[nick mulder]

beginner here:violin::

if I have 1000ppr encoders can I simply put a CMOS or similar digital divider to halve or quarter its output ?

If I were dividing the pulses counts by 4 and the servo were to 'wiggle' backwards and forwards by one step (one 1000 step) 4 times for whatever reason would I get a false reading ? ? - or would the absolute encoder system/programming sort this out ? ?

cheers all ,

Nick

[ejkoeze]

Hello Nick,

It's better to use the built in step multiplier. This multiplies each step pulse from your parallel port by a certain factor and effectively reduces encoder resolution.
Keep in mind the UHU processor is able to read more than 100000 encoder pulses per second. The exact speed escapes me but I recall something like 135000 pulses per sec
1000cpr in quadrature equals 4000 pulses per rev. This means that if your motor is running at 25 rev/second you'll be closing in on the limits of your system. This equals 1500rpm so use motors that have max 1500rpm or be prepared to have lesser performance. It's generally not a good idea to hook your encoders to your spindel and srive the motor at a higher speed via a transmission since the play in the transmission may cause jitter or even oscillations and may put a great stress on the output stage.


Uli correct me if I'm wrong.

Erik Jan

[ulihuber]

Nick,

you should use the step multiplier function as described by Erik Jan.

To be honest, I did not have the environment to test the ultimative step rate. Theoretically it is 266 kHz if the controller runs without RS232 communications.

Give it a try !

Regards
Uli

[nick mulder]

righto ! thanks guys i'll give it a go as is - I got these servos free and thought I may try to make use of them as testers for my UHU project before i got some real grunters especially for my application - I could always fill in every other groove in the encoder disk (tedious and destructive work) but am not sure if its a hall effect or IR type ...

[nick mulder]

quick query that I hope is useful (as I hate to bog down forums with off-topic weight) ... buuut, I got some surplus current sensing resistors outlined here:

http://www.cnczone.com/forums/showth...387#post136387

would these find any place on a UHU system ?? (bearing in mind a PCB alteration) -


btw, speaking about bogged down forums I spent an hour and a half last night going through this thread and copying and pasting all the techinical info I thought would be relevant to me making the board minus all the chat and dead-end queries (not to say they weren't relevant to begin with its just they ended up that way more or less)

It's an undistilled and smallish collection of these copy'n'pastes (eg, diode info, starting up process, heatsink this, heatsink that etc...) - if anyone from the 'lets get all this info together' section a few pages back wants me to forward it to post on a wiki or wotnot I'd be glad too ...

[FPV_GTp]

Servo controller developed in Germany.

Since I have seen a couple of very interesting threads here that I have read with great pleasure and from which I have learned a great deal I thought I’d pass trough some things I have learned elsewhere. On the cncecke.de (German CNC forum) there have been developments that should not be made available to just German reading enthousiasts.

Many of you will have seen the pages made by some Japanese guy that made a simple Servo controller complete with schematic for the driver board and source code for it’s Atmel processor. This project seemed to have a lot of potential and a couple of guys went to work on it. The result is a controller that is able to work with DC Motors with ~200 to 500 CPR encoders and with up to about 3000 RPM.
The controller board can be adapted to drive DC servo’s with power in excess is 1 kW!!!
It has a serial port which can be used to alter PID parameters, debug and finetune the controller. There is a dedicated (DOS) program that can be used for this, that has a little graph showing the position of the servo in realtime (for fine tuning and reducing overshoot). It is controlled with normal Step/Dir signals just like nearly every other Stepper driver. It has a current limiter.

Safety measure include the following.
Daisy chaining controllers to ensure shutdown of all controllers in case a single one has an error. Emergency stop can also be wired to this.
Current limiter
Adjustable position error shutdown (if for some reason the position error exceeds a preset value the controller is shut down.
If the controller hangs the output stage is shut down so no irretic behaviour can occur.

About the amount of power this thing can supply. Yesterday there was a post of a guy that had 1.6kW servo’s attached and while trying to determine the correct PID parameters it started to oscilate. Afterwards his son asked him why the house had vibrated to stangely…. Another has replaced his industrial Haidenhain controllers with these.

The project is not completely open source since the author of the software for the controller keeps the code to himself. However controllers can be bought from him at cost price and the entire project is called beerware. Repay him his costs (2 euro per controller (programmed) and postage and send him a beer or something else usefull (couple of milling bits, centre drills, or whatever) and he’s completely content.
I have built my first controller and I’m impressed.

This can take home cnc’ing to a whole new level. Imaging the amount of power and accuracy this will give your machine not to mention the increase in speed.
At about 40 Euro (~$50) (depending on where you get them) in parts this cannot be called expensive.

Erik Jan
Layout and schematic
Controller software (DOS) and manual (also in English)

Edit: Corrected link.

hi ejkoeze


reading the vast amount of information on this site on all topics

this one caught my eye on the stepper/servo motor drivers

would love to use this setup for my first electronic CNC Plasma Table

will follow this section very carefully as it has some serious potential for my project

guys im new to all this stuff so be easy on me if i ask what may seem a stupid questions to you but to me its a learning curve

cheers

[nick mulder]

Hiya -

working through the parts list at Mouser from the 'UHU 12_21 parts.pdf'

couple of parts not turning up in the catalog:

- the P6KE12AC transient suppresor ... lists the P6KE12A as a substitute, which is non-stocked and I would have to order 4000 of them ...

Digikey have them but I dont know to go for out of three options:
TVS UNI-DIR 12V 600W DO-15 , DIODE TVS 12V 600W UNI-DIR or
TVS 12 VOLT 600 WATT UNI-DIR - any other substitute at mouser tho ?


Also not in the catalog are any mention of 2w 1.8k resistors ... can I simply run two in series to make it up or would a 2w 1.5k or perhaps 2k I can get here in NZ be ok ?

no mention also of the MUR120 diodes but I found they have the UF4004 and HER105 types so that is ok ...

also the list mentions I need 5 'Insularor Transtor' I dread seeing how many hits I would get putting in insulating transistor if that is what this is ??

any help appreciated .

cheers all,
Nick

[ulihuber]

Nick,

you are fine with 1.5k 2W.This is not at all critical.
UF4004 is perfect, as well as HER105.

No idea what these 'Insularor Transtor' are ...
Maybe the little plastik washers you need to mount the transistors to prevent the screw from touching the metal part of the transistor ?
Anyways, you need to mount the transistors isolated from the heat sink.

BTW the 0.01 resistors will not work. Just to small resistance.

@all: Please don't use the linkk of the first posting of Erik Jan, it is outdated. Go to the website www.uhu-servo.de where you'll find the actual information about the UHU controllers.

Uli

[Manjeet]

Hello all,

I have made the PCBs for the UHU Servo controller. The good quality PCB with 75 micron copper layer thickness and with solder mask will cost 8 USD any quantity + shipping charges any one interested please do mail me.

Manjeet

[nick mulder]

is the P6KE12CA an ok replacement for the P6KE12AC ?

when I search for the P6KE12AC in google there is no hits but it suggests that I may instead want to search for the CA - just a guess ? Mouser has plenty of the CA voltage suppressors but no AC types which are listed in the latest parts lists I can find.

Thanks for the reply Uli re. the 2w resistor.

I'll tell ya, that having only just found this thread it is easy to find links all over the place to parts lists, schematics and PCB designs - many of which all have the same name along the lines of 'UHU.pdf', 'parts.pdf', 'UHU.jpg' which turn out to be different files and often have only subtle differences eg. the diodes have changed in the list...

It would help the late-comers if people put the date the file was made in the file name (as some have) - this would avoid confusion about the evolution of versions of the board - it would be excellent if the links to your site were somehow added to that post ..

ah well tho - its still all good !

I'm about to make my first order from mouser and newark, just need the info on the P6KE12AC/P6KE12A/P6KE12CA volt supp part ...

cheers mate + else's involved -

Nick

[ulihuber]

Nick,

it IS the P6KE12CA ... :-))

Any other type without the 'C' works as well. But the C-Types are bidirectional and do not need to be placed in a certain direction.

Uli

[nick mulder]

Nick,

it IS the P6KE12CA ... :-))

Any other type without the 'C' works as well. But the C-Types are bidirectional and do not need to be placed in a certain direction.

Uli

hot dang! (flame2) - cheers for that ... there was a typo in the parts list

[vroemm]

I have made the PCBs for the UHU Servo controller. The good quality PCB with 75 micron copper layer thickness and with solder mask will cost 8 USD any quantity + shipping charges any one interested please do mail me.

Finally someone who has added his info to the UHU wiki !
A good way to use the UHU wiki.
Thanks :-))
http://gsst.wikispaces.com/UHUget

[turmite]

Hello all,

I have made the PCBs for the UHU Servo controller. The good quality PCB with 75 micron copper layer thickness and with solder mask will cost 8 USD any quantity + shipping charges any one interested please do mail me.

Manjeet

PM sent.

Mike

[coleong]

Hello Manjeet,

How can i sent you the money US$8.00 and what is the postage plus packing to Malaysia?

Do you have a picture of the pcb?

Best regards,
coleong

[Manjeet]

Hello everybody there,

Will anyone translate the UHU servo parts list in english. if it already there tell me the webpage address.

Cheers ....Manjeet

[Manjeet]

Hi Coleong,

for PCB contact me through Personal mail. for my Email ID. please see http://gsst.wikispaces.com/UHUget

Manjeet

[dfv]

does anybody control a spindle with the uhu board? I have a PROXXON BFW 40/E (40V,250W) and i would like to put it a two channel encoder to control direction and speed with mach2 software.

[ulihuber]

dfv,

I do not have a DC controlled spindle, but I see no reason why it shouldn't work.
A guy from Finnland wanted to do so, but I have no feedback yet.

Uli

[nick mulder]

Anyone else in New Zealand here going ahead with a UHU board ?

I'm investigating getting some PCB's made here - the cost per board halves if I get 9 of them made compared to the 3 initial ones I need ... I was going to etch my own but the costs were almost comparable to get them etched professionally - yet I'm still left drilling the holes ... ah well gotta do *some* of the work (;

On another note, I'm very keen to hear about and see pics of the other 1000 or so chips that have been made - I have serials 965 to 974 and have just got all the components together for two boards one with the irf540's and the other with the more powerful 260's

Any interesting stories, hints, interesting bits made with these boards ?

I personally am going to set them to work moving 16mm film cameras around