Transcript Programming Logic Controllers

Programming Logic
Controllers
Overview - Chapter 1
PLC Use
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Machine control
Process control
Motion control
Batch control
Diagnostic
Other
Usually Multiple applications
History and Development
• 1960’s
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“Five hours to find it, five minutes to fix it”
History
• Richard Morley – Modicon
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First PLC
ladder logic programming
• Odo Josef Struger
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Allen-Bradley
History and Development
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http://en.wikipedia.org/wiki/Programmable_logic_controller
http://en.wikibooks.org/wiki/Introductory_PLC_Programming
http://www.isa.org/Content/ContentGroups/News/2006/February24/His
tory_of_the_PLC.htm
http://www.barn.org/FILES/historyofplc.html
http://www.control.lth.se/media/Education/DoctorateProgram/2012/Hi
storyOfControl/Vanessa_Alfred_report.pdf
http://www.plcs.net/chapters/history2.htm
Block Diagram
Block Diagram
Block Diagram
Central Processing Unit
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http://en.wikipedia.org/wiki/Central_processing_unit
A central processing unit (CPU) is the hardware that carries out the
instructions of a computer program by performing the basic arithmetical,
logical, and input/output operations of the system.
Memory Devices
• RAM
• ROM
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ROM
Programmable ROM (PROM)
Erasable programmable ROM (EPROM or UVEPROM)
Electrically Erasable ROM (EEPROM)
• Static RAM
• Dynamic RAM
Address Decoder Unit
• Address to circuit
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Binary number to path
Binary
• http://www.jodyculkin.com/category/comics-2/countingbinary
Decimal pattern
Binary numbers
0
0
1
1
2
10
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11
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100
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101
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110
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111
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1000
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1001
Transisters and Gates
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http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/trangate.html
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http://www.cs.bu.edu/~best/courses/modules/Transistors2Gates/
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http://www.cs.bu.edu/~best/courses/cs101/F95/lectures/FromGatesToAdder.html
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http://www.electronics-tutorials.ws/logic/logic_10.html
Peripheral Chips
• Buffers
• Data conversion
• Networking
• Voice
• Voice Recognition
• more
Discrete Input Modules
• Discrete means enumerable, countable, not continuous but
distinct
• Digital not analog
• Real numbers are not discreet
• Between 1.0 and 2.0 we have 1.50.
• Always a number between x and y
• Integers are discrete. No number falls between 1 and 2
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On or Off
1 or 0
True or False
Closed or Open
Discrete Output Modules
• Set to on/off
• Set to true/false
• Set to 1/0
Analog Input/Output Devices
• Analog is a continuous signal (wave)
• Set to varying voltage levels
• Inputs converted to digital via analog to
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digital converter logic
Digital to analog conversion occurs for
outputs
PLC Power Supply
• Battery backup
• Capacacitor allows battery exchange
Allen-Bradley
Programmable Logic Controllers
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PICO
MicroLogix
Small Logix
SLC 500 Series
• LAN and WAN capabilities
• PLC-5
• May have thousands of I/0 ports