What should be the output of the DIR and STEP pins of the UMI 7764 for normal stepper motor operation when it is run from MAX?

[enigmata]

I get a pulse in the STEP pin, but the DIR pin shows no signal on my oscilloscope.

[risheeb]

Hi enigmata,

If your stepper axis is configured for Step & Direction mode, the DIR signal should be high when the axis is moving in one direction and low when it is moving in the other direction.  The STEP signal will output a single pulse for each step movement.

I hope this helps.


Rishee B.
Applications Engineer
National Instruments

[enigmata]

When u say the DIR signal has to go high for 1 direction of rotation, and Low for other, do you mean a constant amplitude signal, eg. 5V high for all time when rotation aoccurs? Coz when i checked it out with an oscilloscope, i only got a pulse for starting of motion, like a trigger pulse... That is wat created this doubt. Which of these is right?

[risheeb]

Hi enigmata,

If you command the axis to move in one direction, then the Direction signal should stay at a constant level for the entirety of the move.  The level will be low or high, depending on the direction.

What happens when you configure the Stepper Output Mode to Step & Direction?  You can set this in MAX in the Stepper Settings tab of the Axis Configuration category.  When you have this mode configured, the Step signal becomes the Clockwise signal and the Direction signal becomes the Counter-Clockwise signal.  When you command a move, you should see a series of pulses on either line, depending on the direction.


Rishee B.
Applications Engineer
National Instruments

[bacobaco]

Hi,

I'm in trouble with the DIR output. I use PXI 7350 and the 7764 board.

My motor never changes direction and the signal DIR stays at 0 volts even I create motor cycle through MAX (or through a Labview example).

Test I've already done:

- I try to change the drivers output to "open collector" instead of totem(DIR stay at 5 volts even I use MAX motor cycles)

- I try differents AXIS with my 7350

- I control my board controler and I can reverse the motor if I apply directly 5 volts on the DIRECTION PIN of my controller.

I'm gonna be nervous...

thanks for help !

-damien

[risheeb]

Hi Damien,

I do have a couple suggestions that may help.

First, the UMI-7764 does require that a +5V power supply is connected to the Power Input Terminals.  Can you confirm that a power supply has been connected?  You can find the location of these terminals on page 4 of the UMI-7764 User Manual.

Also, can you tell me what happens when you switch the output to the Clockwise/Counter-Clockwise configuration, as I suggested earlier in this thread?  Thanks.


Rishee B.
Applications Engineer
National Instruments

[AnalogKid2DigitalMan]

Problem resolved in this thread (cabling issue)

http://forums.ni.com/ni/board/message?board.id=240&thread.id=6278