Lab OBSOLETE - Simple Motor Control

 

Objective:

The PLC will be used to control a DC motor, and a simple encoder will be used to detect position.

 

Equipment:

PC with micrologix programming software

PLC trainer boards

Wires

LEDS

Motors with gear head

Encoder disk

560 ohm resistor

1K resistor

1 uF capacitor

photo emitter/detector pair (H21A1)

 

Pre-Lab:

1. Develop a state diagram for a program to turn the motor shaft 3 times if button A is pushed, or 6 times if button B is pushed.

2. Develop ladder logic for the motor controller.

 

System Description:

The motor will be driven with 12V, switched by an output relay in the PLC. This will cause rotation at approximately 100rpm. A simple encoder will be made by using a clear disk with blacked-out areas. The disk will rotate with the shaft of the motor. An optical sensor will be used to detect the blacked-out areas. The result will be input pulses that go into the PLC. By counting the pulses we can tell how many times the shaft has rotated. The figure below shows the photodetector circuit.

 

 

The light beam will be broken with encoders that have the general pattern given below.

 

 

Procedure:

 

1. Connect the motor, PLC, and any required wiring.

2. Load and test the program for correctness.

 

Minimum Required Submission:

 

1. Prelab design work

2. Wiring diagram

3. Program, with comments and test results

 

 

 

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