Omron V520-LHA7127 User manual

MANUAL
USER
Cat. No. Q07BAZ1
V520-LHA7127
Miniature High Speed CCD
Fixed Position Scanner

V520-LHA7127
Miniature High Speed CCD
Fixed Position Scanner
User Manual

iv

v
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OMRON Electronics LLC 2003
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, o
r
by any means, mechanical, electronic, photocopying, recording, or otherwise, without the prior written permission o
f
OMRON.
No patent liability is assumed with respect to the use of the information contained herein. Moreover, because OMRON is con-
stantly striving to improve its high-quality products, the information contained in this manual is subject to change without
notice. Every precaution has been taken in the preparation of this manual. Nevertheless, OMRON assumes no responsibility
for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained in
this publication.

vi
Terms and Conditions of Sale
1. Offer; Acceptance. These terms and conditions (these "Terms") are
deemed part of all quotations, acknowledgments, invoices, purchase
orders and other documents, whether electronic or in writing, relating to
the sale of goods or services (collectively, the "Goods") by Omron Elec-
tronics LLC ("Seller"). Seller hereby objects to any terms or conditions
proposed in Buyer's purchase order or other documents which are incon-
sistent with, or in addition to, these Terms.
2. Prices. All prices stated are current, subject to change without notice by
Seller. Buyer agrees to pay the price in effect at time of shipment.
3. Discounts. Cash discounts, if any, will apply only on the net amount of
invoices sent to Buyer after deducting transportation charges, taxes and
duties, and will be allowed only if (i) the invoice is paid according to
Seller's payment terms and (ii) Buyer has no past due amounts owing to
Seller.
4. Interest. Seller, at its option, may charge Buyer 1-1/2% interest per
month or the maximum legal rate, whichever is less, on any balance not
paid within the stated terms.
5. Currencies. If the prices quoted herein are in a currency other than U.S.
dollars, Buyer shall make remittance to Seller at the then current
exchange rate most favorable to Seller and which is available on the due
date; provided that if remittance is not made when due, Buyer will con-
vert the amount to U.S. dollars at the then current exchange rate most
favorable to Seller available during the period between the due date and
the date remittance is actually made.
6. Governmental Approvals. Buyer shall be responsible for, and shall bear
all costs involved in, obtaining any government approvals required for the
importation or sale of the Goods.
7. Taxes. All taxes, duties and other governmental charges (other than gen-
eral real property and income taxes), including any interest or penalties
thereon, imposed directly or indirectly on Seller or required to be col-
lected directly or indirectly by Seller for the manufacture, production,
sale, delivery, importation, consumption or use of the Goods sold here-
under (including customs duties and sales, excise, use, turnover and
license taxes) shall be charged to and remitted by Buyer to Seller.
8. Financial. If the financial position of Buyer at any time becomes unsatis-
factory to Seller, Seller reserves the right to stop shipments or require
satisfactory security or payment in advance. If Buyer fails to make pay-
ment or otherwise comply with these Terms or any related agreement,
Seller may (without liability and in addition to other remedies) cancel any
unshipped portion of Goods sold hereunder and stop any Goods in tran-
sit until Buyer pays all amounts, including amounts payable hereunder,
whether or not then due, which are owing to it by Buyer. Buyer shall in
any event remain liable for all unpaid accounts.
9. Cancellation; Etc. Orders are not subject to rescheduling or cancellation
unless Buyer indemnifies Seller fully against all costs or expenses aris-
ing in connection therewith.
10. Force Majeure. Seller shall not be liable for any delay or failure in deliv-
ery resulting from causes beyond its control, including earthquakes,
fires, floods, strikes or other labor disputes, shortage of labor or materi-
als, accidents to machinery, acts of sabotage, riots, delay in or lack of
transportation or the requirements of any government authority.
11. Shipping; Delivery. Unless otherwise expressly agreed in writing by
Seller:
a. Shipments shall be by a carrier selected by Seller;
b. Such carrier shall act as the agent of Buyer and delivery to such
carrier shall constitute delivery to Buyer;
c. All sales and shipments of Goods shall be FOB shipping point (unless
otherwise stated in writing by Seller), at which point title to and all risk
of loss of the Goods shall pass from Seller to Buyer, provided that
Seller shall retain a security interest in the Goods until the full
purchase price is paid by Buyer;
d. Seller may over or under ship by up to 3% of the scheduled quantity.
Exact quantity orders will be accepted at a 5% unit price premium.
e. Delivery and shipping dates are estimates only.
f. Seller will package Goods as it deems proper for protection against
normal handling and extra charges apply to special conditions.
12. Claims. Any claim by Buyer against Seller for shortage or damage to the
Goods occurring before delivery to the carrier must be presented in writ-
ing to Seller within 30 days of receipt of shipment and include the original
transportation bill signed by the carrier noting that the carrier received
the Goods from Seller in the condition claimed.
13. Warranties. (a) Exclusive Warranty. Seller's exclusive warranty is
that the Goods will be free from defects in materials and workman-
ship for a period of twelve months from the date of sale by Seller.
Seller disclaims all other warranties, express or implied. (b) Limita-
tions. SELLER MAKES NO WARRANTY OR REPRESENTATION,
EXPRESS OR IMPLIED, ABOUT NON-INFRINGEMENT, MERCHANT-
ABILITY OR FITNESS FOR A PARTICULAR PURPOSE OF THE
GOODS. BUYER ACKNOWLEDGES THAT IT ALONE HAS DETER-
MINED THAT THE GOODS WILL SUITABLY MEET THE REQUIRE-
MENTS OF THEIR INTENDED USE. Seller further disclaims all
warranties and responsibility of any type for claims or expenses
based on infringement by the Goods or otherwise of any intellec-
tual property right. (c) Buyer Remedy. Seller's sole obligation here-
under shall be to replace (in the form originally shipped with Buyer
responsible for labor charges for removal or replacement thereof)
the non-complying Good or, at Seller's election, to repay or credit
Buyer an amount equal to the purchase price of the Good; provided
that in no event shall Seller be responsible for warranty, repair,
indemnity or any other claims or expenses regarding the Goods
unless Seller's analysis confirms that the Goods were properly han-
dled, stored, installed and maintained and not subject to contami-
nation, abuse, misuse or inappropriate modification. Return of any
goods by Buyer must be approved in writing by Seller before shipment.
14. Damage Limits; Etc. SELLER SHALL NOT BE LIABLE FOR SPE-
CIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, LOSS OF PROF-
ITS OR PRODUCTION OR COMMERCIAL LOSS IN ANY WAY
CONNECTED WITH THE GOODS, WHETHER SUCH CLAIM IS
BASED IN CONTRACT, WARRANTY, NEGLIGENCE OR STRICT LIA-
BILITY. Further, in no event shall liability of Seller exceed the indi-
vidual price of the Good on which liability is asserted.
15. Indemnities. Buyer shall indemnify and hold harmless Seller, its affiliates
and its employees from and against all liabilities, losses, claims, costs
and expenses (including attorney's fees and expenses) related to any
claim, investigation, litigation or proceeding (whether or not Seller is a
party) which arises or is alleged to arise from Buyer's acts or omissions
under these Terms or in any way with respect to the Goods. Without lim-
iting the foregoing, Buyer (at its own expense) shall indemnify and hold
harmless Seller and defend or settle any action brought against Seller to
the extent that it is based on a claim that any Good made to Buyer spec-
ifications infringed intellectual property rights of another party.
16. Property; Confidentiality. The intellectual property embodied in the
Goods is the exclusive property of Seller and its affiliates and Buyer shall
not attempt to duplicate it in any way without the written permission of
Seller. Notwithstanding any charges to Buyer for engineering or tooling,
all engineering and tooling shall remain the exclusive property of Seller.
All information and materials supplied by Seller to Buyer relating to the
Goods are confidential and proprietary, and Buyer shall limit distribution
thereof to its trusted employees and strictly prevent disclosure to any
third party.
17. Miscellaneous. (a) Waiver. No failure or delay by Seller in exercising any
right and no course of dealing between Buyer and Seller shall operate as
a waiver of rights by Seller. (b) Assignment. Buyer may not assign its
rights hereunder without Seller's written consent. (c) Law. These Terms
are governed by Illinois law (without regard to conflict of law principles).
Federal and state courts in Illinois shall have exclusive jurisdiction for any
dispute hereunder. (d) Amendment. These Terms constitute the entire
agreement between Buyer and Seller relating to the Goods, and no pro-
vision may be changed or waived unless in writing signed by the parties.
(e) Severability. If any provision hereof is rendered ineffective or invalid,
such provision shall not invalidate any other provision. (f) Setoff. All
claims hereunder by Seller are subject to setoff by Seller for any counter-
claim arising out of any transaction with Buyer. (g) Definitions. As used
herein, "including" means "including without limitation.”

vii
PRECAUTIONS
This section provides general precautions for using the V520 Bar Code Reader.
The information contained in this section is important for the safe and reliable application of the V520 Bar Code
Reader. You must read this section and understand the information contained before attempting to set up or operate
an Bar Code Reader.
1 Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
2 General Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
3 Application Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

viii
Intended Audience 1
1 Intended Audience
This manual is intended for the following personnel, who must also have
knowledge of electrical systems (an electrical engineer or the equivalent).
• Personnel in charge of installing automation systems.
• Personnel in charge of designing automation systems.
• Personnel in charge of managing automation systems and facilities.
2 General Precautions
The user must operate the V520 Bar Code Reader according to the
performance specifications described in the operation manuals.
Please use particular care before using the V520 Bar Code Reader under
conditions which are not described in the manual or applying the V520 Bar
Code Reader to nuclear control systems, railroad systems, aviation systems,
vehicles, combustion systems, medical equipment, amusement machines,
safety equipment, and other systems, machines, and equipment that may
have a serious influence on lives and property if used improperly.
Make sure that the ratings and performance characteristics of the V520 Bar
Code Reader are sufficient for the systems, machines, and equipment, and be
sure to provide the systems, machines, and equipment with double safety
mechanisms.
This manual provides information for installing and operating OMRON V520
Bar Code Readers. Be sure to read this manual before operation and keep
this manual close at hand for reference during operation.
!WARNING It is extremely important that a V520 Bar Code Reader be used for the speci-
fied purpose and under the specified conditions, especially in applications that
can directly or indirectly affect human life.
3 Application Precautions
!WARNING Do not touch the terminals while the power is ON. Doing so may cause an
electric shock.
!WARNING It may be necessary to install a power supply breaker to turn OFF the power
supply before working on the V520 Bar Code Reader. Not turning OFF the
power supply may result in electrical shock.
!WARNING Do not allow metal fragments or lead wire scraps to fall inside the V520 Bar
Code Reader. These may cause electric shock, fire, or malfunction.
!WARNING Do not use the V520 Bar Code Reader in flammable and explosive gas atmo-
spheres. There is danger of explosion.
!WARNING Never disassemble, repair, or modify the V520 Bar Code Reader. Doing so
may cause electric shock, fire or malfunction.

ix
Application Precautions 3
Observe the following precautions when using the V520 Bar Code Reader.
• Use and store the V520 Bar Code Reader within the specified tempera-
ture and humidity ranges. If there is a possibility of the ambient tempera-
ture rising to a temperature above the specified temperature range, take
steps, such as installing fans, to cool the V520 Bar Code Reader. If the
V520 Bar Code Reader is installed incorrectly, heat will build up inside,
shortening the life of the V520 Bar Code Reader. If heat buildup is a prob-
lem, use forced cooling, e.g., install a cooling fan.
• Do not touch the patterns or components on a board with your bare
hands. Hold it by the case.
• To allow heat to escape, do not block the area around the V520 Bar Code
Reader. (Ensure that enough space is left for the heat to escape.) Do not
block the ventilation holes on the casing.
• Use the V520 Bar Code Reader within the specified power supply voltage
and rated load ranges.
• Wire properly using the correct terminal polarity.
• Make sure that the rated voltage is reached within 2 seconds after the
power supply is turned ON.
• Attach a surge suppressor or noise filter to peripheral devices that gener-
ate noise (in particular, motors, transformers, solenoids, magnetic coils or
other equipment that have an inductance component). When mounting a
noise filter on the power supply, be sure to first check the filter's voltage
and current capacity, and then mount the filter as close as possible to the
V520 Bar Code Reader. Allow as much space as possible between the
V520 Bar Code Reader and devices that generate powerful high-fre-
quency noise (e.g., high-frequency welders, high-frequency sewing
machines) or surges.
• To reduce induction noise, separate the high-voltage or large-current
power lines from other lines, and avoid parallel or common wiring with the
power lines when you are wiring to the terminals. We recommend using
separating pipes, ducts, or shielded lines.
• Install a switch or circuit breaker in a location easily accessible to the
operator and label it appropriately.
• Do not use the V520 Bar Code Reader in the following places:
• Places subject to dust or corrosive gases (in particular, sulfide gas and
ammonia gas)
• Places subject to high humidity, condensation or freezing
• Places subject to direct sunlight
• Places subject to vibration and large shocks
• Places subject to splashing liquid or oily atmosphere
• Places directly subject to heat radiated from heating equipment
• Places subject to intense temperature changes
• Cleaning: Do not use paint thinner or the equivalent. Use standard grade
alcohol to clean the V520 Bar Code Reader.

x
Application Precautions 3

1
Table of Contents
Section 1: Introduction and Getting
Started
Product Overview ............................................. 3
Quick Start-Up Procedure ................................ 3
Section 2: Technical Specifications
Physical Specifications ......................................5
Symbologies Supported ................................... 5
Optical Specifications ....................................... 5
Pitch.................................................................. 6
Skew ................................................................. 6
Tilt (rotation) ..................................................... 6
Curvature.......................................................... 7
Electrical Specifications.................................... 7
RS-232C Communications Specifications........ 7
Connector Pin-Outs .......................................... 8
Environmental Specifications ........................... 8
Ordering Information......................................... 8
Section 3: Positioning the Scanner
Achieving Optimum Performance ..................... 9
Measuring Scanner Performance ................... 11
The Read Rate Test........................................ 12
Tips for Achieving High Throughput ................13
Tips for Insuring Highest Data Integrity ...........13
Tips for Verifying the Presence
of a Bar Code ..................................................14
Section 4: Configuring the Scanner
Configuring the Scanner ................................. 15
Default Settings............................................... 15
Section 5: Application Engineering
Support
Technical Assistance and Support.................. 17
Common Causes of Poor Performance .......... 17
Modified and/or Customized Scanners........... 17
Section 6: Scanner Servicing and
Maintenance.............................................. 19
Appendix A: Programming Menus &
Commands ................................................ 21
Appendix B: Dimensional
Drawings .................................................... 59
Appendix C: Optical Performance
Charts .......................................................... 61
Appendix D: PLC Connection/
Touchscreen Examples ........................ 63

2
Organization of this Manual
This manual provides the necessary instructions for installing and using the Omron V520-LHA7127 Miniature
High Speed CCD Fixed Position Scanner. The manual is organized as follows:
Section 1: Introduction and Getting Started
Describes the general operation of the V520-LHA7127 scanner. Also provides a Quick Start-Up Procedure that
allows you to begin using the scanner immediately.
Section 2: Technical Specifications
Provides complete specifications, including mechanical details, optical performance, RS-232C
communications and other technical data.
Section 3: Positioning the Scanner for Optimum Performance
Provides detailed instructions and tips for mounting and positioning the scanning to obtain the best scanning
performance. Application Notes describe guidelines for maximizing specific characteristics.
Section 4: Configuring the Scanner
Describes how various parameters can be programmed to customize the scanner for your specific application.
Section 5: Application Engineering Support
Discusses the most common questions and concerns when adapting the V520-LHA7127 scanner in your
application.
Section 6: Scanner Servicing and Maintenance
Discusses the V520-LHA7127 scanner warranty, maintenance and cleaning procedures.
Appendices: Detailed Supporting Information

3
Section 1 - Introduction and Getting Started V520-LHA7127
Section 1
Introduction and Getting Started
Product Overview
V520-LHA7127 Series Fixed Position Scanners are miniature, 700 scans per second, bar code readers
designed to be easily incorporated into host equipment. CCD Scanning technology features 100% solid state
design with absolutely no moving parts. Durability and reliability are assured.
Advanced 32-bit microprocessor technology coupled with Omron’s proven decoding algorithms result in high
speed operation with superior accuracy. The scanners are fully programmable allowing the user to customize
parameters including changing communication settings, selecting symbologies, adding prefixes and appending
suffixes. Programmable settings can be downloaded from the host CPU or computer directly to the scanner.
The series V520-LHA7127 scanners are encased in compact, rugged steel enclosures. The compact size
permits installation in the tightest areas. Scanners are available in both front and side view configurations
allowing great flexibility in mounting and positioning the scanner for optimum performance.
Quick Start-Up Procedure
This section is for those who wish to start using the scanner before reading the complete manual. In only a few
steps the scanner will be operable.
Turn off the power to your PC and connect the scanner to an RS-232C communications port.
Note You must provide +5 Volt DC power to the scanner. This can be accomplished
using the power supply and patch cable available from Omron. If the power
supply is obtained from another source verify that it is identified with the CE
mark. Turn on the power to the PC.
1. Using communications software (e.g., Procom), set the communication parameters: 9600 baud, 1 Start/
Stop Bit, 8 Data Bits, No Parity, No Handshaking, No Flow Control.
2. If you are operating in a Microsoft Windows 3.1 environment, skip to Step 5.
3. If you are operating in a Microsoft Windows 95/98 environment, you can set the communication parame-
ters using Hyper Terminal as follows:
• Open Hyper Terminal. This can be done from Start>Programs>Accessories/Communications.
• Select Hypertrm.exe to create a New Connection.
• In the Connection Description dialog screen enter a name for the new file. If desired, select an Icon. Click
OK.
• In the Connect To (Phone Number) dialog screen, in the box entitled: Connect using select the
communication port, for example, “Direct to Com 1”. Click OK.
•IntheCom 1 Properties screen, enter the appropriate Port Settings: Bit per second = 9600, Data bits = 8,
Parity = None, Stop Character = 1, Handshaking = None, Click OK.
• The hyper-terminal folder you just created will open. From the File pull-down menu, select Properties then
click on the Setting tab.
•IntheProperties Settings dialog screen, Select Terminal keys for the Function, arrow and control key; then
select ANSI for Emulation; the Back scroll buffer line can remain at the default 500.
• Click on the ASCII Setup button. In the ASCII Setup screen, select Echo typed locally so that any keyboard
commands you input will appear on your screen. Click OK. This returns you to the Properties Setting. Click
OK.
4. Your PC and the scanner should now communicate. Skip to Step 6.

4
Section 1 - Introduction and Getting Started V520-LHA7127
5. In a Microsoft Windows 3.1 environment, set the communication parameters using the Terminal function of
Windows.
a) From Window’s Program Manager Main Menu, select Te r m i n a l .
b) From the Te r m i n a l menu, select Settings.
c) From the Settings menu, select Terminal Emulation.
d) Set the emulation to TTY (generic).
e) From the Settings menu, select Terminal Preferences and select the following Terminal modes:
• Line Wrap
• Local Echo
• Sound
• CR/LF: Inbound, Outbound
• Columns: 80
f) From the Settings menu, select Communications, select the COM port, and communication parameters
as shown in Step 2, including no flow control.
6. To verify that the scanner and the PC are communicating properly, send the following command from your
PC keyboard to activate the scanner’s buzzer.
Send the command: <Escape> V5 <Carriage Return>
Note Be sure to use capital letters, e.g. “V5”, not “v5”. The buzzer should sound,
indicating that good communications have been established.
7. A red scanning light should be visible. If it is not visible, the scanner may be in a mode that requires a
“Trigger” Command from the PC to activate it. You can exit that mode by sending the following command
from your PC keyboard:
<Escape> S7 <Carriage Return>
8. The “Trigger” mode will now be deactivated and the red scanner light will be continuously illuminated.
This Quick Start-Up procedure will get you started. However, to best understand the full capabilities of this
scanner, you should read the complete manual.

5
Section 2 - Technical Specifications V520-LHA7127
Section 2
Technical Specifications
Physical Specifications
Case Material Steel (black)
Dimensions Side View)FrontView
(LxHxW) 52 x 20 x 55 mm 47 x 20 x 55 mm
(1.85 x 0.78 x 2.2 in) (1.95 x 0.78 x 2.2 in)
Weight 100 g (3.5 ounces) without cable
Cable length 6.5 feet (2000 mm)
Connector 2.8 m (6 ft) with DB25 pin female connector
Mounting 4 threaded (M-3) mounting holes (2 on each side)
(not to extend more than 3 mm into the case)
Symbologies Supported
• Codabar (NW-7)
• Code 39
• Code 93
• Code 128
• Industrial 2 of 5
• Interleaved 2 of 5
• MSI / Plessey
• WPC (UPC / EAN / JAN)
•IATA
Optical Specifications
Scan rate 700 scans per second ±10%
Wavelength of LED Illumination 660 nanometers
Read Sensor CCD linear array
Focal Distance Side View Front View
(nominal) 1.2 inches from window 1.4 inches from window
Narrow Bar Resolution 5.0 mil at 0.9 PCS
Minimum PCS 0.45 (min. backround reflectance of 70%)

6
Section 2 - Technical Specifications V520-LHA7127
Pitch
Note Recommended operation at 10° ≤ α1, α2 ≤ 15°. Avoid specular reflection
dead zone (hatched).
Skew
Tilt (Rotation)
α1
α2
α1
α2
Front View Side View
Hatched no
read specular
zone ±10˚
Height
of barcode
20˚
OK
OK
10˚
10˚
20˚
30˚
30˚
Height
of barcode
Hatched no
read specular
zone ±13˚
OK
OK
13˚
15˚
15˚ 10˚
10˚
25˚
25˚
Front View Side View
ββ
β= 0 to 6˚
(h = 35.4 mm, α2 = 10˚, θ = 0˚, R = ∞)
β= 0 to 6˚
(h = 31.4 mm, α2 = 10˚, θ = 0˚, R = ∞)
β
β
Side View Front View
θ
θ
θ
θ
θ = 0 to 10˚
(h = 31.4 mm, α2= 10˚, β= 0˚, R = ∞)
θ = 0 to 10˚
(h = 35.4 mm, α2= 10˚, β= 0˚, R = ∞)

7
Section 2 - Technical Specifications V520-LHA7127
Curvature
Electrical Specifications
Operating Voltage +5 VDC ± 5%
Current:
• Operating 158 mA typical; 220 mA max.
• Static 150 mA max.
• Surge 3 A max.
RS-232C Communications Specifications
RS-232C Data Transmission Format
RS-232C Transmit / Receive Character Format
RS-232C Data Format
RS-232C Signal Level
h
R
JAN 13: R = 30 mm (1.2 in.) or
JAN 8: R = 20 mm (0.8 in.) or
Where: PCS 0.9, h = 35.4
α2 = 10˚, β = 0˚, θ = 0˚
Parameter Default Optional Settings
Timing Asynchronous --
No. of start bits 1 bit --
No. of stop bits 1 bit 1 or 2 bits
No. of data bits 8 bits 7 or 8 bits
Parity None Odd/Even/None
Baud Rate 9600 Baud 300 to 38,400 Baud
Handshaking None Hardware/Software/None
TXD/
RXD
Start
Bit LSB
7 or 8
Data Bits MSB
Parity
Bit
Stop
Bit
Transmit Decoded Data CR
Receive ESC Command CR
STX Command ETX
Signal Name In/Out Mark/Off Space/On
TXD
RXD
Out
In
-5 to -15
-3 to -15
+5 to +15
+3 to +15

8
Section 2 - Technical Specifications V520-LHA7127
Connector Pin-outs
9 pin Male Mini-Din Connector “-C” Units
9 pin Female Connector “-P” Units
Environmental Specifications
Temperature
Operating 0° to +40°C (+32° to +104°F)
Storage -10° to +60°C (+14° to +140°F)
Humidity (non-condensing)
Operating 20% to 80%
Storage 20% to 90%
Ambient Light Fluorescent or incandescent: below 5 kilolux
Ordering Information
Pin No. Signal Direction
1- -
2TXDOutput
3RXDInput
4DSR-
5 Signal ground -
6DTR-
7 SRTS Output
8CTSInput
9- -
Pin No. Signal Direction
1- -
2 RXD Input
3 TXD Output
4 RTS Connected to 5
5 CTS Connected to 4
6 +5V Input
7- -
8- -
9 Signal ground -
Part No. Model
V520-LHA7127-C Single line CCD, computer
V520-LHA7127-P Single line CCD, Omron PLC/touch screen

9
Section 3 - Positioning the Scanner V520-LHA7127
Section 3
Positioning the Scanner
Achieving Optimum Performance
Three items greatly impact performance:
• Distance (from the scan window) to the bar code
• Spectral reflection
• Quality of Bar Code labels
1) Distance to the Bar Code
The operation of the scanner is similar to a camera. If you photograph an object that is out of focus, the
resulting picture will be blurry. The same is true with the scanner. If the bar code label is out of focus, the
scanner may have difficulty decoding what appears to be fuzzy bars and spaces.
Focal Distance
Ideally, the distance from the window of the scanner to the bar code label should be equal to the focal distance
of the scanner. For the V520-LHA7127 series fixed position scanners, the nominal focal distance is:
Front view 1.4 in. (35 mm)

10
Section 3 - Positioning the Scanner V520-LHA7127
Depth-of-Field
Just as with a camera, the scanner has a depth-of-field. It can read bar codes that are not precisely at the focal
distance - maybe a little closer, or a little farther away. However, if the bar code label is positioned too far from
the focal distance, the scanner may not be able to successfully decode it.
The depth-of-field varies based on the density of the bar code, i.e., the thickness of the bars. Very high density
bar codes (which have very narrow bars) are readable over a much shorter distance range than low density bar
codes with larger bars.
The following table shows the “typical” depth-of-field (closest to farthest reading distances) for the
V520-LHA7127 series scanners. The actual performance may differ slightly from unit to unit. Also, it is
important to note that this data was measured under ideal conditions using high quality bar code labels. In a
“real world” environment the conditions will not be as ideal. Therefore, the best practice is to position the scan-
ner at its focal distance rather than at the extremes of its depth-of-field.
Typical Reading Distance from Window
(Depth of Field)
Readable Bar Code Width
(Field-of-View)
The table above shows the field-of-view at various distances from the window. The field-of-view is the
maximum width that the scanner is capable of reading. A bar code label postioned anywhere within this field-
of-view can be decoded. The field-of-view is also a measure of the widest bar code label that can be read.
Remember: the width of a bar code label includes not only the bars and spaces but also the required white
space (quiet zone) on each end.
Good design policy is to position the scanner at its focal distance and at the center of the field-of-view. Do not
position it near the extremes of the reading range.
Density of Bar Code Near Distance Far Distance
15 mil 0.6 in. 2.3 in.
10 mil 0.8 in. 2.2 in.
6 mil 1.1 in. 1.8 in.
4 mil 1.3 in. 1.65 in.
Distance from Window Max. Width
0.5 in. 2.0 in.
1.0 in. 2.7 in.
1.5 in. 3.4 in.
2.0 in. 3.9 in.
2.5 in. 4.5 in.

11
Section 3 - Positioning the Scanner V520-LHA7127
2) Avoiding Specular Reflection
Do not position the scanner at an angle that causes the LED illumination to be reflected directly back into the
scanner. This is called specular reflection. Too much reflected light can “blind” the scanner preventing a good
decode.
If the bar code label is located on a flat surface, specular reflectivity occurs between 0 to 10 degrees off
perpendicular (See diagram). If the bar code label is located on a cylindrical surface, such as a test tube, the
angle of specular reflection is measured tangent to the curve. If the curved surface is also moving, there may
be more than one position causing specular reflection. The following diagram indicates the area to avoid:
3) Quality Bar Code Labels
The quality of the bar code label can affect the scanning performance. Poor quality labels are more difficult to
decode and may result in non-reads or potential misreads. The bar code label should be printed to
specifications. This means that the bars are printed within spec, with the correct widths, no ink spread, crisp
edges and no voids. There should be a sufficient quiet zone on both ends of the bar code label. For best
results, the paper or label stock should have a matte finish to diffuse light. The print contrast signal (which is a
comparison of the reflectance of the bars and the background stock) should be as high as practical.
Measuring Scanner Performance
Two methods are helpful in determining the optimum position of the scanner. The first method is to program the
scanner for Trigger Disable and Continuous Read modes. The scanner will always be on and will
continuously read the same bar code. Since the buzzer sounds each time the bar code is read, the sound of
the buzzer can be used like a “Geiger counter.” As the position of the scanner changes the sound of the buzzer
will change. The buzzer sound will be loudest and most continuous at the best reading positions.
Front View
Hatched no
read specular
zone ±10˚
Height
of barcode