Rockwell Automation 2755-L7, 2755-L9 User Manual
ALLEN-BRADLEY
Bulletin 2755 Industrial Medium and
High-Spped Bar Code Scanners
(Catalog Numbers 2755-L7SA, -L7RA, -L7SB, -L7RB,
-L7SC, -L7SD, -L7RD, -L9SA, -L9RA, -L9SB, -L9RB,
-L9SD, -L9RD)
User Manual
Important User Information
Solid state equipment has operational characteristics differing from those of
electromechanical equipment. “Safety Guidelines for the Application,
Installation and Maintenance of Solid State Controls” (Publication SGI-1.1)
describes some important differences between 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 the 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, the 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.
Throughout this manual we use notes to make you aware of safety
considerations.
ATTENTION: Identifies information about practices or
circumstances that can lead to personal injury or death, property
!
damage, or economic loss.
Attentions help you:
• identify a hazard
• avoid the hazard
• recognize the consequences
Important: Identifies information that is especially important for successful
application and understanding of the product.
PLC is a registered trademark of Allen-Bradley Company, Inc.
Pyramid Integrator, DTL and CVIM are trademarks of Allen-Bradley Company, Inc.
MicroVAX, VAX and DECnet are registered trademarks of Digital Equipment Corporation.
VAXstation, VAXcluster and DECwindows are trademarks of Digital Equipment Corporation.
Table of Contents
A–B
Using This Chapter
Product Descriptions
Installation Considerations
Chapter 1
Chapter Objectives 1–1
Overview of This Manual 1–1
Intended Audience 1–2
Warnings and Cautions 1–2
Danger and Caution Labels 1–3
Chapter 2
Chapter Objectives 2–1
Overview 2–1
L7 Reading Ranges 2–2
L9 Reading Ranges 2–3
Features 2–4
Cabling 2–5
Accessories 2–6
Chapter 3
Installation
Chapter Objectives 3–1
How the Scan Head Operates 3–1
Positioning the Symbols Correctly 3–2
Usable Beam Length 3–5
Compensating for Pitched Symbols 3–6
Minimum Bar Width Adjustment 3–6
Code Element Distance 3–8
Chapter 4
Chapter Objectives 4–1
Warnings and Cautions 4–1
Before You Start 4–1
Tools You Will Need 4–1
Determining the Space Requirements 4–2
Mounting the Scan Head 4–2
Vibration Cautions 4–3
How to Install Swivel Mounting Base 4–3
Using the Flat Mounting Plate 4–4
Connecting Your Equipment 4–5
Installing the Package Detector Assembly 4–6
i
Table of Contents
Operation
Maintenance and
Troubleshooting
Specifications
Chapter 5
Chapter Objectives 5–1
Warnings and Cautions 5–1
Laser On/Off Control 5–1
Scan Width Adjustment 5–2
Scan Width Adjustment Procedure 5–2
Raster Height Adjustment 5–3
Raster Height Adjustment Procedure 5–4
Chapter 6
Chapter Objectives 6–1
Maintaining the Equipment 6–1
Scan Window Removal 6–1
Cleaning the Glass Window 6–2
Cleaning the Plastic Window 6–3
Troubleshooting the System 6–4
Chapter 7
Scan Head 7–1
Glossary G–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Index I–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ii
Chapter
Chapter Objectives
Overview Of This Manual
A–B
1
Using This Manual
Read this chapter to familiarize yourself with the rest of the manual. You will learn
about:
• Contents of the manual.
• Intended audience.
• Warnings and cautions.
This manual is for Catalog Nos. 2755–L7SA, –L7SB, –L7SC, –L7SD,
–L7RA, –L7RB, –L7RC, –L7RD Industrial Medium–Speed Bar Code
Scanners and Catalog Nos. 2755–L9SA, –L9SB, –L9SD, –L9RA, –L9RB,
and –L9RD Industrial High–Speed Bar Code Scanners.
Chapter Title Purpose
1 Using This Manual
2 Product Description
3 Installation Considerations
4 Installation Installation procedures.
5 Operation
6
7 Specifications
- Glossary
Maintenance and
Troubleshooting
Provides an overview of the
manual.
Features and capabilities
are described.
Things you should know
and understand before
installing your scanner.
Operating procedures and
beam adjustments.
Maintenance and
Troubleshooting guidelines
are provided.
Electrical, mechanical,
environmental and
operational information is
listed.
- Index
1–1
Chapter 1
Using this Manual
Intended Audience
Warnings And Cautions
No special knowledge is needed to read this manual and follow its directions.
If the system will be used to communicate with a higher level controller, we
assume you are familiar with communication terminology.
Both warnings and cautions are found in this manual and on the equipment.
The following symbols are used:
CAUTION: This laser caution symbol appears where
laser radiation is present.
WARNING: A warning symbol means people might
be injured if the procedures are not followed.
Danger and Caution Labels
CAUTION: A caution symbol is used when
machinery could be damaged if the procedures are not
followed.
The scan head is labeled in accordance with federal regulations. If any label
is removed, lost, or becomes illegible, order a replacement from your
Allen–Bradley representative. Figure 1.1 shows location of the labels on the
scan head.
WARNING: No user maintenance of the scan head is required.
Do not open the enclosure!
!
WARNING: Improperly controlling, adjusting, or operating the
scan head can result in hazardous radiation exposure.
1–2
Chapter 1
Using this Manual
Figure 1.1
Location of Warning and Caution Labels on the Scan Head
1–3
Chapter
Chapter Objectives
Overview
A–B
2
Product Description
The capabilities of the scan head are described when connected to a Catalog
No. 2755–DM9 Decoder.
The Industrial Medium and High Speed Bar Code Scanners are moving
beam, bar code scan heads designed for use with the Catalog No. 2755–DM9
Decoder. The scanners are available as shown:
• Side scanning (Catalog No. 2755–L7Sx①, –L9Sx①)
• Side Raster scanning (Catalog No. 2755–L7Rx①, –L9Rx①)
① The x stands for the different range selections of each scanner. Refer to Figures 2.2 and 2.3.
Scanning is bidirectional at approximately 350 scans per second with an L7,
Industrial Medium–Speed Bar Code Scanner and 800 scans per second with
an L9, Industrial High–Speed Bar Code Scanner. Depending on the scanner
used, symbols can be scanned as near as 3.5 inches (8.9 cm) and as far as 50
inches (127 cm) away.
Figure 2.1
Side Scanning and Raster Scanning
90–105–9
The side scanning model reflects the scanning beam out of the side of the
NEMA 4 case.
The raster scanning model uses a stepping raster motor to project what
appears to be a number of parallel beams out the side of the unit. This type
of scan head is useful when attempting to scan poor quality labels, or labels
that may not always be in exactly the same place.
2–1
Chapter 2
Product Description
L7 Reading Ranges
Figure 2.2 illustrates the average reading ranges, relative to the symbol’s
minimum bar width, that you should expect when using an L7 scanner with
your Catalog No. 2755–DM9 Decoder.
Figure 2.2
Average Scan Range vs. Minimum Bar Width for L7 Scanner
Minimum Bar Width
Mils
Millimeters
50
1.27
45
1.14
40
1.02
35
.89
30
.76
25
.64
20
.51
15
.38
10
.25
5
.13
2755–L7SC
2755–L7RC
2755–L7SD
2755–L7RD
2755–L7SB
2755–L7RB
2755–L7SA
2755–L7RA
2–2
Inches
Centimeters
12.7
① Scan Range will vary with symbol quality, pitch and skew. This application was based on no more than 5 ° pitch and 30° skew, with full scan beam
(Figure 5.3). Refer to Chapter 3, Installation Considerations when reading labels with more than 20° pitch.
10
5
38.1
25.4
Scan Range (from face of scanner)
15
20
50.8
63.5
25
30
76.2
88.9
35
①
40
101.6
114.3
45
50
127.0
The following table compares the minimum bar width to the scan range of
each catalog number.
Minimum Bar
Width
Mils mm Inches Centimeters Side Scanning
7.5
10
20
11
20
25
16
25
35
20
35
50
① When using ‘‘A’’ range scanners to read labels with high paper noise, increasing the skew to 25 will enhance performance.
.19
.25
.51
.28
.51
.64
.41
.64
.89
.51
.89
1.27
Scan Range
6.5 – 8.5
6.0 – 9.0
5.0 – 11.0
8.5 – 13.5
5.5 – 19.0
3.5 – 22.0
10 – 23
8 – 29
6 – 35
16 – 35
8 – 50
8 – 50
① Catalog Number
16.5 – 21.6
15.2 – 22.9
12.7 – 27.9
21.6 – 34.3
14.0 – 48.3
8.9 – 55.9
25.4 – 58.4
20.3 – 73.7
15.2 – 88.9
40.6 – 88.9
20.3 – 127
20.3 – 127
2755–L7SA① 2755–L7RA①
2755–L7SB 2755–L7RB
2755–L7SD 2755–L7RD
2755–L7SC 2755–L7RC
Raster
Scanning
Chapter 2
Product Description
L9 Reading Ranges
Figure 2.3 illustrates the average reading ranges, relative to the symbol’s
minimum bar width, that you should expect when using an L9 scanner with
your Catalog No. 2755–DM9 Decoder.
Figure 2.3
Average Scan Range vs. Minimum Bar Width for L9 Scanner
35
.89
30
.76
25
.64
20
.51
15
.38
10
.25
5
.13
2755–L9SD
2755–L9RD
2755–L9SB
2755–L9RB
2755–L9SA
2755–L9RA
Minimum Bar Width
Mils
Millimeters
Inches
Centimeters
① Scan Range will vary with symbol quality, pitch and skew. This application was based on no
more than 5°pitch and 30° skew, with full scan beam (Figure 5.3). Refer to Chapter 3, Installation
Considerations when reading labels with more than 20° pitch.
5
12.7
10
25.4
Scan Range (from face of scanner)
15
38.1
20
50.82563.53076.23588.9
①
The following compares the minimum bar width to the scan range of each
catalog number.
Minimum Bar Width Scan Range② Catalog Number
Mils mm Inches Centimeters
7.5
10
20
11
20
25
16
25
35
② Scan range will vary with symbol quality. This application was based on no more than 5° pitch and 30° skew with
full scan beam (Figure 5.3). Refer to Chapter 3, Installation Considerations when reading labels with more than 20°
pitch.
③ Scan range may be reduced when using low contrast labels.
.19
.25
.51
.28
.51
.64
.41
.64
.89
6.5 – 8.5
6.0 – 9.0
5.0 – 11.0
10 – 13.5
9 – 16
8.5 – 18
10.5 – 21.5
9.0 – 25.5
7.5 – 30③
16.5 – 21.6
15.2 – 22.9
12.7 – 27.9
25.4 – 34.3
22.9 – 40.6
21.6 – 45.7
26.7 – 54.6
22.9 – 64.8
19.1 – 76.2③
Side
Scanning
2755–L9SA① 2755–L9RA①
2755–L9SB 2755–L9RB
2755–L9SD 2755–L9RD
Raster
Scanning
2–3
Chapter 2
Product Description
Features
Laser Shut Off – Use this switch to enable/disable the laser beam without
interrupting power. The upward position (ON) enables the laser, the
downward position (OFF) disables the laser beam. The use of this feature is
covered in Chapter 5, Operation.
LED indicators – There are two LEDs on the back of the scan head, Power
On and Valid Read. They are defined in Figure 2.4.
Figure 2.4
Scan Head Features
2–4
NEMA 4 Case – Both the L7 and L9 scan heads are housed in gasketed,
NEMA 4, aluminum cases.
Replaceable Scan Windows – You can easily remove and replace the scan
windows. Both the L7 and L9 scan heads are shipped with coated, optical
quality, glass windows. Coated, low loss, optical quality, plastic windows
are also available for special applications, or when required by FDA
regulations. The use of this feature is covered in Chapter 6, Maintenance
and Troubleshooting.
Package Detector Port – Connect the optional Package Detector Assembly
(Catalog No. 2755–NP3, or NP5) to this port to allow the scan head to be
turned on only when there is a package present.
The use of this feature is
covered in Chapter 4, Installation.
Scan Width Adjustment – This four position switch is located behind a
gasketed 1/4–20 screw. Rotate this switch, using the supplied tool, to set the
scan width to one of four settings: full,
, , .
Examples of this feature are
covered in Chapter 5, Operation.
Raster Height Adjustment – This four position switch is located behind a
gasketed 1/4–20 screw. Rotate this four position switch to increase/decrease
the height of your raster scanning pattern (on L7R and L9R only). Examples
of this feature are covered in Chapter 5, Operation.
Figure 2.5
Scan Head Features
Chapter 2
Product Description
Cabling
Accessories
Scanner to Decoder cables are sold separately. Refer to Table 2.C for
information necessary to order the proper cable.
Several accessories are available to provide installation and operational
flexibility, including:
• Package Detector Assembly – This assembly consists of a Package
Detector Switch and a reflector. This switch indicates to the decoder that
a package is present.
• Mounting hardware – A swivel ball mounting base is available for use
with a flat mounting plate or “T” Mounting plate.
• Replaceable Windows – Replaceable, optical quality, glass and plastic
windows are available.
2–5
Chapter 2
Product Description
The following table lists system accessories.
Catalog
Number
2755–NP3
2755–NP5
2755–NC9
Long Range Package
Detector Assembly
Short Range Package
Detector Assembly
Package Detector Port
Connector
2755–NM1 Swivel Mounting Base
Item Description
An infrared photoelectric switch and reflector. For the
detection of packages up to a maximum of 18 feet
(5.5 m) away.
A visible red photoelectric switch and reflector. For the
detection of packages up to a maximum 10 feet (3 m) away.
Connects user–supplied photoelectric switch to scan head.
Accepts cables with .190 to .312 inches
(4.8 to 7.9 mm) outer jacket diameter.
Universal swivel ball mount for greater installation flexibility.
Must be used with “T” Mounting Plate or Flat Mounting Plate.
2755–NM2 “T” Mounting Plate
Mounts Swivel Mounting Base (Catalog No. 2755–NM1) to
scan head.
Attach this plate to scan head in order to use your own
2755–NM3 Flat Mounting Plate
brackets, or to use the Swivel Mounting Base (Catalog No.
2755–NM1) when you want the swivel ball close to the base
of the scan head.
2755–CL10 10 foot (3 meter) Cable Connects scanner to Catalog No. 2755–DM9 Decoder.
2755–CL25 25 foot (7.6 meter) Cable Connects scanner to Catalog No. 2755–DM9 Decoder.
W77121–800–01①
W77121–800–02①
W77121–802–01①
W77121–802–02①
① Replacement part number.
2–6
Replacement Glass
Window Kit
Replacement Plastic
Window Kit
Caution & Warning Label
Kit (English Only)
Caution & Warning Label
Kit (Alternate Language)
Anti–reflective, optical glass replacement window.
Hard coated, anti–reflective, optical quality, plastic
replacement window.
2755–L7, L9 - 5 sets per package.
2755–L7, L9 - 1 set each in German, French, Italian,
Spanish.
Chapter
Chapter Objectives
How thw Scan Head Operates
A–B
3
Installation Considerations
The operation of the scan head is briefly described. In addition, the
importance of proper symbol positioning and the effect pitch has upon a
symbol is also discussed.
Inside the scan head is the laser, the lens and mirror system and the
electronics. The laser generates a small, concentrated light beam that is
focused and projected through a window. This light is reflected by a symbol
and returned to the scan head for processing. The signal is then sent to the
decoder for further processing. Refer to Figure 3.1.
Figure 3.1
How the Scan Head Operates
T o Label
Reflected light
from symbol
(Diffuse Return)
3–1
Chapter 3
Installation Considerations
Positioning the Symbols Correctly
As the symbols move past the scan head, they must be correctly oriented.
The laser’s line of light must cut through all the bars and spaces in one
sweep.
Laser’s line of light
cuts through the
entire symbol
For example, if the scan head is mounted so the laser beam is in the vertical
direction, then the symbol must also be mounted vertically, commonly
known as the step ladder orientation. Figure 3.2 illustrates the step ladder
orientation.
Figure 3.2
Step Ladder Orientation
Label
Conveyor
Direction
3–2
If the scan head is mounted so the beam is in the horizontal direction, the
symbol must also be in the horizontal direction. This is termed picket fence
orientation.
Refer to Figure 3.3 for an example of the scan head and symbol in a picket
fence orientation.
Figure 3.3
Picket Fence Orientation
Label
Conveyor
Direction
Chapter 3
Installation Considerations
When setting up your scanner, you should attempt to have the laser line of
light nearly perpendicular to the bars and spaces of the symbol. For optimal
performance mount the scan head in a skewed position, 10° to 20° angle off
normal from the symbol, as shown in Figure 3.4.
Figure 3.4
Proper Mounting of Scan Head
Symbol
20°
10
°
Optimal angles
for scanning
beam
10°
20°
90°
20
90°
°
10°
10°
20°
Optimal angles for scanning
beam
The scan head can successfully decode symbols that are out of alignment,
provided that the projected, or apparent, bar element widths are within the
minimum widths shown in Tables 2.A and 2.B.
Symbols that are pitched or tilted up to ±45°, are still readable. Skewed
symbols can also be read as long as the misalignment is less than ±50°.
Figure 3.5 shows a correctly placed symbol as well as misaligned symbols.
Note: When using “A” range scanners to read labels with high paper noise,
increasing the skew to 25° will enhance performance.
WARNING: If at any time during operation an intense dot of
light is reflected onto a symbol instead of a line of light, turn the
!
scanner OFF with the toggle switch on the back of the scanner.
Then turn the decoder OFF.
3–3
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