AC motor control - PLCS.net

primrose · July 9th, 2006, 07:47 AM

Hi all,
I want to design a program to control three Ac motors at the same time. But the speed of each motor would not be the same. Since i m new to PLC programming, i need help. Is anyone out there can help me or give me some advice. Also feel free to give me basic ideas. I would be appreciate all.
Thanks..
Best regards..

PeterW · July 9th, 2006, 09:11 AM

what the motors for?

DOL's or VSD's?

what interaction between drives??

more info

Tom Jenkins · July 9th, 2006, 11:52 AM

This kind of question is very frustrating, because there is simply not enough information to provide a reasonable answer.

First, read the tutorial Learn PLCs at the top of the page. It will give you a basic idea about the way PLCs work.

To proceed you need to break the project into steps. You need to first of all write a description of the process, what is being controlled, what the basis of the control is, and what is going to dictate the sequence of operations and the machine.

Then you need to create an input/output list that identifies all of the sensors and switches read by the PLC inputs and all of the relays, drives, and devices controlled by the output.

Then you need to break the logic into steps, writing down the sequence for each control loop in plain language. You need to identify the adjustments to be made by the operator, like time delay ssettings etc. and how they will be entered. You need to identify the alarms that will be created, and the action to be taken by the PLC if they occur.

Then you can begin to write your logic. Don't try to do it all in your head in advance. Simply start writing the ladder logic using your description as a guide. Take it one step at a time. As you add new rungs you will probably need to go back and revise the logic already written as new ineractions and new ideas occur to you.

primrose · July 10th, 2006, 04:00 AM

what does DOL's or VSD's mean? I m not a programmer and i m just started to learn this programing. Sorry that i didn't give all the informations in detail. Anyway thank you so much for all the reply. I will try to break the project into steps and will try to work out on it.

Amr Hassan · July 10th, 2006, 04:12 AM

dol means direct on line
vsd variable speed drive
this terminolgy is related to motor not plc

July 9th, 2006, 07:47 AM	#1
primrose Member Join Date: Jan 2006 Location: singapore Posts: 7	AC motor control Hi all, I want to design a program to control three Ac motors at the same time. But the speed of each motor would not be the same. Since i m new to PLC programming, i need help. Is anyone out there can help me or give me some advice. Also feel free to give me basic ideas. I would be appreciate all. Thanks.. Best regards..

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July 9th, 2006, 09:11 AM	#2
PeterW Member Join Date: Jun 2006 Location: Edmonton Posts: 2,432	what the motors for? DOL's or VSD's? what interaction between drives?? more info

July 9th, 2006, 11:52 AM	#3
Tom Jenkins Member Join Date: Apr 2002 Location: Milwaukee, WI Posts: 4,971	This kind of question is very frustrating, because there is simply not enough information to provide a reasonable answer. First, read the tutorial Learn PLCs at the top of the page. It will give you a basic idea about the way PLCs work. To proceed you need to break the project into steps. You need to first of all write a description of the process, what is being controlled, what the basis of the control is, and what is going to dictate the sequence of operations and the machine. Then you need to create an input/output list that identifies all of the sensors and switches read by the PLC inputs and all of the relays, drives, and devices controlled by the output. Then you need to break the logic into steps, writing down the sequence for each control loop in plain language. You need to identify the adjustments to be made by the operator, like time delay ssettings etc. and how they will be entered. You need to identify the alarms that will be created, and the action to be taken by the PLC if they occur. Then you can begin to write your logic. Don't try to do it all in your head in advance. Simply start writing the ladder logic using your description as a guide. Take it one step at a time. As you add new rungs you will probably need to go back and revise the logic already written as new ineractions and new ideas occur to you.

July 10th, 2006, 04:00 AM	#4
primrose Member Join Date: Jan 2006 Location: singapore Posts: 7	what does DOL's or VSD's mean? I m not a programmer and i m just started to learn this programing. Sorry that i didn't give all the informations in detail. Anyway thank you so much for all the reply. I will try to break the project into steps and will try to work out on it.

July 10th, 2006, 04:12 AM	#5
Amr Hassan Member Join Date: May 2005 Posts: 340	dol means direct on line vsd variable speed drive this terminolgy is related to motor not plc

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