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Day 3Programming a
ProgrammableController
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Objectives Describe the available options for programming a PLC.
Explain what online is in comparison to offline.
List the advantages of software programming with a
personal computer over a hand-held programming
terminal.
Explain the differences when interfacing a notebook
personal computer to a PLC.
Discuss open or soft PLC programming.
Provide an overview of the IEC 1131-3 standard.
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PLC Run Mode (1 of 2)
The PLC can do nothing without someone developing a
program and loading it into the PLC processors memory.
Once the program has been loaded into PLC memory, the
processor is put into run mode.
While in run mode, the processor is solving the ladder
program.
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PLC Run Mode (2 of 2)
While in run mode, the processor reads field device input
signals and stores them in memory.
There is one memory location for each input screw
terminals ON or OFF state.
Field device status information is stored in the input status
table.
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PLC Programming
The oldest programming method is the hand-held
programmer.
Most popular programming method is IBM-compatible
personal computer using either DOS or Windows software.
Higher-end PLCs can only be programmed using software.
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Allen-Bradley SLC 500Programming Options
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Allen-Bradley SLC 500
Hand-held Terminal (HHT)
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Hand-held Programmer andSLC 500 Modular Processors
Hand-held are used only on fixed SLC 500, 5/01, and 5/02 processors.
5/03, 5/04, and 5/05 modular processors allow software programmingonly.
MicroLogix 1000 PLC has own hand-held programmer.
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Smart Hand-held ProgrammingTerminal Advantages
Compact size
Easy to use and learn, no software required
Low cost; cheaper than notebook computer
Easy to transport a program to the field
Easy to transfer PLC program to HHT for editing or
troubleshooting
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Smart Hand-held Programming TerminalDisadvantages
Holds one program at a time
Newer more complex processors do not support
Limited capability to display ladder rungs
Documentation not displayed
Many keystrokes needed to program or edit ladder program
Dead battery means program lost
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Software ProgrammingUsing PC Advantages Newer software Windows-based
View or monitor multiple ladder rungs
Documentation displayed
Easy to scroll through rungs for troubleshooting
Programs stored on computers hard drive
Programs transferred to floppy or CD-ROM
Easy editing and programming, drag and drop, cut andpaste, etc.
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Software ProgrammingDisadvantages
Maintenance personnel must learn Windows programming software.
Notebook computers are expensive.
Interface cards are expensive.
Personal computers are not designed for factory use.
There are frequent software upgrades.
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Allen Bradley 1747-PIC Interface
1747-PIC communication box used to communicate from aPCs serial port to a SLC 500 family data highway 485 PLC
Connects to any PC with a serial port
Communicates with fixed SLC 500, and 5/01, 5/02, and
5/03 modular processors
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AB 1747-PIC InterfaceConverter Interface
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Connecting a GE RS-422/RS-485to a RS-232 to a PC (1 of 2)
Image courtesy of GE Fanuc Automation
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Connecting a GE RS-422/RS-485to a RS-232 to a PC (2 of 2)
Easy connection between personal computer and Series 90-30 or 90-70
PLC
Connects to computer serial port
Connects up to 50 feet away
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Desktop or IndustrialComputer Interface to PLC
Allen Bradley 1784-KTX interface card
PC ISA expansion slot card
Connects to data highway plus or data highway 485 processors
Set up RSLinx software drivers to communicate
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Allen-Bradleys1784-KTX Interface Card
Image courtesy of Allen-Bradley, a Rockwell Automation business
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1784-KTX Card andNetwork Interface
Easy network connectivity between personal computer and up to 64
data highway plus PLC 5 or SLC 5/04 processors (nodes) on DH+
network
Up to 32 data highway-485 SLC 500 family processors on network
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Node Addresses
Each device on the network will require a unique identifiercalled a node or station address.
Data highway plus network will support up to 64 nodes,
using octal addresses.
Data highway-485 network will support up to 32 nodes,
using decimal addresses.
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Communicating to
Multiple SLC 500s
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Notebook PC Interface to PLC
Direct serial connection
Hardware interface device such as 1747-PIC
PCMCIA card
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PCMCIA Interface Card
Notebook PCs do not have expansion slots for installationof KTX card.
PCMCIA card is a credit-card sized plug-in interface card.
Allen-Bradleys PCMCIA card is called the 1784 PCMK card.
1784 PCMK card serves as an interface between a PLC and
a PC used as a programming terminal.
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1784 PCMK Card Installation
Interface between notebook PC and either DH+ or DH-485
Interface PLC 5 or SLC 500 family processors
Insert card into notebook computer PCMCIA slot
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PCMK Card Insertion
into a PCs PCMCIA Slot
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Interface Cable Attachment
to PCMK Card (1 of 2)
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Interface Cable Attachmentto PCMK Card (2 of 2)
One cable to communicate to SLC 500,
DH-485 processors
One cable to communicate to SLC 5/04, DH+processor
Same DH+ cable will communicate to PLC 5 processors
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Interface Cable fromPCMK Card to PLC Processors
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Industrial Computers
Notebook and desktop personal computers were notdesigned for continuous use in the manufacturing
environment.
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Industrial Computers
Are Designed to Withstand:
Dirt
Shock
Vibration
High temperatures
Wash downs
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Industrial Computer Features
Shock-mounted hard drives
Air filters with air intake fans
Hazardous environment rating
NEMA 12, 4, and 4X ratings
Integrated mouse on front panel
Air-conditioned enclosure not required
Modular for easy repair
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Two Styles of Industrial Computers
Panel-mount
Computer and monitor built into one integrated unit
Rack-mount
Computer either separate component mounted in standard
19-inch rack or embedded inside enclosure
Separate monitor or touchscreen display
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Rockwell Automations RAC 6181
Computer Connections
Image courtesy of Allen-Bradley, a Rockwell Automation business
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Connecting Industrial Mouse and Keyboardto the RAC 6181
Image courtesy of Allen-Bradley, a Rockwell Automation business
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IEC 1131-3Programming Standard
Defines a consistent set of programming languages for PLCs:
Ladder diagram
Function block diagram
Instruction list
Structured text
Sequential function block
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Sequential Function Chart (2 of 2)
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Sequential Function
Chart OR Logic
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Sequential Function ChartIllustrating a Simultaneous Branch