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Closing the Loop

We like car analogies so I'll start out this discussion with one.  What happens when you're going 45mph with the Cruise Control set and begin ascending up a hill?  Well, as you drive up that hill your car will require extra power(torque) or it will naturally begin to slow down.  As you start slowing down your car's cruise control feature recognizes you're no longer at the desired speed and automatically adjusts the engine's throttle to give your car the power to drive up that hill at your desired speed of 45mph.

As I see it, the factors that affect the ability to successfully maintain speed is load weight, friction, and pitch.  If any of the three change, the motor will require either more or less energy (Electrical Current) flowing to the motor.  Good thing for you, our ConveyLinx and EZ24 Family controllers have taken these factors into consideration and will place your roller into a type of "Cruise Control" while moving a load.  So how does "Closing the Loop" work?  

By clicking a box(ConveyLinx) or setting a dip switch(EZ24) you've effectively told our controllers to monitor the hall sensors inside the motor roller.  When the sensors inside the motor signal the controller that actual speed is not the desired speed the controller will either allow more energy or begin electronically braking the roller to reach the actual desired speed. One other important aspect to remember is when the motor is operating in Open Loop (default state), the motor speed setting you select represents the amount of energy going into the motor. So, 80% speed means the controller will allow 80% of the maximum allowed current into the motor based on the motor profile you selected.  When operating in closed loop, the speed setting represents the desired speed as a percentage of the maximum rated speed of that motor. The amount of current used will be left to the card to calculate on the fly in order to keep the angular velocity constant even when the load varies.

So, how will you or your customer benefit from closing the loop?

Have questions?  Want to know more about closing the loop? Send me some questions via email or phone (800-764-6356) and I'd be happy to answer them!  Or, you can  Find me on Google+ to discuss in more detail.