PSC LM520 Integration & Programming Manual

R44-2016 (Rev. E)

LM520 Scanner

Integration & Programming Manual

R44-2016 i-1

Contents

The LM520 Bar Code Scanner

Overview .........................................................................................................................................................1

Unpacking the LM520................................................................................................................................ .... . 2

Scanner Care .................................................................................................................................................2

Mounting the LM520

General Considerations ..................................................................................................................................3

Mounting .........................................................................................................................................................3

Mounting the Scanner Stand-Alone............ ..... ..................................... ..... ..... ................................. ..... .... ..... . 4

Integrating the Scanner to Read at the Proper Distance ................................................................................4

Integrating the Scanner Behind a Window .....................................................................................................5

Electrical Interface ..........................................................................................................................................8

Interface Cable Schematic................................................................................................................. ..... . 9

LM520 Scanner Configuration

Configuration Management ..........................................................................................................................10

Programming Methods......................................................................... ..... ..... .............................................. 12

Programming through the Serial Interface .............................................................................................12

Programming with Bar Codes................................................................................................................ 13

Conventions ..................................................................................................................................................13

Setting Serial Communication Parameters................................................................................................... 14

Baud Rate ..............................................................................................................................................14

Data Format........................................................................................................................................... 15

Flow Control........................................................................................................................................... 16

Controlling Scanning Through Host Commands.......................................................................................... 17

Triggering Scanning Using Software Switch ..........................................................................................17

Triggering Scanning Using Hardware Switch ........................................................................................ 18

Continuous Scanning Mode ...................................................................................................................18

LaserSense Scanning Mode.................................................................................................................. 19

Canceling Software Triggered Scanning ...............................................................................................19

Setting Symbology Parameters.................................................................................................................... 20

Enabling All Symbologies ......................................................................................................................20

EAN ........................................................................................................................................................21

UPC .......................................................................................................................................................21

Code 128................................... ..... ..... ..... ..................................... ..... ..... ..... ......................................... 22

Code ISBT 128.................................... ..... .... ..... ...................................... ..... .... ..... ................................ 23

Code 93..................................... ..... ..... ..... ..................................... ..... ..... ..... ......................................... 25

Codabar .................................................................................................................................................25

Code 39 ......................................... ..... ..... ..................................... ..... ..... ..... ..........................................26

Interleaved 2 of 5................................................................................................................................... 27

Standard 2 of 5...................................................................................................................................... 28

Formatting Bar Code Data............................................................................................................................ 29

Preamble ................................................................................................................................................29

Postamble ..............................................................................................................................................29

Filters..................................................................................................................................................... 30

Field Descriptions ............................................................................................................................31

Pad Character ................ ...................................... .... ..... ..... ...................................... .... ...................33

Edit Function ...................................................................................................................................33

R44-2016 i-2

Setting the Bar Code Format................................................................................................................. 34

Additional Commands........................... ..... ..... .... ...................................... ..... ..... .... ..................................... 35

Good Read Beeper Duration .................................................................................................................35

Laser Timeout ........................................................................................................................................35

Double Read Timeout............................................................................................................................ 36

Read Verification ...................................... .... ..... ...................................... ..... .... ..... .................................36

No Read Message................. .... ..... ...................................... ..... .... ..... ................................................... 37

No Read Output Signal ..........................................................................................................................37

No Read Output Signal Mode 1 ......................................................................................................37

No Read Output Signal Mode 2 ......................................................................................................37

Diagnostic Commands ...........................................................................................................................38

Good Read LED Duration ......................................................................................................................38

Appendix A:Technical Specifications ......................................................... ..................................................A-1

Appendix B: Mechanical Specifications .......................................................................................................B-1

Appendix C: Factory Default Configuration .................................................................................................C-1

Appendix D: LM520 Programming Labels ....................................................................................................D-1

Appendix E: ASCII Conversion Table ...........................................................................................................E-1

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List of Tables

Table 1. Electrical Interface Specifications ..........................................................................................8

Table 2. Configuration Commands .....................................................................................................10

Table 3. Baud Rate ..............................................................................................................................14

Table 4. Data Format ..........................................................................................................................15

Table 5. Flow Control .........................................................................................................................16

Table 6. Software Switch Control .......................................................................................................17

Table 7. Hardware Switch Control .....................................................................................................18

Table 8. Continuous Scanning Mode ..................................................................................................18

Table 9. LaserSense Mode ..................................................................................................................19

Table 10. Symbologies .......................................................................................................................20

Table 11. EAN ....................................................................................................................................21

Table 12. UPC .....................................................................................................................................21

Table 13. Code 128 .............................................................................................................................22

Table 14. ISBT Symbology ................................................................................................................23

Table 15. Concatenation Pairs ............................................................................................................24

Table 16. ISBT Commands ................................................................................................................24

Table 17. Code 93 ...............................................................................................................................25

Table 18. Codabar ...............................................................................................................................25

Table 19. Code 39 ...............................................................................................................................26

Table 20. Interleaved 2 of 5 ................................................................................................................27

Table 21. Standard 2 of 5 ....................................................................................................................28

Table 22. Preamble .............................................................................................................................29

Table 23. Postamble ............................................................................................................................29

Table 24. Filter Examples ...................................................................................................................30

Table 25. Symbology Identifiers ........................................................................................................32

Table 26. Pad Characters ....................................................................................................................33

Table 27. Edit Functions .....................................................................................................................33

Table 28. Bar Code Format .................................................................................................................34

Table 29. Beeper Duration ..................................................................................................................35

Table 30. Laser Timeouts ...................................................................................................................35

Table 31. Double Read Timeout .........................................................................................................36

Table 32. Read Verification ................................................................................................................36

Table 33. No Read Message ...............................................................................................................37

Table 34. No Read Output Mode ........................................................................................................38

Table 35. Diagnostic Commands ........................................................................................................38

Table 36. Good Read LED Duration ..................................................................................................38

Table A-1. Performance Specifications ...........................................................................................A-1

Table A-2. Power Requirements ...................................................................................................... A-2

Table A-3. Physical and Environmental Specifications .................................................................. A-2

Table A-4. Agency Approvals ......................................................................................................... A-2

Table C-1. Factory Default Configuration ........................................................................................C-1

Table D-1. Programming Labels .................................................................................................... D-1

Table E-1. ASCII Conversion Table .................................................................................................E-1

R44-2016 1

Section 1

The LM520 Bar Code Scanner

Overview

The LM520 scanner is a compact, decoded, single-line scanner for fixed position or embed­ded applications, such as conveyor, library, document tracking, chemical analyzers, vending
machines, point-of-sale (POS) terminals, and other attended or unattended scanning appli­cations. The LM520 is a complete scanning system, ready to plug in and scan. The LM520
presents a fast, easy and low-cost way to incorporate scanning into any application where
you need to read a bar code.

A typical system using the LM520 scanner consists of the scanner itself and a host system
such as a PC, POS system, or package sorting system. The host system controls the scanner
and receives the decoded bar code data produced by the scanner. The laser in the LM520
scanner emits coherent visible light. When a bar code passes through the scanner’s beam,
light is reflected off the bar code. The scanner collects this reflected light, processes it into a
digital signal and decodes it into data that can be used by the host system. In some cases the
data may be processed further by the scanner before being transmitted to the host.

The LM520 has four different operational modes which can be used to scan a bar code. The
four operational modes include:

• an external switch such as an output line from a Programmable Controller (also

known as a PLC) can be used to enable scanning

• software commands from the host system

• continuous scanning operations, and

• a unique PSC motion detection circuitry called LaserSense™. This circuitry allows

the LM520 to only scan when an object is passed in front of it.

The various modes are selected via host commands or special programming bar codes.

The LM520 Bar Code Scanner Section 1

2 LM520 Scanner Integration & Programming Manual

Unpacking the LM520

The LM520 bar code scan scanner is shipped in custom packaging. Carefully open the
package, and remove the scanner from the packing material.

The LM520 standard configuration includes:

• LM520 scanner

• power supply

• mounting hardware (two bolt studs with nuts)

• interface cable - male DB9 (scanner side) [with optional beeper if ordered]

• diskette with this manual and other information

When you open the shipping cart on, visually inspect the pack age’s contents. If any parts ar e
damaged or you need additional hardware, please contact your reseller or the PSC
Customer Support Center at 1-800-547-2507.

Scanner Care

The LM520 bar code scanner contains sensitive components which require special
handling. PSC Inc. may not warrant damage due to improper handling.

• Do not open the scanner’s case. Doing so will void the warranty.

• Avoid touching the front window. Fingerprints will degrade the scanner’s

performance.

• Only clean the scan window when visual inspection reveals dirt or residue.
Remove lint or foreign material be present with filtered clean air. Remove
fingerprints or other residue using clean, cotton-tipped applicators dipped in
isopropyl alcohol, or with soft tissues dipped in high-quality lens or eyeglass
cleaner. Do not reuse cotton-tipped applicators or tissues.

• Do not scrub the window.

• Never wipe the window with a dry tissue or applicator.

R44-2016 3

Section 2

Mounting the LM520

The LM520 bar code scanner is designed to be mounted to a stand in a fixed position. This
section describes the layout of the mounts for optimum scanner performance.

General Considerations

Although the LM520 bar code scanner has been designed to be impact-resistant, it is impor­tant to consider the effect of the environment on the scanner. In particular, the mounting
scheme should minimize the possibility of foreign objects contacting the window’s surface.
Such contact will damage the window over time and re duce the scann er’s performance. The
mounting design should also take into consideration the clearance needed for the power
supply and interface cables. These cables should be routed away from the operator’s work­ing area in attended applications.

Mounting

System integration is made easy with the LM520’s unique mounting design. Six mounting
grooves in the scanner’s sealed enclosure enable mounting on any one of four sides. When
looking at the back of the scanner, these slots are located as shown in Figure 1.

Figure 1. Mounting

Appendix B, Mechanical Specifications shows mechanical drawings of the precise position of
the mounting slots relative to the scanning laser beam.

6789

12345

Mounting Slots

Mounting Slots

1.00"

(2.54cm)

0.50"

(1.27cm)

0.50"

(1.27cm)

0.675"

(1.71cm)

0.675"

(1.71cm)

LM520 Scanner

Mounting Slots (6 total)

Mounting the LM520 Section 2

4 LM520 Scanner Integration & Programming Manual

Mounting the Scanner Stand-Alone

For most instances using an adjustable mount is recommended. The position of the scan line
can be fine-tuned during actual installation and the scanner’s distance from the scanned
object can be easily changed. The location of the operator should also be considered for
attended applications. Care should be taken to position the scanner to minimize the possi­bility of the operator overturning the scanner, spilling liquid on the scanner, inadvertently
unplugging the cables, and so on.

Integrating the Scanner to Read at the Proper Distance

When deciding how to mount the LM520, there are many criteria that must be considered.
First, there are minimum and maximum distances that the bar code can be from the front of
the scanner to properly read, depending on the size of the bar code. These distances, or
depth of field, are specified in Appendix A, Technical Specifications.

Second, the scanner must be positioned so that the bar code to be read is not “square” or
parallel to the front of the scanner. The scanner must have at least 3 degrees skew angle to
operate properly. See Appendix B, Mechanical Specifications for such information as skew,
pitch, and the scanner’s mechanical parameters.

Third, the scanner must be positioned so that the scan line will be long enough to cover the
entire bar code. The scan line should exceed the width of the bar code since only about 80%
of the scan line is usable (see Figure 2). Use the following formula to calculate the expected
usable line length (l) at a given distance (d):

l = [(d+0.88in) x 2 x tan (q)] x 0.8 (if d is measured in inches)
or
l = [(d+2.34cm) x 2 x tan (q)] x 0.8 (if d is measured in centimeters)

where

l = usable line length
d = distance from the front of scanner
q = half of the scan angle, (23° ± 2.0°)

Section 2 Mounting the LM520

R44-2016 5

Figure 2. Mounting the Scanner

Integrating the Scanner Behind a Window

When the LM520 scanner is integrated into a larger system, additional factors must be taken
into account. The most important of these is an additional window placed between the
LM520 and the bar code to be read. While an additional window provides protection for the
LM520, it will also degrade the scanner’s performance due to the need for the laser light to
traverse two additional optical surfaces passing through to the bar codes, and the reflected
light returning. Following the instructions in this section will help optimize the amount of
outgoing light that reaches the bar code and the amount of reflected light that is collected by
the scanner.

The LM520 scanner emits a laser beam in the form of a scan line. The beam’s light exits the
scanner’s window and reflects off the bar code symbol. The reflected light returns through
the window, and is collected with a photodiode. As in any optical system, any type of win­dow causes a reduction in the amount of light that exits or enters the scanner since some of
the laser light is lost due to surface reflection.

LM520 scanner

l = 80%
of scan line

d

.88"

2.34cm

q=

Mounting the LM520 Section 2

6 LM520 Scanner Integration & Programming Manual

The design and placement of the window is critical for optimum system performance. The
following issues must be considered.

• The window must not block outgoing laser light.

• The window must not block laser light reflected from the bar code.

Figure 2 shows the minimum size and position of the window along the horizon­tal and vertical axes, respectively. The minimum window size must increase as

the distance between the scanner and the window increases. This is necessary
to accommodate the width of the scan line.

• Reflections of outgoing laser light caused by the window or other reflective sur­faces should not reach the front window of the scanner.

Determine the window tilt based on your application. The tilt angle of the window (that is,
its position relative to the optical axis or center-line) is important because a portion of the
emitted light will always be specularly reflected from each of the two window surfaces. This
reflected light must not reach the scanner’s window either directly or via multiple reflec­tions from other parts of the system.

Figure 3. Tilt Angle

Nominal
Beam Path

d = 1.250"

31.74mm

0.880"

22.34mm

Angle = 103.7˚

0.125"

3.18mm

0.820"

20.83mm

Reflected light

Window

Angle

= 90 + 0.5 [ arctan (

)]

= 103.7

0.65

1.25

Section 2 Mounting the LM520

R44-2016 7

An example of acceptable system window inclination is shown in Figure 2. As can be seen,
moving the system wind ow cl oser to the scanne r mak es it n eces sary to incr e ase the win dow
angle with respect to vertical. Less inclination is necessary if the reflection is directed below,
rather than above the scanner, since laser light is emitted near the bottom of the scanner’s
window and collected near the top of the scanner’s window. If the light reflected from the
window will be deflected above the scanner , the required window angle (fr om horizontal) is
given by:

If the light will be deflected below the scanner , the r equired window angle (from horizontal)
is given by:

The window material you select depends on the anticipated environment and your
scanner’s intended use. Appropriate window materials include glass, sapphire, and plastic.
Glass, and especially sapphire, have adequate surface hardness for most applications.
However , if you use any type of plastic, it should have a protective hard-coat on the exposed
surface. The hard-coat will protect the plastic surface from damage if the system window
needs to be cleaned.

In addition to hard-coating, some window applications may require special treatment such
as antistatic or antireflection coatings. In general, do not use antiglare coatings due to
undesirable polarization and diffusion effects.

Angle

= 90 + 0.5 [ arctan (

)]

if d is measured in inches

0.65

d

Angle

= 90 + 0.5 [ arctan (

)]

if d is measured in cm

1.65

d

Angle

= 90 - 0.5 [ arctan (

)]

if d is measured in inches

0.2

d

Angle

= 90 - 0.5 [ arctan (

)]

if d is measured in cm

0.51

d

Mounting the LM520 Section 2

8 LM520 Scanner Integration & Programming Manual

Electrical Interface

The LM520 scanner communicates with the host over a standard DB-9 connector. The
pinouts for the connector are shown in Table 1.

Table 1. Electrical Interface Specifications

Pin #

Direction

(relative to
LM520)

Signal Function

1 Output

Beeper/
Good Read

1

1

Beeper Drive/Good Read source current must be limited to 50mA with a maximum voltage of 5VDC.

5VDC output signal used to drive an audio indicator.

2 Output TX

Serial asynchronous RS232C le vel data transm itted to the host . NRZ f ormat
and user programmable f or wo rd fo rmat and baud rate. (Default: 9600 baud,
8 data bits, no parity, 1 stop bit).

3 Input RX

Serial asynchronous RS232C level data r eceived f r om th e ho st. NRZ format
and user programmable f or wo rd fo rmat and baud rate. (Default: 9600 baud,
8 data bits, no parity, 1 stop bit).

4 Output

No Read

2

2

No Read output will source 15mA @ 5VDC. The maximum sink current must be limited to 200mA with a maximum voltage of 14VDC.

This signal is asserted at the end of a scanning cycle if no label is decoded
and will remain asserted until:

1. A successful decode occurs, or

2. A user specified timeout period elapses.
This may be configured in 100ms increments from 100 ms to 9900 ms
(9.9 seconds). Refer to the section titled No Read Output.
NOTE: If the timeout is used, the signal will be immediately deasserted if a
software scan command, hardware scan trigger on pin 9 or a LaserSense
scan occurs before the user specified tim e elapses. Setting a timeout is not
available in Continuous Scan mode.

5 Input Gnd Power supply/signal ground.
6 Input Vcc Power supply input voltage (4.75 - 12.0VDC)
7 Input CTS RS232C Clear to send control line.
8 Output RTS RS232C Request to send control line.

9 Input

Scan Trigger

3

3

Scan trigger signal must be limited to a maximum input voltage of 5VDC with a maximum input current of 10mA.

Ground on this input initiates bar code scanning. Scanning will continue
until either: (a) this line returns to high (5VDC) level, or (b) this line is dis­connected, or (c) the programmed time period expires, or (d) a bar code is
decoded.

Section 2 Mounting the LM520

R44-2016 9

Interface Cable Schematic

The drawing in Figure 4 shows a schematic view of the electrical connection between the
scanner and the host.

Figure 4. Interface Cable Schematic

ORANGE
YELLOW
VIOLET
GREEN
RED
WHITE
BROWN
BLUE

1
2
3
4
5
6
7
8
9

3
2

7

4
5

1

2

3

DB25-S

DB9-P

HOST END

SCANNER END

Connector is a 2.5 mm stereo plug
for the scan trigger, no read signal
and power supply ground.

Power Supply

4.75 - 12VDC

Beeper
(if applicable)

BEEPER/GOOD READ
TXD
RXD
NO READ
GND
VCC IN
CTS
RTS
TRIGGER_IN

R44-2016 10

Section 3

LM520 Scanner Configuration

The LM520 offers a command interface which allows a wide range of customization. Com­mands can be combined with standard programming bar codes to develop an active config­uration and a saved or factory default configuration.

Configuration Management

The LM520 scanner always contains two configuration sets: the Active configuration and
the Factory Default configuration. Both configurations are stored in nonvolatile memory.
When the scanner receives a command changing the configuration, it changes the Active
configuration. If the scanner is reset to the Factory Default configuration, the factory
defaults are copied to the Active configuration. See Appendix C, Factory Default Configura-
tion for a concise list of the factory defaults.

The LM520 offers the ability to change and save a new Factory Default configuration. To
overwrite the Factory Default configuration as shipped from PSC, first make changes to the
Active Configuration, then store the Active Configuration as the Factory Default. The
previous Factory Default will be overwritten. Figure 5 illustrates this process. Table 2
describes the commands for changing the default configuration.

Table 2. Configuration Commands

Command Setting

Z1

Reset active configuration to factory defaults.

The active configuration will be overwritten.

Z2

Store the active configuration as Factory Default.

The contents of the Factory Default will be overwritten.

Section 3 LM520 Scanner Configuration

R44-2016 11

Figure 5. Configuration Management

Factory Default

Configuration

Host Serial Command

or

Programming Label

Active

Configuration

Z2

Z1

Z1 - Copy vaulted configuration into active configuration.
Z2 - Copy configuration from active configuration to the factory default configuration.