Can anyone please tell me what is the difference between this step/dir and cw/ccw on a stepper motor driver?because I dont know how to connect to the cw/ccw . please help
Can anyone please tell me what is the difference between this step/dir and cw/ccw on a stepper motor driver?because I dont know how to connect to the cw/ccw . please help
Hi Deslee
with step /dir
pulses to the step input makes the motor turn
the direction signal controls the direction (as expected)
with cw/ccw
pulses to the cw input turns the motor in one direction
pulses to the ccw makes it turn in the other direction
if you have the wrong control signals for a stepper driver
its possible to convert them
John
thanks john 100 I used the stp/dir bob to control cw/ccw driver ,nowander it did not work . so, do you have any kind of this schematic bob ,so I can make my own. hope to hear you so . thanks
Hi Deslee ,
since my last post ,
I've looked at your other posts and had a look at the AD5410 manual
the circuit below should help
the AND gates made from part of the 7400 and 7406 IC's
can provide more current than a 7408 AND gate to drive the opto isolators
the 150 ohm resistor limits the LED current to a similar level to the "MF"
inputs
the step signal is switched to the CW or CCW depending on the
logic level from the direction signal
(note the NAND gate used to send the inverted direction signal to
one half of the circuit)
John
Hi Deslee ,
I've just had a thought
you could use a 74241 octal buffer
only two of eight buffers are used
John
Hi John,
does this mean i have to use 3 74241 to link it to my stp/dir bob?
so,i can use 3 drivers.
because i just have some basic electronics knowledge .thanks
Where are your step/dir signals coming from?
I believe EMC can be configured to generate cw/ccw directly.
Hi Deslee,
yes you will need three 74241 IC's ( one for each axis)
the unused parts can not be used because each of the two enable pins
control 4 buffers
John
hello john
the circuit you give me is not working
I use it on kcam and mach3 no movement at all
any circuit I can try ? please let me know.
thanks.
stp/dir signals coming from parallel port.
what is EMC?
I've not used EMC
but I understand its a LINUX version of the
the Kcam and Mach3 type of software for windows
have you used Kcam or Mach 3 to control another stepper
motor driver before?
if not try the step and direction test circuit from Geckodrive :--
Support
look in application notes-
open the miscellaneous tab
then open step and direction tester
I've added led indicators to the 74241 circuit
the direction signal should switch between the two led's
the step signal should make one flash on or off
john
hi john
I did used kcam for the l297/l298 drivers
what do mean test circuit from geckodriver?
can you draw the led circuit for me?
thanks
Hi Deslee ,
it looks like you made your last post while I was re-sizing the picture of
the 74241 circuit with the two LED's added (one for CW and one for CCW)
the picture was too big when uploaded first time
the test circuit from Gacko was just incase you had problems
with the control of the printer port and the 74241 adaptor circuit
if you select in Kcam (or Mach 3) negative going pulses
one led should be on
the led will dim as you rapidly send pulses to turn the motor
for positive going pulses
the led will be off until , you send step pulses
the faster the pulses the brighter the led
you can test the 74241 circuit on its own ,with just a 5V supply connected
you should have one led on
connecting the direction input to 0V it should switch to the other led
connecting the step input to 0V will switch off the led
John
Hi john
sorry for the late reply,my computer just attack by virus ,cant get online.
Anyway, thank you so much for all the information you provided.
The circuit you gave is working great , is just my paraller port cable make
thing wrong .I bought another new one.
Its working great .Thank you , Thank you.
Hi Deslee ,
good to see its now working
did you add the LED's to see what its doing ?
the computer virus is a real pain
John
HI John
Yes I did add the LEDS to the board .When switch on ,
the led from the IC pin 7 stay on.
when move forward and backward ,the two LEDS became on and off.
Is good to have a LEDS on board ,made things more fun.
And john ,I have another question that need your help .
currently I am using the stepper driver board (L297-8)
this board I build was follow from the book
CNC ROBOTICS(Build Your Own Workshop Bot)
by GEOFF WILLIAMS
The book didnot mention a lot about the schematic,I was confuse ,
it seems that the board L-297 pin 15 VREF it just connect to somewhere else.I dont understand,because I read the pminmo.com website,the driver they build ,the pin 15 VREF it got an adjustable resistor.
so ,what I mean ,does its better have an adjustable resistor or if not? how it control the current to the motor.I also attach the schematic from the book.
thank you
Instead of using a potentiometer (adjustable resistor) to select the value for Vref, the schematic that you attached uses two resistors, labeled R5 and R6, as a fixed-value voltage divider circuit to get Vref.
The ratio of the resistance values shown on the schematic gives you a Vref of approximately 1/6 of the board's input voltage (1/6 of the "circuit voltage" applied to pin 1 of the JP1 power connector).
For more information about voltage dividers, see Voltage divider - Wikipedia, the free encyclopedia
Hi Deslee
the V ref for the circuit you have built will be 0.9V ( 5V x R5/{R5+R6} = 5 X {2200 /12200 })
this sets the current in the motor coils to 1.8A (Vref/ R1 = 0.9/0.5 )
what do you need to set the motor current to ??
circuits with a potentiometer to adjust the reference voltage makes it easy to set
the current for the motor ,an advantage when your experimenting
but with age potentiometers can become unreliable
with R1 and R2 being 0.5 ohm the maximum reference voltage is 1 Volt
as the total current limit for L298 IC is 4A ( 2A per coil)
if you change R5 from 2k2 to 4k7 and R6 from 10k to 18k
the reference voltage will be 5 x 4.7/22.7 = 1.03V , I = 1.03/.5 = 2.06A
John
Hi
Doorknob ,John
Both of you ,thank you so much .Now I know whats that all about.
I finally understand what it mean. thanks a lot.
deslee:banana:
Hi, this discusion is very interesting for me, I am trying to drive stepper drivers with CW/CWW inputs. I am still in research for BOB, but i want to test my drivers. Can I ask electronic gurus to have a look at the attached shematic - my drivers are not optoisolated. Will this work?
http://img249.imageshack.us/img249/7911/shemal.jpg
Uploaded with ImageShack.us
Hi
as the printerport can sink more current to 0v/gnd
than source current from the +5v supply
you may be better connecting the opto-isolator V+ terminals to +5v
from the computer usb port
and connecting the VF- terminal via the resistor to the printerport
John