E6.7.2.4
Elevator control with PLC
System
Programmable Logic Controllers (PLCs) are used extensively in many manufacturing processes and control applications being readily programmed and reprogrammed when variations in the controlled process are required. This elevator illustrates the principles of PLC interfacing & control based on a real-life and easily identified application, therefore providing excellent interest for students. Starting with simple program sequences to control elevator speed, direction and floor arrival/departure, the student can progress to advanced floor request handling and continuous (analogue) control with acceleration profiling and compensation for varying car loads. The internal motor speed controller has both logic and analogue interfaces such that a basic PLC with minimal digital I/O can be used to implement control. More sophisticated control may be developed if analogue I/O is available. The load-cell and motor position feedback signals are available to develop programs for continuous control. The load-cell indicates elevator car loading and a set of weights simulates varying numbers of car occupants. The position feedback signal allows for the development possibility of advanced control of the elevator car motion.
Function
- Fully working model of an elevator with 4 floors
- Floor sensing and visual indication of travel
- Motorised elevator car door
- Brake to hold car at desired floor
- Up/down call button at each floor
- Front panel manual switch for testing
- Integral motor servo controller
- Interfaces with most PLC types
- Pre-wired or "wire your own" Mitsubishi, Allen Bradley & Siemens PLCs available (purchased separately) or use your own
- Analogue inputs & outputs available
- Switchable faults
- Elevator units can be "banked" together, as per numerous elevators in a larger hotel
Topics
- Logic fundamentals
- Basics of PLC programming
- Developing ladder logic programmes
- Basic sequencer control
- Advanced sequence control
