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stepper rotate 180 deg.
- Thread starter AMPdeck
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falleafd
New Member
To drive a stepping from 0 to 180 deg, you need a program, not a circuit.
If you need a stepping driver, you may try with some driver chip: ULN 2003 or 2803 for 2 motors. It's the simplest way to drive a stepping. If you wanna use a H bridge, try with L298 and L297 (L297 is the higher level control chip, and enable you to drive a stepping with PWM).
If you need a stepping driver, you may try with some driver chip: ULN 2003 or 2803 for 2 motors. It's the simplest way to drive a stepping. If you wanna use a H bridge, try with L298 and L297 (L297 is the higher level control chip, and enable you to drive a stepping with PWM).
ivancho
New Member
Your circuit will need the 3 stages.
:arrow: The POWER stage: This is a chip like a H-Bridge that connects to your stepper motor and has the ability to handle the voltage and current requirements for the stepper. Ex: L298
:arrow: The DRIVER stage: This is a chip that will be in charge of driving the POWER chip. The DRIVER chip will need to generate the right secuence to stepping the motor. It will drive the motor by accepting "CLOCK" inputs and converting them to steps. Ex: L297
:arrow: The COUNTER stage: This will be the clock for your DRIVER chip, it will generate the necesary clock pulses to tell the DRIVER to go 180 degrees and back. Ex: "4017 + 555 (monostable)"
It would not be fun for you to show you the circuit, but you can start with the above information. :wink:
Some thing to think about....
:?: how many steps are needed for a 180 rotation.?
:?: How many pulses needed to achive the steps?
:?: How can we use the "direction" pin on the driver chip.?
Good Luck
Ivancho
:arrow: The POWER stage: This is a chip like a H-Bridge that connects to your stepper motor and has the ability to handle the voltage and current requirements for the stepper. Ex: L298
:arrow: The DRIVER stage: This is a chip that will be in charge of driving the POWER chip. The DRIVER chip will need to generate the right secuence to stepping the motor. It will drive the motor by accepting "CLOCK" inputs and converting them to steps. Ex: L297
:arrow: The COUNTER stage: This will be the clock for your DRIVER chip, it will generate the necesary clock pulses to tell the DRIVER to go 180 degrees and back. Ex: "4017 + 555 (monostable)"
It would not be fun for you to show you the circuit, but you can start with the above information. :wink:
Some thing to think about....
:?: how many steps are needed for a 180 rotation.?
:?: How many pulses needed to achive the steps?
:?: How can we use the "direction" pin on the driver chip.?
Good Luck
Ivancho
falleafd
New Member
[PDF] www.st.com/stonline/books/pdf/docs/1773.pdf
Try this link, the datasheet of L298. I think you can easily connect L298 to MC, and it easy enough to write a simple program for stepping. You don't have to use L297 if you don't want to simplize your program even it's simple enough as with L298.
However, you need to take care of short circuit protection, apply to both L298 and L293 (B/D)...
goodluck.
Try this link, the datasheet of L298. I think you can easily connect L298 to MC, and it easy enough to write a simple program for stepping. You don't have to use L297 if you don't want to simplize your program even it's simple enough as with L298.
However, you need to take care of short circuit protection, apply to both L298 and L293 (B/D)...
goodluck.
falleafd
New Member
The datasheet of L298 and L297 show clearly how to connect to a stepper. I did as in the datasheet. But I added a short circuit protection to it. And the short circuit protection is also supported on www.st.com. I don't remember the direct link.
But it's as:
a zener 4148 is connected from the inputs of L298 to signal pins of MC, and a capacitor is also connected in parallel with it. It's about 100pF. And a Resistor 10K should be connected from the inputs of L298 to the outputs of L298. You do it with all inputs and outputs.
But it's as:
a zener 4148 is connected from the inputs of L298 to signal pins of MC, and a capacitor is also connected in parallel with it. It's about 100pF. And a Resistor 10K should be connected from the inputs of L298 to the outputs of L298. You do it with all inputs and outputs.
falleafd
New Member
Well, the circuit should like this:
...........x-----||---x
...........|.............|
|O|-----x---|<|----x---- |X| this is the input of L298
Don't care bout the .... , I have to add .... because if I don't, it cannot view exactly. ---- is the wire, and x is connected. |X| is the input pin of L298 and |O| is the output of your MC. You need only 1 pin, but in stead of connect it directly, you connect like this. And from the input of L298 to output of L298, you add a 10K resistor.
If you got a email, I'll send you the test circuit, I used to test L298 with its all characters, such as: short circuit, feedback voltage via sense pins, 4A driver, ... and especially, we should note that if we use the normal diode for the H brigde, we cannot drive the motor upto 5KHz period of PWM, but if we use fast diode, it works good. And PWM is usually used at that frequency.
...........x-----||---x
...........|.............|
|O|-----x---|<|----x---- |X| this is the input of L298
Don't care bout the .... , I have to add .... because if I don't, it cannot view exactly. ---- is the wire, and x is connected. |X| is the input pin of L298 and |O| is the output of your MC. You need only 1 pin, but in stead of connect it directly, you connect like this. And from the input of L298 to output of L298, you add a 10K resistor.
If you got a email, I'll send you the test circuit, I used to test L298 with its all characters, such as: short circuit, feedback voltage via sense pins, 4A driver, ... and especially, we should note that if we use the normal diode for the H brigde, we cannot drive the motor upto 5KHz period of PWM, but if we use fast diode, it works good. And PWM is usually used at that frequency.
mail...
offcourse
[email protected]
a orcad fiel would be fine or something in paint..
TKS (or Walter)
offcourse
[email protected]
a orcad fiel would be fine or something in paint..
TKS (or Walter)
ivancho
New Member
AMPdeck: With those parts it sounds like you are in the right way to make it happen, I would be interested to see what you done for kicks.AMPdeck said:
Have in mind that it would have been easier to use a L293 + L298 combo (or similar chips) with a microcontroller, for practical purposes. But for learning purposes on how things work, your way is the best 8)
Ivancho
ivancho
New Member
The ULN2003 it is just an H-bridge drive type of thing.... well it is actually high voltage, high current darlington arrays. As you probably know to move a stepper motor you need to send a sequence of signals, which will energize the coils of the stepper accordingly. So the ULN2003 is not just enough. His project is to use discrete IC type of thing.falleafd said:
A microcontroller could actually generate those siganls needed but it takes too much time of the controller to generate them.... instead a specific chip can be used to generate that sequence for you, like the case of the L297, so that you only need one line to control the stepper instead of 4. Not to mention that software part will be reduced as well.
By using those chips he mention somehow he comes with the right secuence without the need of programming, and that is an art.
Ivancho
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