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Messages - wantcnc

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21
General Mach Discussion / Re: Encoder Hacker Needed
« on: March 06, 2008, 02:54:40 AM »
first of all my last post seems harsh, it was not intended to be :-[

in most applications hall effects are used as switches, and thus either a schmitt trigger circuit is added or build-in
with the use of hall effect basically if it moves (as in cyclic) the electronics look at the flank of the signal, if it is not cyclic (like proximity) you look at a "arbitrary" level
and decide stop/move
generally in the electronics world , if you can reduce a real world analog signal into electronic timing signal it is always easier to measure/reproduce then a analog signal level

in order for the this encoder to work (and I was a factor of 10 out) it will have to interpolate to quite a small degree
so take the 50.000 CPR , that's 0.0072 degrees per click, so the positional change of any teeth is minute the change in distance change be teen the sensor and a teeth is even less, The hall effect sensor must thus be able to measure sub 0.001mm distance changes and translate in a proportional voltage level change.
this then has to be captured by the electronics, which if substantially below mV becomes hard to reproduce
this (analog 2 digital) is a large part of my dayjob and it gives me and my co-workers grey hears ..... :'(


Still these motors are cool .....intended
JB




22
General Mach Discussion / Re: Encoder Hacker Needed
« on: March 05, 2008, 02:26:54 PM »
by all mean try it, however

if is was a simple AB encoder  why would the manufacturer not directly interface with the micro, since it has a timer/counter input
further if it is a simple AB, how does it create 5000 steps out of that toothed wheel which only has 60 or so teeth...

as said before my bet is that these are two magnetic sensors, quite likely coils and that they are exited by the custom chip
both are set at a specific distance from eachother and they can both see the same teeth of the wheel, by measuring the loading on the coils induced by the proximity of the teeth, current and timing and smart analog stuff this thing can interpolate the position.

alternatively it is a Hal effect sensor, and they measure the analog level altough that would require extensive calibration and be subject to noise (especially magnetic)

We have been playing with a magnetic sensor to measure current on busbars ( think 400A and above), great idea only the local earth magnetic fields affected the measurements...

A better explanation can be found at the newal site, the sphersyn system


 


23
General Mach Discussion / Re: Encoder Hacker Needed
« on: March 05, 2008, 03:14:33 AM »
judging from the logo on the smaller SMD chip fitted to the board this looks like custom chip jobie

Looking at the tracks I would think it translates the magnetic changes in a similar way as the newal linear encoders
Wetter it is totally passive or actually active is unclear, coolmuscle is not very forthcoming in info on it.
You could look for patents in their name, often explains a lot.

The larger IC is a standard NEC micro which likely deals with the motion and communications

I scoured the net and could find no data in the IC (expected)

interresting product though

JB

24
General Mach Discussion / Re: Emco Turn 120P
« on: March 03, 2008, 05:04:02 PM »
we can all always use help :-)

I have been lucky in that the UK importer send me the diagrams which makes life a lot easier

So far I have removed the DC spindle drive as there was no sensible solution to running it from single phase
The money spend on making 3 phase/changing the DC drive would easily pay for an AC spindle with closed loop control

Stepper wise, well they seem to work (powered it up) Not seen any movement yet as I have remove the controller cards
(intend on sticking mach3 on this thing) if they behave I will keep them, what is odd is that according to the docs, they are set to full step and not halfstep
(bearing in mind these are 5 phase steppers) I would have though this runs at high resolution....

if work does not keep me away from it, I hope to run step/dir signals mid week....
currently I am mapping out the control signals between LPT and a cubloc

what seems odd is that the monitor only has a ribbon loom going to it (with composite signals) and no power ????
so that is why i did not bother firring up the full system.

Getting ahead of myself here I am looking to find tooling for this thing, as the toolholders seem Emco specific, do you know of a source ?

what is your experience with them , do you run them as per "factory setting" or have you converted ?


25
LazyTurn / Re: LazyTurn
« on: February 25, 2008, 04:10:34 PM »
Can I second Graham on the request for scaled backdrop view of the lathe,chuck and tools.
this is by far the hardest thing in turning to keep stationairy and rotating bit away from eachother (about to run a slanted bed machine here with tool turret)
DXF is good enough
imagine a DXF for the lathe, and several others for the tool profile (origin as tool marker)

JB

26
General Mach Discussion / Re: Emco Turn 120P
« on: February 11, 2008, 03:01:40 AM »
Thanks Chip

The machine was wired for 3 phases (UK), The control, stepper system is ran from single phase ( L1 + N ), the spindle drive / oil pump are 3 phase
this would have been connected directly to the main network.

by the looks of things (phase anshnit steuerung) the spindle drive is a thyristor drive which means it needs the 3 phases for the timings (3 controlled rectifiers 1 for each phase)
so either I have to re-create 3 individual phases (much like an AC drive) or somehow send timing signals to a single pair of rectifiers....
I looked at single phase DC drives and they seem quite costly...still some investigation needed.

The plan is to disconnect the drive for now and fire up the system, see what works and what I can raided for Mach control
diagrams would have made it all so much easier...but then I got this at a good price

it is surprising how little info there is on these machines

pics of the control unit, note the 3 pole ABB breaker left of the spindle drive, also note the 3 black wires and blue neutral wire going into the top of the drive

27
General Mach Discussion / Emco Turn 120P
« on: February 10, 2008, 03:21:48 PM »
Just got myself an old emco turn 120P  ;D
when I picked it up I got a shock :o in that it has a large DC spindle, which I did not expect
This motor is a siemens 1GL5104-0EZ40-6JU7-Z  and the drive is the emco one, which seems 3 phase fed.
I would love to keep the motor, so am trying to get info on it, none seems available on the net

Has anyone converted a 120P to mach and retained the steppers and drivers, seem Ok so why waste them?

any info would be welcome
especially schematics as I would happily pay for those....

JB

28
I’m not new new, been around the forum for nearly a year
I am in the process of converting a Warco VMC to CNC control
The current status is that the controller has been build and only needs drives fitting
The machine is now under attack, currently machining the mounts for the motors.

I was born in Holland and moved to England somewhere in 94 for work ( headhunted)
My interest in CNC started long ago
As I helped a guy converting his lathe back in the mid 80 ties  (I did the mechanical work) He used BASIC and a Apple II for control while I was still at school.
Later at the Polytechnic they got a Deckel FPx CNC centre which got used by the teachers. We where kept a long way away from it. (the last 2 years there)
I then set of in a different direction (Stage lighting electronics) so for years no real contact with CNC.
Over the last 10 years I have been more involved in the overall product design.
And thus metalwork is back on my daily agenda, this is mainly sheet metal but I also design machined and moulded parts.
I bought the Warco VMC and a BH600 lathe a few years ago to be able to make special parts and prototypes for work. I also make parts for the observatory, which I have been building for the past 6 years.
My hope is to finish the mill this year along with an enclosure for it.
The next machine on the hit-list is either the Lathe or making a brake press (CNC needles to say)


JB

29
Show"N"Tell ( Your Machines) / Re: Bender
« on: February 05, 2007, 02:50:23 PM »
Amazing piece of kit

Thanks for sharing



JB

30
OK got it working now. as predicted feel a bit silly here

Got the 0V wire wrong on the DC header of the MB, so control logic was floating at 5v...
As soon as I stuck the scope on only it became clear that the signals where working OK, So wire inspection started...


All thanks for helping...




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