Fingers crossed it'll cut ally

The 7700kv motor is only for use in my model car!

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Originally Posted by blackburn mark

i didnt realise it was mentiond in this thread :whistling:

also irving came up with ideas but again its all a bit rocket science to me at the moment

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Yes modifying the servo tester is a good way of doing it. The problem is we'd need no know what the pot is connected to first..i.e the circuit diagram of the servo tester. I don't have any servo testers so I can't really help there yet.

The servo tester could be as simple as the one here:
http://pcbheaven.com/wikipages/How_RC_Servos_Works/
(There's some good info there on how servo signals work. It's the same for the ESC so worth reading.)
In which case you can't easily change the pot.
Maybe open up your servo tester and take a picture...

Going back to the connecting the parallel port directly to the ESC idea, I must just be explaining it badly.

Have you got a multimeter/voltmeter?
If so connect it between the pin you want the spindle on and ground on the parallel port. Set the spindle to full speed in Mach3 and check that the voltage is around 5v (definitely no more than say 5.5v).

If that's the case then for testing purposes just get two bits of wire, connect one wire from the ground (black/brown) wire on the ESC 3 pin connector to ground on the parallel port (any pin from 18 to 25). Connect the other wire from the output pin on the parallel port to the signal wire on the 3 pin connector (white/yellow/orange). DON'T connect anything to the red wire on the 3 pin connector.

From there just try the settings I mentioned earlier in mach3 and see what happens. I'm sure it'll become clearer once you've got it connected.


Do you use anything like windows messenger/Skype etc? If so that could be an easier way for me to explain this.

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Maybe open up your servo tester and take a picture...

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Attachment 3353Attachment 3352Attachment 3351Attachment 3350

dont know if you will make any sense out of these... its just a magic box to me :eek:

i do have a mulimeter but the pc with mach on it is in bits ready to go in my base but i will take you up on the offer of help when i get to that point in the build, iv only had a quick play with mach up to now.

iv just orderd a "MICRO MAESTRO 6-CH USB SERVO CONTROLLER ASSEMBLED" £12 ebay
im not sure if it will solve our mach spindle problem but i thought id give it a punt
Attachment 3356Attachment 3354Attachment 3355
im hoping mach will know what to do with it :question:

micro maestro 6-ch usb servo controller

Attachment 3357

I don't think mach3 will interface with the thing you've bought, not without a lot of effort. I might be wrong though. You could just run it in the background and adjust it manually on the computer anyway?

Servo tester, still trying to trace the PCB. I think it'll work with the parallel port...

Ok disregard that, just had another look. It should be simple to get the servo tester connected.

:idea: Here's a step by step guide.

1. Remove the potentiometer, or just desolder the pin connected to R32.
2. Solder a wire to the pin of R32 that was connected to the potentiometer.
3. Connect the other end of that wire to the chosen output pin on the parallel port...say pin 14.
4. Solder a wire to the negative of the circuit board, e.g. pin labled '-' on connector JIN, and connect it to any ground pin on the parallel port.
5. Set PWM frequency in mach3 to something high, like 1000.
6. Under Config-->Spindle Pulleys set max speed to the max RPM of your motor.
7. Cross fingers...it should work as normal with the rpm show in mach3 corresponding correctly.

Hmm, before you do that measure the voltage between the pin of R32 that's not connected to the pot and ground whilst twiddling the potentiometer and see what the range is...


Ooh, is that a programming connector I spy on the PCB! Could be handy for something.

Disregard steps 1 and 2, that's not safe to do if the parallel port outputs over 5v. Measure the max voltage as I said in the previous post then just desolder the switch and solder the signal output wire from the parallel port to the PCB pin of the switch which was connected to R31. Then adjust the pot untill it gives the same reading for voltage with mach3 at 100% spindle speed as it did with the pot at 100%. Good idea to remove R32 whilst you adjust the voltage, then put it back when you're sure it's right - that guarantees not to break anything. Quite tricky soldering though!

hahaha!! yove been busy jonathan... hope you werent late up this morning

iv still got loads of drilling to do so i cant afford to pull my servo tester apart at the mo but iv orderd one exsactly the same for you to experiment with (if you agree) , PM me your address and ill send it over to you once it turns up here.

if you manage to solve the issue then let me know how you did it and we'll call it even :smile:

ps: dont worry about it if its more than you can be botherd with :)

just for a refrence iv mesured the voltage between both sides of R32 with the resistor still in place

0.24v both sides 0 speed
3v both sides flat out

thats with 5.57v coming in from the ESC battery eliminator

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Originally Posted by blackburn mark

iv orderd one exsactly the same for you to experiment with (if you agree) , PM me your address and ill send it over to you once it turns up here.

if you manage to solve the issue then let me know how you did it and we'll call it even :smile:

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That sounds like a good plan :) I've sent the PM. I'll work it all out properly and take some photos of what I do when I get it.

If that voltage is 3v max then we can use the existing potentiometer to scale the voltage from your parallel port to be the same.

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Originally Posted by chip

jonathan double check youve sent him the pm as ive some how ended up with it,your address etc..

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Sorry about that! I've sent it to the right person now :redface:

ok jonathan the pm got to me :) ill get it off to you as soon as it turns up to mine and we can all look forward to you smoking the thing :eek:

no pressure :lol:

Excuse me,
The PC parallel port outputs a binary signal, meaning it has two levels, off / on; or 0 / 1. The 0 is represented by a voltage less than 0.8v The 1 represented by a voltage greater than 2.4v.
Because the signal of interest is a PWM waveform, the voltmeter will be showing the average of the highs & lows of the signal. PWM means Pulse Width Modulation. By varying the proportion of ON time to OFF time in a given interval (20ms) the resulting effect is an analogue voltage. If the ESC wants a true analogue voltage input, a small value capacitor (1μF) between signal pin and ground will help.
If you have access to an oscilloscope this would all be really clear.
Thank you class for being attentive. Now, run along and play with your nice machines!

Oh! I just answered my own problem! Use the oscilloscope to monitor the output of the PWM line (from Mach3), and see how similar it is to the DCBLM drive module requirement!!

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Oh! I just answered my own problem! Use the oscilloscope to monitor the output of the PWM line (from Mach3), and see how similar it is to the DCBLM drive module requirement!!

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errrr.... let us know if you make any sense of the problem or if you use the capacitor, im asuming you already have an ESC and servo tester ?

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Originally Posted by templecorran

...signal of interest is a PWM waveform, the voltmeter will be showing the average of the highs & lows of the signal...If the ESC wants a true analogue voltage input, a small value capacitor (1μF) between signal pin and ground will help

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The ESCs we're using require a PMW signal with 20ms period. The range of the duty cycle used by the ESC is only roughly 5% to 10% - which means you don't get a very high resolution with mach3 connecting it directly. Only a handful of speeds in fact. Still probably sufficient in reality, but not ideal - hence why I'm still interested in investigating the servo tester adaptation. I agree a capacitor will certainly be required here, since the PWM signal is being fed into an ADC.

Just out of interest I connected my model car transmitter up to the parallel port yesterday in a similar fashion - it works fine which implies the servo tester conversion should also. I'm trying to control the parallel port in C now, so I can get the car driving itself around...

there are two things im dreading on this build....
hole sawing 25mm for the Y screw and drilling and tapping the bed plate

up to now iv used my diy spindle to do all my drilling and i was gagging to to be able to say id done the whole build with it and a tiny cowells 90 lathe:dance: however.... i think i may need to stop f***ing around and borrow a heafty drill

there is probably loads more stuff i should be flapping about but at this point i cant see past the drilling and tapping..... more drilling and tapping.... and!!!..... b***cks!!

Attachment 3369Attachment 3371Attachment 3370
for now i decided not to support the floating bearing on the Z screw, the housing that came with it seem such a waste of valuable space... ill make a low profile one if i have trouble with it whipping around

Servo tester arrived :)
I dismantled it straight away and sadly the PCB is different. I guess it's not surprising, hobbyking.com are allways changing their inventory.
We will still be able to do the same modification to both of them though - the voltages are similar.

I'll let you know as soon as I've done it - got a fair bit of work to do at the moment :(

dont be rushing it, i dont think either of us are in dire need of mach spindle control at the mo

have a crack at it in your own time jonathan, dont feel any pressure from me... im at least slack hand full of skinned knuckles away from fitting steppers never mind anything else

good luck when you do get to it :)

Ok then, it's just you sent it special delivery so I thought you were in a hurry!

'im at least slack hand full of skinned knuckles away'
You do think up some good expressions!

I'm going home for the weekend and I intend to get my router to the point of cutting stuff. I intended that last time I went home, but as is always the case with these things they take longer than expected and I ran out of metal.

Anyway, where did you get the long 1/8" cutter from for your little brushless motor? I'm warming to that idea for making PCBs...could use a really high feedrate with the cutter going at 60krpm (or more..) with one of the in-runner motors I've got.

Can't you get the existing spindle to drill nice grid of holes in the bed plate when it's all set up? That's what I'm intending to do.

i got one from germany (ebay) "Gravierstichel 3,175x115mm 60°x0,32mm VHM f. Pantograph"

then i found some cheeper ones in france (ebay) "1 fraise à graver(long taille) 3,175*60°0,25mm V-type"

iv been looking into sharpening them whilst still in the motor... it would need a jig making.... should get some good use out of them if they can be sharpend without to much hassle

the worry for me are the bearings on the nose, im convinced they will need cooling unless you splash out on ceramic ones and at those prices id still want to cool them, at 48000rpm they were very hot in under a minute, it might stay cool if you use one bearing but i think the runout will suffer, it needs some research

the other spindles are fine, i managed to hole-saw 25mm for my Y screw with the large one... had to take my time though, it keept tripping out my power supply

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could use a really high feedrate with the cutter going at 60krpm

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look on ebay for ceramic dental drill bearings(china), if i remember correctly about £25 for 5... iv not commited to those yet, my high speed spindle is way down my list at the mo but im looking forward to having a crack at making it work

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Can't you get the existing spindle to drill nice grid of holes in the bed plate when it's all set up? That's what I'm intending to do.

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im considering it........ im sh*t scared ill press go and end up with a road runner carved into my nice plate lol

ill need to stick a biro in my spindle and work on my confidence :)

im starting to wonder if i know what im doing with this thing
Attachment 3390
iv got a 12v 30A power supply in there for the spindle (couldnt fit the 45A in)
a 24v 15A for the steppers and a 5 axis china special :)
an old pentum4 system shoe horned in with a low profile cooler and a right angle riser for the graphics card, looks like it might get a bit warm in there and im right glad iv used sheilded cable for home switches and steppers

i used to throw this motherboard out of my way a couple of months ago :whistling: iv been holding it with two hands and tiptoing back n forth with it like its a new born baby.... i did test it before i comssioned it for a new life, in fact all the gear has been tested but im still going to squint my eyes first time i flick the on switch :eek:

can anyone tell me if ill be ok leap frogging the mains on all three power supplies and using a 220v 16A switch to turn the whole thing off (after the pc side of things has shut down of course)

At full rating and 100% efficient thats only 1 kw so at 50% efficiency 2KW at max, I expect most times it will draw a lot less.
Peter

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Originally Posted by ptjw7uk

2KW at max, I expect most times it will draw a lot less.
Peter

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cheers man, wiring isn't my strong point

I would put a separate fuse on each power supply. Whatever is standard for the computer (3A?), and probably similar for the power supplies. Bear in mind the surge current when you switch it on will be quite high. In my case switching on the stepper motors briefly dims the light in my workshop.


Oops, just realised you're talking about a switch not a fuse :redface: Nevermind I'll leave this here.

I'm liking where you've chosen to mount the electrics.

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dims the light in my workshop

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youve got heafty setup compared with mine

should i also run an earth to my frame, the power supplies are bolted to the frame but iv no idea how conductive the surface of anodised aluminium is ?

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Originally Posted by Jonathan

I'm liking where you've chosen to mount the electrics.

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The electrics look nice but really should be as far away from dust as possible.

There are people on the zone that have put the controls in a separate room with air from outside to cool the electrics.

Phil


Sent from my HTC Desire using Tapatalk

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as far away from dust as possible.

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ill not be cutting wood on this one (acetal/delrin) so i shoulden't suffer the unusual levels of dust that some of you lads have

I thought our drivers were the same? I've got 4 PM752 drivers on a 500VA (I think) toroidal transformer. Maybe it's the big capacitors that cause it...

I think the surface should be conductive enough for an earth. Whether it's a good idea or not I'm not sure. I'd be inclined to say yes.

Good point about the dust. Any fans in there are going to blow in a lot of dust. I found about a 5mm layer of wood dust (and some metal swarf!) in my computer when I cleaned it out on Friday. Probably should have made sure the case side didn't keep falling off, but still...

Edit: didn't see your last post in time :(

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I thought our drivers were the same?

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no, im on a chineese 5 axis TB6560, iv no idea if they will be enough, its a small machine but the gantry weighs almost as much as i do :) .... i think in some parts its over engineerd, i was trying to play it safe, the 20mm plate on the gantry sides are the week link.... i designed it with 200mm x 40mm extrusion but valuframe ran out of stock and couldn't find any

its amazing how much more the gantry sides flex in the Y axis compared with the X axis
ill stick some sort of buttress on them if its a problem

I thought the forum had something to stop double posting...oops. That's the problem with having a really slow internet connection.

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Originally Posted by blackburn mark

no, im on a chineese 5 axis TB6560...
its amazing how much more the gantry sides flex in the Y axis compared with the X axis
ill stick some sort of buttress on them if its a problem

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I'm not thinking today am I, you mentioned the driver only a couple of posts ago, sorry!

Plate is the worst possible cross section for bending in the Y direction. Maybe you could securely bolt some bigish aluminium angle to the plate to make it a bit stronger...ideally get it welded on.
All that aluminium profile must have cost a lot.

I intend to look at the servo controller on Wednesday, or this weekend at the latest.

i was thinking a 20mm arch bolted at 90 down the gantry sides, i need to work out where the torsion might be acting... im pretty sure it wont be a staight line top to bottom

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All that aluminium profile must have cost a lot

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Owch!! £100 meter, it did hurt spending that much but it is easy stuff to work with and its flat enough not to need machining

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I intend to look at the servo controller on Wednesday, or this weekend at the latest.

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have you got an ESC for that monster motor yet ?

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Originally Posted by blackburn mark

i was thinking a 20mm arch bolted at 90 down the gantry sides, i need to work out where the torsion might be acting... im pretty sure it wont be a staight line top to bottom

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Have you had a look at irving's spreadsheet on this? It's interesting comparing the different sections with it.

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Originally Posted by blackburn mark

Owch!! £100 meter, it did hurt spending that much but it is easy stuff to work with and its flat enough not to need machining

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Yikes, that's a ridiculous price when you compare it to the material cost.

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Originally Posted by blackburn mark

have you got an ESC for that monster motor yet ?

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Not quite. According to the website I need at least 100A and 48v ESC, which is going to cost a lot even from hobbyking! I think a lower current ESC should survive as I'll never need that much power. I'm thinking of replacing the mosfets on a really cheap 100A 24v ESC I have for some much higher voltage ones...that should do the trick for very little money.

Alternatively a friend of mine has randomly acquired a 5.5 KW 400v variable frequency motor inverter from a lift. I think it might be adaptable...

try "giant cod"
as cheap as ebay for some stuff

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irving's spreadsheet

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ill have to have a look for that

im not going to use mine at 1700w, i really cant see me needing that much, im not sure the 360w power supply im using will be enough... we'll have to see how it pans out, it would be interesting to see how it dose at 1700w
it has been a real work horse though and the windings dont get very hot

it'll be interesting watching your workshop lights when you fire up that 6000w job :)

Errrr..... has anyone had any experience with wiring home switches to an X axis thats driven with two steppers ?

in mach setup documentation it recomends putting a homing switch on each of the two x-axis drives to correct for lost steps and racking which im getting plenty of as im in the tuning stages of my setup... i only have enough inputs for 3 homing switches and an e-stop on my driver board

how do i conjure up a forth input ???????

A PCI parallel port card would get you plenty more inputs. There's probably a more elegant way to do it though...
Theoretically 3 inputs is enough if you put the switches in series/parallel etc with each X home switch on separate input - it's a matter of if mach3 can handle it. I'd like to know for my router...

I had a look at giant cod (what an odd sentance!). There's some interesting things but it's still a bit more expensive than www.hobbyking.com. Maybe I could use an E-bike controller on my motor.

Jonathan - Just noticed that your after a 100A 48v motor controller, I have got a few kicking around if you want one.

The ones I have take any voltage from 24 up to 48 and also can cope with anything up to 200A, fully programmable through 3 buttons on the front.

Let me know if you want some more information.

Oh, and I am sure the price will be right!

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A PCI parallel port card would get you plenty more inputs.

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i was worried someone would say that... my graphics card is blocking all my PCI slots... ill find a way.
im not going down the "series/parrallel" route with switches, homing and soft limits makes the most sense to my eyes

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Just noticed that your after a 100A 48v motor controller

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might be a winner :)

Mark i have not used a slaved axis but you can have all limits on one input, then maybe just the slaved axis on a separate input.

To anyone who wants more IO i use a PoKeys device http://www.poscope.com/product.php?pid=3

I have control panel with hardware buttons controlled through this device even does Speed and feed override via pots, MPG's etc

Phil