Programmable logic controllers basics
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13-1 Dr. D. J. Jackson Lecture 14-1 Electrical & Computer Engineering Programmable Logic Controllers Programming the Unitronics V1040 PLC: Getting Started, Basic Ladder Logic, and HMI Operation Dr. D. J. Jackson Lecture 14-2 Electrical & Computer Engineering VisiLogic Overview • VisiLogic is the software tool you use to create control projects for Vision controllers. – Used to write, debug, and download the PLC control and HMI applications into the controller. – The PLC application is your control, or automation application • You write the PLC application using the Ladder Editor – The HMI application configures the operating panel's function • You use the HMI Editor to create the Displays that are shown on the controller's screen.
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The Presentation covering the basics of programmable logic controllers.
Transcript of Programmable logic controllers basics
13-1
Dr. D. J. Jackson Lecture 14-1Electrical & Computer Engineering
Programmable Logic Controllers
Programming the UnitronicsV1040 PLC: Getting Started, Basic Ladder Logic, and HMI Operation
Dr. D. J. Jackson Lecture 14-2Electrical & Computer Engineering
VisiLogic Overview
• VisiLogic is the software tool you use to create control projects for Vision controllers.– Used to write, debug, and download the PLC
control and HMI applications into the controller.– The PLC application is your control, or automation
application• You write the PLC application using the Ladder Editor
– The HMI application configures the operating panel's function• You use the HMI Editor to create the Displays that are
shown on the controller's screen.
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Dr. D. J. Jackson Lecture 14-3Electrical & Computer Engineering
HMI Displays
• Displays tell your operators what to do– Provides status information about the system– Links to ladder logic being solved by the PLC
• You can have your operators enter data, and have the display instruct the operator what to do in case of a system problem or alarm
• A Display can contain both text and images– Text and images can be both fixed and/or variable
Dr. D. J. Jackson Lecture 14-4Electrical & Computer Engineering
HMI Variables
• Variables are inserted into a Display to:– Show run-time values as integers– Represent run-time values with either text,
images, or bar graphs– Show text messages that vary according to
runtime conditions– Enable an operator to enter data using the Vision's
alphanumeric keypad
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Dr. D. J. Jackson Lecture 14-5Electrical & Computer Engineering
VisiLogic Editors
• You use different editors to create your control project:– Hardware Configuration– Ladder– HMI Display– Variable
• Hardware Configuration• Define PLC type, communication, I/O modules, etc.• Similar concept to Allen Bradley hardware configuration
• Ladder Editor• Used to create the Ladder diagram that comprises your control
application• Ladder diagrams are composed of contacts, coils, and function
block elements arranged in nets
Dr. D. J. Jackson Lecture 14-6Electrical & Computer Engineering
VisiLogic Software Layout
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Dr. D. J. Jackson Lecture 14-7Electrical & Computer Engineering
Hardware Configuration
• Select V1040 PLC type
Dr. D. J. Jackson Lecture 14-8Electrical & Computer Engineering
Hardware Configuration• Use “Connection ->
Communication & OS” to define connection between PC and PLC.
• PC Port may vary
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Dr. D. J. Jackson Lecture 14-9Electrical & Computer Engineering
Ladder Editor
• In a Ladder diagram, the contacts represent input conditions– They lead power from the left Ladder rail to the right rail– This is why the first element in a net must always touch the
left rail• Coils represent output instructions. In order for
output coils to be activated, the logical state of the contacts must allow the power to flow through the net to the coil– This is why the elements in a net must be connected– Each net must contain only one rung
Dr. D. J. Jackson Lecture 14-10Electrical & Computer Engineering
Ladder Editor
• Use the Ladder Editor to:– Place and connect Ladder Elements– Apply Compare, Math, Logic, Clock, Store, and
Vector functions– Insert Function Blocks (FBs) into your program– Build program Modules and Subroutines, and use
internal Subroutine Jumps and Labels– Place Comments on Ladder nets
• Ladder elements and functions may be dragged and dropped between nets
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Dr. D. J. Jackson Lecture 14-11Electrical & Computer Engineering
Basic Ladder Logic Example
Dr. D. J. Jackson Lecture 14-12Electrical & Computer Engineering
Operand Types
• We will use the following operand types in our initial examples– MB – Memory Bit– MI – Memory Integer (16-bit)– ML – Memory Long (32-bit)– T – Timer (32-bit)– C – Counter (16-bit)
• Other operand types will be introduced as needed
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Dr. D. J. Jackson Lecture 14-13Electrical & Computer Engineering
Basic Ladder Elements - Contacts• Direct Contact -- a normally open (NO)
contact• Inverted Contact -- a normally closed (NC)
contact• Positive Transition Contact (Rise)
– A one shot pulse when the referenced bit changes from 0->1
• Negative Transition Contact (Fall)– A one shot pulse when the referenced bit
changes from 1->0
Dr. D. J. Jackson Lecture 14-14Electrical & Computer Engineering
Basic Ladder Elements - Coils• Direct Coil -- turns ON when
the preceding net conditions are ON
• Inverted Coil -- turns OFF when the preceding net conditions are ON
• Set Coil -- turns a set coil ON(latches), when preceding net conditions are ON
• Reset Coil -- turns a set coil OFF (unlatches), when preceding net conditions are ON
• Toggle Coil -- changes its state when it is activated
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Dr. D. J. Jackson Lecture 14-15Electrical & Computer Engineering
Simple Ladder Logic Program
Dr. D. J. Jackson Lecture 14-16Electrical & Computer Engineering
HMI Editor
• Insert shapes, buttons and images onto the display and associate them with specific elements (operands) from the ladder logic program
