
My WM16 has a l/screw of 10 TPI.
I wanted a max rate traverse rate of some 0.5" / sec on full volts, so that's 5 revs / sec. or 300 rpm.
Taking the belt drive reduction into account, I need about 1000 rpm on the output shaft.
So, fired up my variable PSU, I find 17VDC gives that rpm. No load current some 380mA.
There was an alloy tooth belt pulley on the motor, whipped it off and machined off the teeth. Now have a smooth disc on the shaft.
Wound it up at 17VDC and grabbed the disc (  :loco:  ) to put some load on it. Now current is about 1A.
Never did a locked rotor measurement, but the resistance of the armature suggest a current of some 13A at 17VDC.
So now I have some idea of the motor characteristics.
The rest of the contraption is designed with this info. in mind.
If I started with the motor you posted, then it would be back to square 1 almost.
The circuit I have could be modified for a 12VDC motor by replacing the 78S15's with 78S12's and eliminating the 180R resistor. So the voltage would be correct but I doubt if it would have the capacity to deliver the current without potentially destroying the PCB traces. The 22VDC supply on mine has a 2A Quick Blow fuse inserted in the output. Hopefully, if ( when ) I lock the damn thing up, the fuse will rupture before the PCB .. One can but hope.

You would have to obtain the motor and find out what it really does electrically for the application you want it to do.

Not very helpful ... :(
Dave BC
 
 
 
 
 
« Last Edit: September 11, 2012, 07:56:51 AM by Bluechip »
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline HS93

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Re: X AXIS Driver
« Reply #11 on: September 11, 2012, 07:31:07 AM »
ok thanks for all that, ill stick to steppers.

peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline Bluechip

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Re: X AXIS Driver
« Reply #12 on: September 11, 2012, 08:21:32 AM »
ok thanks for all that, ill stick to steppers.

peter

 :)  Don't blame you .... OK with a decent motor.
That was what I did first. I have some 4.5V 180 step/rev motors but they are not very frisky.
Could not get them to run on load at less than 4mS / step. ie some 1.4 rps on the l/screw ...
Took for ever to get from one end to the other ...X-axis is 720mm on mine IIRC ..
Dave BC
I have a few modest talents. Knowing what I'm doing isn't one of them.

Rob.Wilson

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Re: X AXIS Driver
« Reply #13 on: September 14, 2012, 10:19:52 AM »
 :clap: :clap: :clap: :clap: Clever old bugger  :thumbup:

Looks like it works a dream  Dave  :zap:



Rob

Offline Bluechip

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Re: X AXIS Driver
« Reply #14 on: September 14, 2012, 11:47:33 AM »
:clap: :clap: :clap: :clap: Clever old bugger  :thumbup:

Looks like it works a dream  Dave  :zap:



Rob

Are you back in UK ??? 
Ah well. All good things must end I suppose...  :lol:
Anyway, now you're back let's have some respect.
Less of the 'clever' if you don't mind ....  :scratch:  I have my reputation to think of.
 
Dave BC
I have a few modest talents. Knowing what I'm doing isn't one of them.

Rob.Wilson

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Re: X AXIS Driver
« Reply #15 on: September 14, 2012, 12:02:12 PM »
 :ddb: :ddb: :ddb: I am back in the UK  Dave ,sadly i had to come back only had a few days left before my passport ran out  :palm:


Had to eat your sausage , woke up at 5am on the Berlin to Paris sleeper feeling peckish , was tasty  :)

Rob


Offline Stilldrillin

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Re: X AXIS Driver
« Reply #16 on: September 14, 2012, 12:09:27 PM »
:ddb: :ddb: :ddb: I am back in the UK  Dave ,sadly i had to come back only had a few days left before my passport ran out  :palm:


Had to eat your sausage , woke up at 5am on the Berlin to Paris sleeper feeling peckish , was tasty  :)

Rob

Aaaawwww......... Rob!

Good job you bought him a stick of rock.   :thumbup:

You did....... Didn't you?   

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bluechip

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Re: X AXIS Driver
« Reply #17 on: September 14, 2012, 12:23:19 PM »

Had to eat your sausage , woke up at 5am on the Berlin to Paris sleeper feeling peckish , was tasty  :)

Rob
Never mind, Rob ... just think of this ..
You, on a freezing morning, outside, frozen to the marrow. Working away.... paying tax... which pays my pension.
And I'm snuggled under my duvet, sweating but determined to stick it, laughing away at you ...  :lol:   :lol:   :lol:   :lol:   :lol:
Stuff yer sausage ...   :lol:   :lol: where it's got no chance of a suntan .. :lol:   :lol:
 
Dave BC
 
 
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Rob.Wilson

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Re: X AXIS Driver
« Reply #18 on: September 14, 2012, 12:26:26 PM »
 :lol: :lol: now i dont feel guilty about eating the rock as well  :lol: :lol: :lol: :lol: :lol:


Rob

mumble mumble back to work Monday  :bang:

Offline Bluechip

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Re: X AXIS Driver
« Reply #19 on: September 14, 2012, 07:21:07 PM »
mumble mumble back to work Monday  :bang:
Nope, not for me. Don't think I'll bother .....  :coffee:
BC
I have a few modest talents. Knowing what I'm doing isn't one of them.