Learning Outcome 1: Design a PLC programme to solve an industrial process problem for a given application
Analyse alternative strategies for using other types of programmable control devices in industrial applications
Learning Outcome 2: Demonstrate the use of PLC programming and simulation software in a given application
Learning Outcome 3: Review the different types of programmable control devices available
Learning Outcome 4: Examine an industrial application to determine the required characteristics of a control device
Demonstrate the use of test and debug software to correct PLC program faults
Learning Outcome 5: Explore the practical uses of PLC advanced functions
PLC programming & Other programmable devices
Review the problems faced by using alternative devices in an industrial environment
Critically evaluate a PLC programme used to solve an industrial application problem
Critically evaluate the selection of an alternative programmable device in a given application
Introduction
Programmable Logic Controllers (PLCs) were invented by the American Richard (‘Dick') Morley in 1969, to be used in the manufacture of cars. Prior to that date production lines had been controlled by a mass of hard-wired relays. Using programmable devices in their place meant that changes in production could be implemented much faster without the need to rewire control circuits.
The aim of this unit is to further develop students' skills in the use of PLCs and their specific applications within engineering and manufacturing. Among the topics included in this unit are device interface methods, PLC signal processing and communications with other devices, PLC programming methodology and alternative programmable control devices.
On successful completion of this unit students will be able to research the design, selection, and use of PLCs as part of a larger system, programme a PLC to solve an industrial process problem for a given application and illustrate the alternative strategies for using other available types of programmable control devices.
Task 1
Explain the difference between a microcontroller and a microprocessor.
Determine the required characteristics of a control device to be used to control automation process in a mining environment.
Produce a technical report for the sales engineers that compares current PLC control methods with alternative microcontroller-based methods such as PIC, Arduino, Raspberry Pi etc. Your comparison should include
• the ease of programming,
• specialist knowledge and training required.
• consider purchase, operational and maintenance costs
• range of availability and types and ease of interface with process plant and equipment.
Task 2
• Write a logic to generate a pulse output at Q0.0 using pulse timer blocks consider the time pulse to be1 second.
• Modify your ladder logic and use two pulse timer blocks, write a logic to generate a continues pulse output at Q0.0 consider the time pulse to be1 second.
• You must identify all inputs and outputs and list them in a table which clearly gives any labels, description and addresses used. Also include any memory locations, timers etc that will be used.
• You must include screenshots of your full solutions showing how you tested them under monitoring.
• Give a detailed explanation of the operation of each program. This must be a description of what happens on each rung.
Task 3
An apprentice in your company is designing a control system for a sorting station in which products are going to be sorted according to sizes and material. The apprentice has decided to make this system using a small an Arduino and you have advised him to use a Siemens PLC instead
• Review the problems the apprentice will face when he tries to use embedded systems.
• Reviewproblems of using other alternative devices in a manufacturing industrial environment.
• Critically evaluate the selection of an alternative programmable device in an industrial application.
Task 4
As an Automation Engineer, you have been assigned the task of designing a ladder logic utilising a counter on a shop entrance. The counter is there to give an indication of how many people are in the shop and be able to compare the number to a set shop capacity. Your aim is to demonstrate application of advanced functions of an S7 1200 siemens PLC. Taking an example of a counter with PV 50write, test, and debug the PLC ladder program using a suitable software package utilising the following comparators.
• Equal (==) (check if the number is equal to 25)
• Not Equal (<>) (Check if the number is not equal to 25)
• Greater or equal (>=) (Check if the number is greater than or equal to 25)
• Less or Equal (<=) (check if its less than or equal to 25)
• Greater than (>) (Check if its greater than 25)
• Less than (<) (check if its less than 25)
• In range(use the range20 to 30)
• Out of range (check outside the range 20 to 30)