Driving stepper motors

[Robert Coe]

Working on a project that will use a stepper motor, that will need to run at a preset rpm on power up.

Am concidering using a NE555 in astable mode to provide step pulses to an  Easy Driver stepper motor driver board.

My concern is that I’ve heard that steeper motors may be driven into resonance rather than rotating if driven without “ramping the step pulses” to the desired speed. (9200 to 55200 steps/minute)

I prefer to avoid problems rather than run into them.

Does any one have first hand knowledge or experience with this scenario?

Any and all info greatly appreciated.

Bob

 

“The only truely stupid question is the one that wasn’t asked.”

 

[Ashutosh Bhatt]

Stepper motor can hv 4 coils or 2 coils. To rotate them pulses must be given in sequence. U can get the idea from tutorials on stepper motor.

[Robert Coe]

That is why I’m using the easy driver stepper motor driver.

Please read the question fully when replying.

[Ashutosh Bhatt]

i dont know what is Easy Driver stepper motor driver board. how it works how it functions. u can build simple stepper motor driver using IC555 and johnson counter and ULN2003A current driver chip that gives pulses in sequences to stepper motor to rotate it. the speed of motor can be changed by changing frequency of applied pulses from IC555.  you can not apply more pulses then max RPM of your motor.

like if max RPM of motor is 6000 then you can not give more than 6000/60 = 100 pulses per second

[Robert Coe]

Thanks for your input.  The easy driver uses a stepper driver chip that has all the logic and drivers built in.

All it requires is input for step size, direction and a step pulse.

 

I’ve solved the ramping of step pulses by adding an RC circuit and a transistor between the timming resistors R1 of the astable 555 and Vcc, as the capacitor charges the transistor slowly turns on effectively ramping the frequency of the step pulses.

I bread boarded the circuit and it work perfectly. The stepper motor slowly ramped speed, to the preset speed, set by R1, of the astable circuit without locking into resonsnce.

 

[Ashutosh Bhatt]

thanks for your answer and also for posting the solution.

i am especially thanking you because everybody just post the problems nobody posts the solution.

one more thing. pls post the photo-snap of easy stepper motor driver board so that other can get idea of it

[Robert Coe]

Here is a link to info about the Easy Driver (Stepper motor driver board). You will be able to find links to vendors there too.      schmalzhaus.com/EasyDriver/index.html

 

[Ashutosh Bhatt]

thanks

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