Newbie- cnc step/dir. cw/ccw

[deslee]

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

[john_100]

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

[deslee]

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

[john_100]

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

[john_100]

Hi Deslee ,

I've just had a thought

you could use a 74241 octal buffer

only two of eight buffers are used

John

[deslee]

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

[Andre' B]

Where are your step/dir signals coming from?
I believe EMC can be configured to generate cw/ccw directly.

[john_100]

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

[deslee]

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?

[john_100]

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

[deslee]

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

[john_100]

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