PCI 6024E used in stepper motor control

[Himanshu]

Dear Sir,
For controlling the Stepper motor the only thing that is to be controlled is the pulses given to the stepper motor.The next thing is changing the pulses to another set of stator poles.My idea is that I will generate finite controlled pulses using the D I/O and output it to the stepper motor via current and voltage amplifier.If I get proper ckt. that increases the current capacity and amplifies the volatge then I think we can control the stepper motor speed the only problem that remains is that the pulses have to be sent to alternate poles. I am unable to think of any system which alternates the pulses to another set of poles. Please feel free to give your advice as I am not very experienced. I am very sure you will a
dd your valuable suggestions and comments.
Thanking you
Himanshu Mishra

[Filipe A.]

Hello;

I'm not sure if I got the issue correctly, but by my understanding you need to send digital output pulses to one set of poles, and then do the same operation for another set of poles. If the number of digital lines needed for pole is up to 4, you can use the first 4 lines to output data to the first set of poles and the last 4 lines to do the same operation on the other set.

If each set of poles requires more than 4 lines, you will need 2 DAQ boards to accomplish that.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments

[RoyA]

Filipe,

He would not be sending one set of pulses and then another. He needs to send two (I think) simultaneous pulse trains to two sets of alternating poles. The duration and frequency of the pulse train controls speed while the amount that the two pulse trains are out of phase controls the direction. I do not remember the exact relationship, maybe someone in your motion control group could shed some light.

[Brent_R]

The 6024E has 8 static DIO lines and 2 counter IO lines. Since the DIO lines are only software controlled, you probably will not be able to switch the lines fast enough to control a stepper motor, which can require 10kHz or more depending on the desired velocity. If you have an amplifier that accepts STEP/DIR signals, you could use one digital IO line to control the "DIR" line and one counter to output a pulse train to control the "STEP" line. The speed of the motor could be varied by changing the pulse rate from the counter and the direction controlled by switching the DIO line.

This would give you very basic contol of the motor. You could control 2 motors with the 6024E, since there are 2 counters available, however I would not expect very smooth results.


Regards,

Brent Runnels
Applications Engineer
National Instruments

[RoyA]

Thanks, Brent. That is the info I couldn't quite remember. I personaly think he would be better off purchasing the amplifier that accepts STEP/DIR signals. He will probably spend MUCH more time and money trying to develope his own circuit.

[RoyA]

Himanshu,

I believe that Filipe was incorrect. You would not be sending one set of pulses and then another. You need to send two (I think) simultaneous pulse trains to the two sets of alternating poles. The duration and frequency of the pulse train controls speed while the amount that the two pulse trains are out of phase controls the direction. I do not remember the exact relationship, maybe someone out there with more stepper experience could give you the details. Most stepper motor companies have driver circuits for their motors that will accept digital control.