drive a stepper motor by SLA7062

[Jo_Jo]

sla7062

hello everyone.
did anybody use the SLA7062 to drive and control the stepper motor?
i cant understand something
1\what does the SYNC use for?
2\the rated voltage of my motor is 6.6V,but VBB is just from 10V to 44V, what should i do? connect them directly?
3\are the RsA and the RsB same?
4\if i use ATMEGA64 to control it, should i use some appropriate pull-up resistors?

do anybody have sucessful experience?

**broken link removed**

 

[VVV]

sla7062 circuit

I have not used this particular IC, but similar others.

the SYNC synchronizes the switching of the two phases, in order to reduce noise when the motor is stopped (but holding). Otherwise, it should be LOW. See page 7 of the datasheet.
So you drive this signal high when the motor is stopped, if the noise bothers you. But once the motor starts running, you should drive SYNC low.

This chip uses current mode control, so the motor's voltage rating is not important. The chip will adjust the CURRENT through the motor and that will produce a certain voltage across the motor. It will be different from the 6.6 (lower), especially in microstepping mode.
Having said that, you select RsA and RsB appropriately in order to limit the maximum current to the motor's rated current. RsA=RsB=Vref/Imax.
Make sure Vref is 0.1V~2V. 0.5~1V should work fine.

So Vbb must be 10~44V. You just use a voltage in that range, say 12V and let the circuit take care of the motor current/ voltage.
Use +5V for Vdd.

And yes, RsA and RsB are equal, since the currents through the motor's phases should be equal.

I do not know ATMEGA64, but I do not think you need any pullups, since the logic side of this chip is powered at 5V and the logic inputs are TTL compatible.

 

[Jo_Jo]

sla 7062

Thank you VVV, but i still cant understand the question 2, about voltage of VBB, is it equal to the input voltage of my motor? and the rated voltage of my motor is 6.6V, but VBB should be from 10 to 44V.
Thank you

Jo_Jo

 

[IanP]

sla7062 board

There are two types of driving loads: voltage or current.
If, for argument sake, you apply to your motor 6.6V the motor will draw say, 0.5A.
So if, in current control mode, you apply 0.5A to your motor, what will be the voltage accross it? The answer is 6.6V..
This chip, as VVV mentioned, uses current control, and the current is set by RsA and RsB .. read current rating of your motor from it's data sheet and select RsA and RsB accordingly.
You can now supply the circuit of >10Vdc and dont worry about voltage rating of your motor ..
Regards,
IanP

 

[Jo_Jo]

sla7062 project step mortor

Thank you Ianp, i think i have understanded meaning of you and VVV. It is due to the current control mode. So, thank you.
And i have another qustion, if i use that chip, all the input voltage is logic, high or low, and no PWM input, right?

 

[IanP]

sla7062 -3axis

The PWM blocks ar inside the SLA chip.
Controls (inputs) are of 0 to 3.3 (or up to 5V, depending on Vdd) logic levels .. L or H only ..
Regards,
IanP

 

[Jo_Jo]

stepper motor driver allegro sla7062

Thank you Ianp, i think i can go on my design, ^_^

Added after 22 minutes:

i have another question, in the figure of page 11, what does the P-GND and the S-GND mean,

 

[IanP]

sla7062 motor driver

S-GND stands for "signal ground" and this is related to all TTL/CMOS I/Os, and P-GND stands for "power ground".
These two should be "almost" separated, preferably connected only at one point, as suggested by the drawing ..
Regards,
IanP

 

[Jo_Jo]

driver sla7062

Thank you Ianp, i got it, ^_^

Added after 1 hours 32 minutes:

i have another question,
in the figure of page 11, i think Q1 is wrong,should it be reverse. i think the direction is from S to G,not from G to S.

 

[IanP]

reducing noise on a sla7062

It is a p-channel mosfet, where source is connected to Vdd and drain to Vref (pin7).
To disable, you will have to drive the gate to 0V (L),; this will open p-channel mosfet and pull Vref (pin7) to Vdd ..
Regards,
IanP

 

[Jo_Jo]

reset cct for sla7062

Thank you IanP, you mean if i give 0V to gate, this mosfet will be open, and the Vref is equal to Vdd. but i should make sure that the voltage of Vref is 0.1V~2V.So i must give 5V to the gate,and ensure that R1 is effective,right?

im a newbie on control of stepper motor, sorry for the easy qustions, and really, really thank you for your replies,

 

[IanP]

reset schematic for sla7062

That is correct, for normal operation the gate voltage has to be at Vdd level, and then R1 + the variable resistor set the Vref voltage at pin 7..
Regards,
IanP

 

[Jo_Jo]

stepper motor controller circuit sla

Thank you very much, IanP, I appreciate your helping in time

Jo_Jo

 

[Jo_Jo]

sla7062 project

hi all, im back.
i have new question.i want to select a p-channel mosfet,but what i found is that they all have high voltage,and high current.finally,i choose the 2N6845. did you here that before?could you give me some advices. thankyou

 

[IanP]

sla7062m with pic

This p-channel mosfet is used as a switch, so you can put there any p-channel mosfet ..
You can also consider any pnp transistor, such as commonly used BC107, 337, 557 etc etc ..
Just connect 4.7-10kΩ resitor between its base and the µC pin, and it will do the same job as that p-ch mosfet ..
Regards,
IanP

 

[Jo_Jo]

sla7062m base circuit

thank you very much, IanP

 

[edison]

sla7062 motor driver

Jo_Jo

I had some similar questions about the Allegro SLA7062, but I've come up with a circuit & PC board for the SLA7062 that seems to work fine. I'm using p-channel mosfet BS250. See the attached schematic or more details at: www.techkits.com

-ED

 

[Jo_Jo]

sla7062 step motor control schematics

hi edison.
seems a late reply.
I have finished that project. now samples are made by workers. I control the SLA7062 directly by mcu, and you? but seems that your surrounding circuit is so complex.

Added after 44 seconds:

edison, the website doesn't work.

 

[davegrennan]

unipolar stepper motor driver 3.3 mosfet

Hi Guys,

First post here, looks like a really great board.

I am building a board using the SLA7062M and found the above very helpful. I have some questions still unanswered and hope someone can help.

I have a unipolar stepper motor rated at .95A. Using Rs = Vref/Imax it's quite difficult to find the right balance between selecting sense resistors and a potential divider to get Vref and the sense resistors to limit the current to .95A. I suspect that by limiting the current to a value below .95A would be fine. Would that assumption be correct?

Would it be ok to tie a TTL output of my MCU to the RESET pin in the 7062 direct and then send the 7062 to sleep by putting that pin high? (or must I use a transistor to take VDD to RESET and then use my TTL output to open the transistor?

Please forgive the dumb questions of a keen hobbyist.

Best Regards,

Dave Grennan
Dublin-Ireland.

 

[nio_4]

assembly code motor drive

hey,

I'm currently using the SLA7062M unipolar stepper motor driver/translator . I' would like to ask as about that, how can i control this chip with microcontroler-PIC.
I use the PIC16F876 and i've clock frequency 10MHz for timing. So, the instruction word is tc= 0,4 μsec. More over, i saw the picture with name "logic input timing" in datashet of SLA7062M on page 4.

could you write a simple code in assembly code which is possible to move stepper motor???

John,

Added after 36 seconds:


As well as, i have write the following in assembly code but, it isn't work:


;**************** arxh programmatos ***********************

ORG H'20' ;kanoume Reset thn mnhmh tou PIC
;o kwdikas ksekinaei apo thn dieu8unsh mnhmhs 0

;**************** diamorfwsh PIC *********************

BCF STATUS,RP1
BSF STATUS,RP0
clrf TRISC ;pou elegxei ton driver-translator
BCF STATUS,RP0
movlw b'11000000' ;energopoioume tis diakopes
movwf INTCON ;PANDA meta apo ka8e diamorgosh-teleutaia

;**************** kwdikas *********************


;**************** dinoume 12 bhmata 90 moires + kateu8unsh *********************

step

movlw .8 ;

movwf PORTC ;dinoume
NOP ;kateu8ynsh
NOP
NOP
movlw .40 ;me palmo 2 μsec

movwf PORTC ;sunexizoume na dinoume
NOP
NOP
NOP ;kateu8ynsh ---- kai bhma-step
movlw .32 ;gia ---- 2 μsec

movwf PORTC ;dinoume mono
NOP ;bhma-step 4 μsec gia na
CALL delay4 ;sumplhrwsoume thn 8etikh hmiperiodo (6μsec)


clrf PORTC ;kanoume
NOP ;thn arnitikh hmiperiodo
CALL delay4 ;4μsec
movlw .8 ;kai sta 2 teleutaia
movwf PORTC ;dinoume kateu8unsh
NOP
GOTO step ;gia 2 μsec


delay4
NOP
NOP
NOP ;xronoka8usterhsh
NOP ;2,4 μsec
return ;tc=0,4 μsec*6=2,4 μsec


eg

END