Rockwell international Allen-Bradley VIM 2803 User manual

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Important User Solid-state equipment has operational characteristics
Information differing from those of electromechanical equipment.
“Application Considerations for Solid-State Controls”
(Publication SGI-1.1) describes some important differences
be.tween solid-state equipment and hard wired
electromechanical devices. Because of this difference, and
also because of the wide variety of uses for solid-state
equipment, all persons responsible for applying this
equipment must satisfy themselves that each intended
application of this equipment is acceptable.
In no event will Allen-Bradley Company be responsible or
liable for indirect or consequential damages resulting from
the use or application of this equipment.
The examples and diagrams in this manual are included
solely for illustrative purposes. Because of the many
variables and requirements associated with any particular
installation, Allen-Bradley Company cannot assume
responsibility or liability for actual use based on the
examples and diagrams.
No patent liability is assumed by Allen-Bradley Company
with respect to use of information, circuits, equipment, or -
software described in this manual.
Reproduction of the contents of this manual, in whole or in
part, without written permission of the Allen-Bradley
Company is prohibited.
6 1987 Allen-Bradley Company
$50.00

Table
of Contents
Chapter Title Page
1 Using this manual
Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . _
What This Manual Contains . . . . . . . . . . . . . . . . . . _. .
Audience . ..___._._._........._................
Vocabulary . . . . . . . . .._.....................__._
Warnings and Cautions . . . . . . . . . . __. _. . . _. . . . . . .
Related Publications . __. . . . . . . __. __. _. . __. . . . . . .
Revision Information __. . . . . . . . . . . . . ___. . . _. . . . .
l-l
l-l
l-2
l-2
l-5
l-6
l-6
2 Introduction to the Vision Input Module (VIM)
Chapter Objectives .............................
What isthe Vision Input Module? ................
Functional Features ............................
HardwareFeatures .............................
Vision Input Module Hardware Description . . _____
The Vision Input Module (Cat.#2803-VIMl) . . __
Light Pen (Cat.#2801-N7) ....................
Camera (Cat.#2801-YB) ......................
Camera Cables ..............................
VIM Power Supply (Cat.#2801-Pl) .............
Video Monitor (Cat.#2801 -N6) ...............
Video Monitor Cables ........................
Applying the VIM Vision Tools ...................
Chapter Summary ..............................
2-l
2-l
2-2
2-3
2-7
2-7
2-8
2-10
2-10
2-10
2-11
2-13
2-13
2-17
3 VIM System Theory of Operation
Chapter Objectives .............................
The VIM Module Imaging Process ................
Characteristics of Images .....................
Gray Levels ....................................
Gray-scale Conversion .......................
The VIM Module Gray Scale ..................
Binarization of Gray-Level Images ................
Setting Image Thresholds ....................
Reading Image Thresholds ...................
Brightness Probe Lightness Compensation ........
The Probe Operation ........................
The Probe Reference Patch ...................
LineGauges ...................................
Blobs .......................................
Line Gauge Measurements ......................
Line Gauge Measurement Pairs ...............
3-l
3-l
3-l
3-3
3-3
3-4
3-4
3-6
3-7
3-7
3-7
3-7
3-9
3-10
3-10
3-l1

2 Table of Contents
-
Chapter Title
3 (cont.) Edge Measurements . . . . . . . . . . . . . . . . . . . . . . . .
Center Measurements . . . . . , . . . . . . . . . . . . . . . . .
Width Measurements
Count BlackWhite Pixels’ ’ : : : : : : 11: : : : : 1:: 1: : :
Count Number of Blobs . . . . . . . , . . . . . . . . . . . . . . . . .
Count Number of Edges . . . . _. . . . __. . . . . __. . . . __
Using Line Gauge Filters . . . . . . . . . . . . . . . . . . . . . . . .
X/Y Float Gauges . . . . . . . . . . . __. . . . . __, . . . _. . . . . _
Window Measurements . . . . _. . . . . . . _. . . . . _. . . . .
Setting Windows . . . . . . . . . . . . . . . . . . . . . . . . . . .
Counting Pixels . . . . _. . . . _. . . . . . . _. . . . . _. . . . .
PLCCommunications Overview . . . . . . . . . . . . . . . . . .
Discrete Bit Communications . . . . . . . . . _. . . . . __
Block Transfer Communications . . . . . . . . . _. . . .
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-12
3-15
3-17
3-19
3-20
3-21
3-22
3-24
3-24
3-24
3-25
3-26
3-26
3-26
3-27
4 Staging for Vision Applications
ChapterObjectives .............................
Forming the Image .............................
Focus ......................................
Image Contrast .............................
The importance of Illumination .................
Different Types of Illumination ..................
Methods of Illumination ........................
Direct Illumination ..........................
Indirect Illumination ........................
Lens Selection and Adjustment ..................
How a Lens Works ..........................
Selecting the Lens for Your Application ..........
Using the Lens Selection Table ..................
Lens Selection if FOV is Known ...............
Lens Selection if Accuracy is Known ...........
Lens and Camera Set-up ........................
Object Positioning .............................
Still Objects ................................
Moving Objects .............................
4-l
4-l -
4-l
4-2
4-2
4-4
4-5
4-5
4-6
4-7
4-7
4-10
4-12
4-12
4-12
4-12
4-14
4-14
4-14
5 Installation and Integration
ChapterObjectives . . . . . . . . . . . . . . . . . . . . . .._.....
Integration of VIM Components . . . . _. . . . . _. . . . . _
Requirements for Installation Into an
Existing PLC 1771 I/O Rack . . . . . . . . . . _. . . _.
5-l
5-l
5-l

Table of Contents 3
Chapter Tit/e
5 (cont.) Requirements for Installation Into a
1771 Standalone I/ORack ....................
I/O Rack Installation .........................
Power Supply Installation ....................
VIM Module Installation .....................
CameraComponent Installation ..............
Light Pen installation ........................
Video Monitor Installation ...................
Strobe Light Connection .....................
Swingarm .....................................
Swingarm Connections ......................
Swingarm Installation .......................
Grounding Considerations ...................
Indicator Lights (LED’s) .........................
Integrating aVIM System With Your Process ......
Defining Your Interface Requirements ........
The Discrete Data Interfaces ....................
Swingarm Field Wiring Discrete
Datalnterface ..........................
Discrete Bit Communications to the PLC .......
BlockTransfers ................................
Configuration Blocks ........................
ResultsBlock ...............................
Addressing the Discrete Bits
From a PLC Program .....................
PLC Control of the VIM System ..................
Bit Manipulation ............................
Bit Manipulation Example 1: .................
Bit Manipulation Example 2: .................
PLC Block Transfer Interface .....................
BlockLength ...............................
Typical Inspection Handshake Sequence .......
Inspection Cycletime ........................
Displaying the Results Block ..................
Results Block Format ........................
Block Transfer Numbering Systems ............
Push-button Triggering .........................
“Single Shot” Push Button ...................
“Continuous” Push Button ...................
Page
5-2
5-2
5-2
5-2
5-5
S-10
S-10
5-11
5-11
5-11
5-13
5-14
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S-20
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5-23
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5-24
5-25
5-27
5-28
S-30
5-31
5-32
5-35
5-35
5-36
6 htroduction to the User interface
Chapterobjectives ............................. 6-l
The Icon Interface .............................. 6-l
How the Icon system works .................. 6-2
Commonly Used Icons .......................... 6-3

4 Table of Contents
Chapter Title -
Page
6 (cont.) Removing Icon Strips and Displaying Analog
Images .....................................
Changing the Run-Time Display .................
The Menu Branching Map ......................
Main Software Branches ........................
The Menu Branching Diagram ................
Points to Remember When Using the
Menus and Icons ............................
Chapter Summary ..............................
6-5
6-5
6-6
6-7
6-7
6-7
6-8
7 User interface Reference Section
Chapter Objectives .............................
The Sign-on Banner ............................
MainMenuTasks ..............................
TheMainMenu ................................
The Brightness Branch ..........................
Brightness Branch Tasks ........................
The Brightness Main Menu ......................
The Probe Move Menu .........................
The Probe Hi/Lo Range Menu ...................
The Threshold Adjust Menu .....................
The Line Gauge Menu Branch ...................
The Line Gauge Tasks ...........................
The Line Gauge Main Menu .....................
The ETC Line Gauge Menu ......................
The Line Movement Menu ......................
The Line Size Menu ............................
The Line Hi/Lo Range Menu .....................
The Window Branch ............................
The Window Tasks .............................
The Window Main Menu .......................
The ETCWindow Menu .........................
The Window Move Menu .......................
The Window Size Menu ........................
Window Sizing Characteristics ................
The Window Hi/Lo Range Menu .................
7-l
7-l
7-2
7-3
7-7
7-8
7-9 -
7-13
7-15
7-19
7-23
7-24
7-25
7-31
7-37
7-39
7-41
7-45
7-46
7-47
7-51
7-53
7-55
7-55
7-57
Appendix A Menu Branching Diagram
Appendix B Results Block Format

Table of Contents 5
FigurelTable Title Page
List of Figures
2.1
2.2
2.3
2.4
2.5
The Vision Input Module (VIM) . . . . . . . . . . . . . _. _. _.
The VIM Module Installed in a 1771 I/O Rack . . . . . . .
The VIM Module Installed in a Standalone
Rack Configuration . . . . . . . . . . . . . . . . . . . . . . .
VIM Module I/O Paths . . . . . . . . . . . . . _. . ___. _______
Easy Installation of Swingarm
Field Terminations . . . . . . . . . . . . . _. . . . . _. ___
LightPen . . . . . . . . ..__.._.....................___
Front Panel Features
CameraandLens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Video Monitor . . . . . . . . . _. . . . . . . . . . . . . . . . . . _. _. . .
Video Monitor Connections . . . . . . . . . . . . . . . . . _. . . _
The VIM Module, Peripherals, and Cables . _. _. __. . _
Hole Presence Verification Using a Circular
Window Image of a Properly
Punched Hole _____. . . . . . . . . . . . . . . . __. _. __. _.
Hole Presence Verification Using a Circular
Window Image of an Improperly
Punched Hole . . . . . _. . . . . . . . . . . . . . . . . . . _. . . . .
Line Gauge Check for Proper
Label Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stripped Wire ImageShowing Line Gauge
Placement . . . . . . .._.__....................__.
2-l
2-4
2-5
2-6
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2-7
2-8
2-9
2-10
2-11
2-11
2-12
2-14
2.13
2-14
2.14
2.15 2-15
2-16
3.1
3.2 Pixels Arranged in Rows and Columns ............. Image Scanning Pattern and Image
Coordinates .................................
Four Grays Converted to Digital Values ............
Gray-level (Analog) Image .......................
Binarized Image With a
LowThreshold ...............................
Binarized Image With a
High Threshold ..............................
The Probe as Seen in the Video Monitor
DuringSetup ................................
The Probe Reference Patch Seen in the
Live Video Image ............................
Pixels and Corresponding Digital Values ...........
Black and White “Blobs” .........................
Line Gauge Function One Measuring the
Left/top Edge of the Largest Blob ..............
Line Gauge Function Four Measuring the
Left/top Edge and Width of the Leftflop Blob ...
Edges for a Black Blob ...........................
Line Gauge Function Two - Measuring the Center
of the Largest Blob ...........................
Line Gauge Function Five - Measuring the Center
of the Left/top Blob ..........................
3-l
3.3
3.4
3.5
3-2
3-3
3-4
3-5
3.6 3-6
3.7 3-8
3.8
3.9
3.10
3.11
3-8
3-9
3-10
3-12
3.12
3.13
3.14
3.15
3-13
3-13
3-15
3-15

6 Table of Contents
Figure/Table Title
3.16
3.17
3.18
3.19
Center for a Black Blob . . . . . . . . . . . . . . . . . . . . . . . . . .
Line Gauge Function Three Measuring the
Width of the Largest Blob . . . _. . . . . . . . . . . . . . _. .
Line Gauge Function Five Measuring the Width
of the Left/top Blob . . . . . . . _. . . . _. . . . . . , . . . . . .
Width of a Black Blob . . . . . . . . . _. . . . . . . . . . . . . . . . .
4.1
4.2
4.3
4.4
4.5
4.6
Specular and Diffuse Reflection . . . . . . . . . . . .
Example of Diffuse Backlighting . . . . . . . . . . . .
Examples of Indirect Illumination . . . . _. . . . . .
Relationship of the Focal Length of a Lens to
Standoff Distance Given a Constant Field
ofView . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control of Light Collection Using the F-stop
oftheLens . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AspectRatio . . . . . . . . . . . . . . . . . . . . . . . . . . . .._
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
5.15
5.16
5.17
5.18
5.19
5.20
5.21
5.22
5.23
5.24
Installation of Keying Bands .....................
Configuration Plug Settings ......................
Installation of the VIM Module ...................
Camera Configurations ..........................
VIM Front Panel Features ........................
Camera I/O Locations ............................
VIM Power Supply ..............................
12lnchMonitor .................................
Swingarm - Field Wiring Terminals ___. . __. . ___. . __
Installation of the Swingarm .....................
Swingarm Latch Connection .....................
Instruction Addressing Terminology ..............
Instruction Addressing Example ..................
PLC Bit Manipulation Menu Used
to Force Control Bits ..........................
Rapid Firing of the VIM Under PLC Control .........
Free-Running Timer .............................
VIM Module Handshake Cycle ....................
Inspection Cycle Times ...........................
Results Block Display in Binary Format .............
Results Block Display in Hexadecimal Format .......
Binary Numbering ..............................
BCD Word Format ...............................
“Single Shot” Push-button Circuit ................
“Continuous” Push-button Circuit ................
6.1
6.2
6.3
6.4
6.5
6.6
“Picking” an Icon Using the Light Pen ...........
The Main Menu Shown asa Typical Icon Menu . . _
Brightness Main Menu Access Icon ..............
Window Main Menu Access Icon ................
Strobe Enabled Icon ...........................
Strobe Disabled Icon ..........................
. . . . 4-3
. . . . 4-5
. . . . 4-6
. . . .
. . . .
. .
-
Page
3-16
3-17
3-17
3-18
4-8
4-9
4-11
5-3
5-4
5-5
5-6 _
5-7
5-8
5-9
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6-3
6-3

Table of Contents 7
Figure/Table Tit/e
6.7
6.8
6.9
6.10
6.11
6.12
6.13
6.14
Page
“0K”lcon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
ETC(etcetera)lcon ._..._........................ 6-4
ETC Icon as Seen on the Line Gauge Main Menu . . . . 6-4
ETC Icon as Seen on the ETC Line Gauge
Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
The Window Move Menu Arrow Icons Used
to Move Window Position . . . . . . . . . . . . . . . . . . . . 6-4
The Window Size Menu Arrow Icons Used
to Change Window Size . . . . . . . . . . . . . _________ 6-5
The Three Main Branches of the VIM Menu . . . . . . . _ 6-6
Menu Branching Diagram . . . . . . . _. _. __. _. . _. . . . . 6-9
l.A List of Tables
VIM Module User’s Manual Organization . . . . . . . . . . l-l
4.A Lens Selection Table . . . . . . . . . . . . . . . . . . . . . . . . . _. . _ 4-l 3
5.A
5.B
5.c
5.D
5.E
Discrete Bits Description Decisions . . . . . . . . . . . . . . . . 5-19
Results Block 1 of 1
(Block Length of 59 Words) . . . . . . . . . . . . . . . . . . . 5-37
Configuration Block 1 of 3
(Block Length of 30 Words) . . . . . . . . . . . . . . . ___. 5-41
Configuration Block 2 of 3
(Block Length of 62 Words) . . . . . . . . . . . . . _. ____ 5-43
Configuration Block 3 of 3
(Block Length of 63 Words) . . . . . . . . . . . . . . . . . . . 5-45

Chapter I Using ThisManual
-
Chapter Objectives This chapter provides an overview of the contents of this
manual. It also contains: a definition of the intended
audience; an introduction to vision vocabulary; warnings,
cautions and other important information; information on
related publications; and updates on revisions to the
manual.
What this Mama/ This manual provides reference information on the Allen-
Contabs Bradley Vision Input Module, commonly referred to as the
VIM module. It includes instructions and reference
information needed to successfully operate a VIM system.
Table l.A provides a quick overview of the organization of
this manual.
Table 1.A
VIM Module User’s Manual Organization
C
hapter 1 Title Summary
1 Using This Manual This chapter includes chapter
overviews, audience definition,
major terms, cautions, related
publications, and revision
information.
2 Introduction to the This chapter introduces you to the
Vision Input Module software and hardware features,
(VIM) provides hardware descriptions,
and shows application examples.
3 VIM System Theory This chapter introduces the
of Operation operating principles behind the
vision tools and provides advice
on setting acceptance range
limits.
4 Staging for Vision This chapter discusses vision
Applications application principles such as;
image quality, lighting, lenses,
and setup.
5 Installation and This chapter provides instruction
Integration on the proper installation and
integration of VIM system
components.
6 Introduction to the This chapter introduces you to the
User Interface operator interface and provides
an overview of the software.
7 User Interface This chapter provides a complete
Reference Section reference source for the VIM
module menu and icon functions.

l-2 Chapter 1 Using This Manual
-
Audience No computer programming experience is required in order
to learn to use the VIM module. However, past experience
in PLC operations will greatly enhance your ability to
integrate the VIM module into existing PLC systems. If you
are installing the module in a PLC system you should be
familiar with the Allen-Bradley line of PLCs and have some
Ladder-Logic programming experience.
Vocabulary There are terms in this manual which are commonly used in
the machine vision industry and others which are specific to
the VIM vision system. These and other key terms are
defined below:
l Acceptance Range - The range of values that are
accepted for vision tool range tests. The acceptance range
is defined by high and low range limits.
l Blob - A group of contiguous (adjacent) white or black
pixels along a line of pixels in an image. The line gauges
in the VIM module make edge, center, and width
measurements for blobs. A complete explanation of blob
measurement is provided in Chapter 3, “VIM System
Theory of Operation.”
l Block Transfer - A Block Transfer is a method of
communicating a “block” of data between a PLC and an
UO module. In this case, the I/O module is the VIM
module and the block of data includes individual
measurement results data and configuration data. All
block transfers are invoked by an instruction from the
PLC controller.
l Brightness Probe - A sample area of the image used to
measure light intensity or “brightness.” This probe can be
used to:
- Measure the brightness of a small section of the image.
- Detect lighting changes and compensate for variation;
l Column - A row of pixels in the vertical (Y) direction in
the image or on the display screen.
l Configuration Block - A block of data that may be
uploaded to, or downloaded from, a PLC controller. This
block contains configuration information about
measurement windows, line gages, the brightness probe,
and other setup information.

Chapter 1 Using This Manual 7-3
- Vocabulary One of the more important aspects of the VIM module is
(con timed) that configuration data can be transferred in blocks to and
from the PLC controller. As a result, configuration data
may be sent to the PLC controller, the VIM module removed
and replaced, and the replacement module easily
reconfigured.
l Contrast-The brightness difference between the
workpiece and the background as seen in the image. Good
contrast is important for reliable operation of the vision
tools used in the VIM module.
l Depth of Field -The range in which objects focus clearly.
It is measured from the distance beyond the ideal focal
point to the distance in front of it in which objects remain
in focus.
l Field of View -The angle of view that is seen through a
lens or optical instrument. The distance from the left to
the right edge of the visible space.
-
l Field (Video) -A single scan of the video camera image.
The camera produces a steady stream of video fields, each
consisting of a series of scan lines (rasters).
l Gray Scale -A measure of relative brightness from
black, through many increments of gray, to white.
l Icon -A symbolic, pictorial representation of a command.
“Picking” an icon with the Light pen triggers the
command. Typical icons include Move Up and Move
Down arrow icons that are used to move objects on the
screen. These icons look like arrows pointing up and
down. The icon system is explained in Chapter 6,
“Introduction to the User Interface.”
l Light Pen -The input device used to interact with the
VIM module. It’s used with the video monitor to “pick”
icons and menus and to configure the system to meet your
application needs. The light pen is shaped like a pen and
has a cord that attaches to the VIM module face during
setup. The pen responds to the emitted light as images
are scanned onto the screen -- explaining the name “Light
Pen.”

1-4 Chapter 1 Using This Manual
Vocabulary l Line Gauge - Line gauges are one of the vision tools in
(continued) the VIM module. A Line Gauge is a set of horizontally or
vertically aligned pixels (found in a row or column). The
user sets the length, direction, and position of the line
gauges. There are twenty-two line gauges available in
the VIM module plus two XY positioning gauges. For a
complete explanation of Line Gauge operation, refer to
Chapter 3.
l Master Range Alarm - The Master Range Alarm
(Decison bit) is a discrete output which indicates the
ACCEPT/REJECT status of an inspection. It is available
to both the PLC controller and through the swingarm.
l Pick -The action of “picking” a displayed icon or value by
pressing the tip of the Light pen against its location on the
screen.
l Pixel - One picture element (or dot) in an image. The
image is a matrix of pixels.
l Range Alarm - The response generated when a
measurement falls outside its Hi/Lo acceptance range.
The Range Alarm status is communicated through the
results block, and/or by a discrete output (master range
alarm) via the swingarm or backplane.
Note: Each “Vision Tool” (brightness probe, windows,
and line gauges) has a range alarm bit. The master range
alarm outputs an accept/reject after an inspection.
l Range Limit - The high and low range limits define the
range of variation that can be tolerated above and below
the nominal value. Range limits are defined by the user.
l Results Block - A block transfer table initialized by the
VIM module to communicate the results of an inspection.
This block contains information indicating the
accept/reject status of acceptance range tests for the
brightness probe, measurement windows, and line
gauges. The actual probe luminance gray value, pixel
counts for each window, and line gauge results for each
line gauge are communicated through the Results Block.
The VIM module generates one result block for each
picture analysis cycle.
l Row - A line of pixels across the image in the horizontal
(X) direction.
l Swingarm - A screw terminal connector installed on the
front panel of many 1771-I/0 modules, including the VIM
module. It’s used to connect wires to the module.

Chapter 1 Using This Manual 7-5
Vocabulary l Threshold - A gray level used to transform a gray-scale
(con timed) video image into a binary image. Pixels whiter than the
threshold are converted to white (l), values darker or
equal to the Threshold are converted to black (0).
l Vision Tool - The VIM vision tools include the
brightnessprobe, line gauges, and windows. Vision tools
are used to take measurements and generate accept/reject
decisions. See Chapter 3, “VIM System Theory of
Operation” for an explanation of Vision Tool operations.
l Window -Windows are shapes which define localized
image areas to be used for measurement operations. The
user defines the window size, shape, and location. The
vision operation used in VIM windows is area
measurement by pixel counting.
l Workpiece - The item to be inspected by the VIM
module.
l Workstage - The area viewed by the camera.
Warnings and Warnings and Cautions occasionally appear in this
Cautions document. They are included in order to protect both you
and the equipment. They appear as follows:
A
1Warning: A warning symbol means that people
l might be injured if the stated procedures are not
followed.
A
1Caution: A caution symbol is used when the
l equipment could be damaged or performance
seriously impaired if stated procedures are not
followed.

1-6 Chapter 1 Using This Manual
-
Related Pub/ications The following Allen-Bradley documents contain VIM
module related information. Each document is referenced
where appropriate. Consult your local Allen-Bradley
representative for ordering information.
Vision Input Module, Self Teach Manual -
Publication Number 2803819
Grounding and Wiring Guidelines -
Publication Number 1770-4.1
Mounting Instructions for 1771 I/O Chassis and
Power Supply -
Publication Number 1771-4.5
PLC 5/15 Processor Manual -
Publication Number 1785-6.8.1
PLC 5/15 Assembly and Installation Manual -
Publication Number 1785-6.6.1
Solid State Control, General Information -
Publication Number SGI- 1.1
A System of Universal I/O -
Publication 1771-1.2
Mounting Dimensions for 1771 I/O Chassis and
Power Supplies -
Publication 1771-4.5
PLC Controllers 2/16 and 2/17 Processor
User Manual -
Publication 1772-6.5.8
Other VIM module related documentation may be ordered
as needed.
Revision lnforma tion This is the first release of this manual. No revisions have
been made to date.

Chapter 2 introduction to the
Vision Input Module (VIM)
-
Chapter Objectives In this chapter, we will familiarize you with the features,
functions, installation, and application of the Vision Input
Module. To clarify subject matter, a summary is provided at
the end of the chapter.
What is the The Vision Input Module adds the power of Machine
Vision Input Module? Vision to the Allen-Bradley line of Programmable Logic
Controllers (PLC). It is a member of the “Universal I/O”
family of products. It gives you the ability to make non-
contact inspections and communicate the data to your PLC
system. The VIM module can inspect areas in a scene for
information such as workpiece presence or absence, and
make linear measurements to find edge and center locations
and feature widths. These measurements can be corrected
to accommodate variations in part position and workstage
lighting.
Figure 2.1
The Vision lmut Module (VIM)
The VIM module is a low-cost vision system -- providing a
new advantage in price and performance to industry. The
VIM module uses solid state video camera for image
collection. It’s easy to use, install and operate. VIM module

2-2 Chapter 2 Introduction to the Vision Input Module (VIM)
-What is the users who are familiar with PLC systems will find the VIM
Vision Input Module? module to be a natural extension of their PLC tool kit.
(continued)
The VIM module (Cat. No. 2803-VIMI) is a dual-slot
intelligent I/O module, which mounts into a standard 1771
I/O chassis. The VIM module can be integrated into your
process to inspect products and provide direct feedback to
the system’s PLC terminal for closed-loop process
management. The VIM module can also be operated as a
standalone vision system.
Sys tern
functional Features The VIM module comes complete with a set of image analysis tools which perform vision tasks. These tools let
you make four window measurements, brightness
measurements, and twenty-two line gauge measurements.
These capabilities are combined with the ability to close the
process loop through communications to PLC systems.
The vision tools are easily set up and controlled through
icons displayed on the screen. You simply “pick” the icon
that corresponds to the function you want to activate by
pressing the tip of the Light pen against it. The icons appear
in logically organized groups called “menus.” The menus
branch into other menus to allow you to complete different
set up procedures.
, Some notable features of the VIM module are:
Twenty-Two Line Gauge Measurements
Line gauges may be set to perform any of fifteen different
measurements. These include a variety of blob
measurements for edge, center, and width. They also
include counting operations for counting blobs, black or
white pixels, and edges. The line gauges are assigned in
pairs of measurements that complement each other. You
may assign an acceptance range to line gauge
measurements for accept/reject decisions.
Four Window Measurements
You may use up to four inspection windows to inspect
areas of interest in the image. Each window corresponds
to one of the thresholded images. The windows measure
surface area by counting black or white pixels. Each -.
window may be assigned a high/low acceptance range for
accept/reject decisions.

Chapter 2 introduction to the Vision Input Module (V/M) 2-3
.- Functional
Features
(continued)
Brightness Measurement
The brightness probe may be used to measure the
brightness of the workpiece or product and to make an
accept/reject decision. This tool might be used to test the
intensity of a light or the brightness of a painted surface.
Multiple Threshold Settings
The VIM module makes measurements based upon four
binarized images. Four independent binarization
thresholds may be set to provide four different versions of
the video image for inspection tasks. This versatility
allows you to enhance features that appear at different
gray levels.
Automatic Part Position Variation Adjustment
Two line gauges are used to automatically adjust for
variation in the workpiece’s position in the image. This
allows you to maintain measurement accuracy despite
small variations in workpiece position.
Automatic Lighting Adjustment
The “brightness probe” feature may be used to monitor
the light level on the workstage and adjust the image-
processing tasks to accommodate lighting variation.
Hardware The VIM module is a member of the “Universal I/O” family
Features of products. It uses the same racks, power supplies, and
swingarm terminations found in all Allen-Bradley PLC
1771 systems.