[Konstantin]

I got it.
I believe that the schematic of the chopper board has incorrect labels for the X2-1 and X2-2 connector, they're swapped.
X2-1 should be positive and X2-2 should be negative.

The first time I hooked the PSU my led didnt lid, so I thought "Oh well , I always get confused with the leds" and I resolder it so it lid, but the problem was another.

Correct me if I am wrong.



Konstantin.

[Konstantin]

Well I have hooked the PSU correctly to the chopper.
The motors spin allright, aparently.
There have been some jerking in one of the motors, maybe TurboCNC settings might need adjustment. Max speed 1000 for now, latency 33.

I am using 3n3 on the chopper, IRF9540 get HOT. Not all the same as hot.
The zenners not very hot, just one of them. The resistors do not get as hot as with the PSU wrongly connected. I wonder if the chopper board suffered any damage because I ran it with the wrong polarity?

The discrete unipolar drivers are not even warm.

One thing still puzzles me. My motors are 5.2v and my PSU is 25. The chopper will limit the current amount accordingly to the resistors I used and the cap, right?
But what about the voltage? The voltage on my motors will be 25, correct? Is that allright for the motors? They were a bit warm that's it.

Konstantin.

[tachus42]

I'll have to check the supply connections later. It's very unlikely any damage was done by the reverse polarity. Sounds like some heatsinks are needed on the 9540's try a small shaped piece of aluminum even a bit from a can should work ok.

A simplification is to think of the chopper supplying small pulses of voltage so the average voltage is correct. But really steppers are current operated devices. So what we need to do is forget about the voltage rating and just supply the correct current.

Good to hear it's working in any case.

[berin]

You should check out the SLA7024M/SLA7026 "1.5amps/3amps constant" uni polar stepper drivers! they have built in choppers which is controled by a pentiometer, and they operate by by 4 ttl inputs for each step. they run upto 36v/ X amps.
http://smba.kpc.ac.kr/admin/bbs/data/Drive/SLA7024.pdf
This i what I'm going to base my controller on, and I have a friend working on building a stepping controller out of a 16f877 which with ANY luck will include a step buffer so there will be no problems with windows jerkyness in running stepping motors straight from the par-port.
a few other features he's working on will be a hardware step limate so the controller its self will not let the machine advance past the limate switches +/-. an other feature he's hopping to add will be a hardware level max pulse rate with ramping. which would also be adjustable because this pic chip has software editable eeprom. there are more things I could write but I'll wait for an other time, I also give it about 2 months tops for a beta to be out. This will be a very compact modular design. for now dual 16f84's with the public asm step/dir driver kit from the turbocnc page are my step/dir to phase controllers.

[pminmo]

Berin,
While the 7026 is a nice looking part, at over $10 apiece and no stock anyplace I'm not sure it's good to base anyting on just yet. What benefit is there over the L297/298 or a3977 and running bipolar?

Phil

[pminmo]

Konstatin,
On the interface board, LED2 needs to be removed and jumpered for Estop to work correctly. I updated the Document for it.

Phil

[Ito-Brazil]

This Allegro 7026 simply doesn´t exist heare in BRAZIL, i´ve searched. If someone have other idea, let me know too.

[berin]

well for starters very simple basic design circuit wise, onboard variable chopper controller. If you cant find them to purchase they are in all kinds of devices. Mainly BIG!! printers and photo copyers and photo machines period! They are in almost every old dotmatrix printer. and I'm not talking about the little okidata. I'm talking about the big two foot wide printers. There is an electronics salvage place near me which I raid every now and then. next time I go threw if I pick up a bounch of these chopper phase driver chips I'll post that I have some available.

[pminmo]

4 Axis interface board now available: http://webpages.charter.net/pminmo/cncelectronics.htm

Phil

[Ito-Brazil]

Sorry, Master, I didn´t understood, it´s a 3axis and a 1axis, or a 4axis ? and where can i get a 1axis and a LPT-PCB-adapter ?

Hey, thanks a lot! Because you i will make my own CNC !!!! Maybe a new future!

[Ito-Brazil]

OH, sorry again, i got it NOW !!! I´m a bad listener !!! hahhaha

[pminmo]

Ito,
There are many different boards, and lots of ways you can configure.

Phil

[pminmo]

Ito here are two pictures to help explain.
Picture 1 is the three axis INTERFACE board. On the left side is a db25 connector that via a cable hooks to a pc's parallel port. The three 10pin cables on the left go to 3 single axis stepper driver boards as pictured in the 2nd picture. (the top one is non funtional, just convienient for picture) The driver boards pictured are based on Allegro's a3977 chip to driver bipolar steppers rated up to 35V and 2.5 amps. If you want to drive one of the steppers as unipolar, then you can use one of the 5804 or discrete unipolar designs. The driver boards in this example can all three be the same or two the same and one different or all three different. i.e. mix to your needs.
The 3 axis board of Tachus42's is one board not four as shown in the picture. It has three axis of unipolar drivers plus the connection to the computer parallel port.

Phil

[Grom1]

Sorry for my English. But Allegro chip has 2.5 A current limit.All steper drivers have a current limit 3 A.But stepper motors have 6 A current.What feed it motor?

[Grom1]

Sorry. What does feed it motor?

[Cossie]

Hi tachus

I got a few newbie questions, can i use IRL530 insted of IRLZ44 FETs as they are really expensive here in Denmark and can i use ECM265M-E1.0A steppers with the 3 Channel Discrete Unipolar Board and howto wire them.

ECM265M-E1.0A Datasheet -> http://www.ec-motion.de/pdl/ECM265M_d.pdf

Regards
Michael - Denmark.

[Ito-Brazil]

Hey, Master Phil:
THANKS A LOT! Now i´m close to understand the electronics of a CNC.
AND NOW I BELIEVE THAT I CAN DO IT !!!!
hey, NEWBIES, unite ! Let´s learn together!
Thanks again PHIL. PHIL IS OUR KING !!!!!

[Ito-Brazil]

I have the same problem: my motors have this specs:
Current: 3.1A ;
Volt: 2.6 V

May I use the 5804 based PCB ?
Sorry the "abuse"...

[tachus42]

Cossie
IRL530s will be ok for your motors. You could use a 12 volt supply and 6.8 ohm current limiting resistors as a starting point. The winding connections are shown on the datasheet. Connect the Wires with a white stripe together for each phase to make the common.

[Cossie]

Cossie
IRL530s will be ok for your motors. You could use a 12 volt supply and 6.8 ohm current limiting resistors as a starting point. The winding connections are shown on the datasheet. Connect the Wires with a white stripe together for each phase to make the common.

Thanks tachus for you help..

btw, are those steppers any good for an CNC ??

Regards
Michael - Denmark.