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usb step motor controller

usb step motor controller

Postby oddamann » Fri Mar 13, 2009 1:01 am

ordered the starterkit today - and found this packed for controlling the laser movement with a stepper motor.
http://pc-control.co.uk/osc/product_inf ... ucts_id=43

and then I discover that it comes with a DLL interface for programming in visual basic
http://www.pc-control.co.uk/vb_stepperbee.htm

The packet can control 2 stepper motors - 6 output swithes
and have 6 high/low inputs

Can David-Laserscanner communicate with this DLL interface ?
maybe via the new virtual COM ......

I'm not a programmer

oeSoeraa
oddamann
 
Posts: 15
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Re: usb step motor controller

Postby jonb2000 » Tue May 05, 2009 5:05 pm

All

Interested in contollers that will control the Laser's oscillatory circular motion on a step motor from A to B which are 160 degrees apart.
Will appreciate if you can help me identify the unit that meets this requirement.

Thanks,

jonb2000
jonb2000
 
Posts: 14
Joined: Mon Mar 16, 2009 3:35 pm

Re: usb step motor controller

Postby jonb2000 » Wed May 06, 2009 4:25 pm

Hi oeSoerra,
The product you have mentioned is a stepper motor controller, which won’t give you the results that you are looking for.
Here is an excerpt from Wikipedia regarding stepper operation.
Stepper motors operate differently from normal DC motors, which rotate when voltage is applied to their terminals. Stepper motors, on the other hand, effectively have multiple "toothed" electromagnets arranged around a central gear-shaped piece of iron. The electromagnets are energized by an external control circuit, such as a micro controller. To make the motor shaft turn, first one electromagnet is given power, which makes the gear's teeth magnetically attracted to the electromagnet's teeth. When the gear's teeth are thus aligned to the first electromagnet, they are slightly offset from the next electromagnet. So when the next electromagnet is turned on and the first is turned off, the gear rotates slightly to align with the next one, and from there the process is repeated. Each of those slight rotations is called a "step," with an integral(complete number) number of steps making a full rotation. In that way, the motor can be turned by a precise angle.
Stepper motors are constant power devices. As motor speed increases, torque decreases. The torque curve may be extended by using current limiting drivers and increasing the driving voltage.

Steppers exhibit more vibration than other motor types, as the discrete step tends to snap the rotor from one position to another. This vibration can become very bad at some speeds and can cause the motor to lose torque. The effect can be mitigated(lessen) by accelerating quickly through the problem speed range, physically damping the system, or using a micro-stepping driver. Motors with a greater number of phases also exhibit smoother operation than those with fewer phases.
Steppers are good for general purpose industrial applications, but the cogging behavior (a.k.a. “step”) isn’t well suited to continuous motion applications, such as an optical scanner.

But if you have already used a Stepper motor, please let me know your experience with a Stepper also.

Regarding your earlier question :
"Can David-Laserscanner communicate with this DLL interface ?
maybe via the new virtual COM ......"
I don't think it will be a problem because the two communication channels ( PC to Laser & Camera to PC) are completely independent of each other.
I hope this helps.

Thanks,

jonb2000
jonb2000
 
Posts: 14
Joined: Mon Mar 16, 2009 3:35 pm


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