Rockwell Automation 2755-DM9, 2755-DM9E User Manual

Bulletin 2755 High Speed Decoder

(Catalog Numbers 2755-DM9 & -DM9E)

User Manual

ALLEN-BRADLEY

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. VAX is registered trademark of Digital Equipment Corporation.

A–B

Using This Chapter

Description of Hardware

Chapter 1

Chapter Objectives 1–1 Overview of This Manual 1–1 Intended Audience 1–2 Conventions Used 1–2 Warnings and Cautions 1–3

Nomenclature 1–3

Related Publications 1–3

Chapter 2

Chapter Objectives 2–1 Differences Between DM9 and DM9E 2–1 Features of the Decoder 2–1 Laser Scan Heads 2–2 Physical Description 2–2 Indicators 2–3 Communications Ports 2–5 Output Modules 2–6 Power and Scan Head Connectors 2–8 Accessories 2–9

How the Decoder Operates

Configuring Your Decoder

Chapter 3

Chapter Objectives 3–1 How the Decoder Operates 3–1 Communications 3–4 RAM and EEPROM Memory 3–7 Operating Modes 3–9 Trigger Ending Conditions 3–10 Response Modes 3–10

Chapter 4

Chapter Objectives 4–1 Initial Programming of the Decoder 4–1 Programming Terminal Cable 4–2 Menu and Setup Screens 4–2 Start–up Procedure 4–4 Select Operation Menu 4–5 Using and Editing the Configuration (Setup) Screens 4–11 Command Bar 4–15

Table of Contents

Configuring Your Decoder

Installing the Decoder

Chapter 4

Setup Screen #1 4–17 Setup Screen #1 Fields 4–20

Message Format 4–20 Data Check Characters 4–23 Host Communications 4–24

Package Detect Input 4–27 Setup Screen #2 4–28 Setup Screen #2 Fields 4–31

Bar Code Types 4–31

Code Lengths 4–31

Scanner Control 4–33

Match Code Table 4–40

Outputs 4–41

Input 4–43 Programming Example 4–45

Chapter 5

Chapter Objectives 5–1 Equipment You Will Need 5–1 Electrical Precautions 5–2 How to Handle Excessive Noise 5–2 Grounding Recommendations 5–3 Determining Space Requirements 5–3 Installing the Decoder 5–4 How to Connect Your Equipment 5–5 Installing and Wiring Modules 5–7

Communicating With a Host

Chapter 6

Chapter Objectives 6–1 Host Port 6–1 RS–232 Interface 6–2 RS–422 Interface 6–4 RS–485 Interface 6–5 Message Format 6–7 Example Data Messages 6–9 Host Commands 6–10

Table of Contents

Host Commands Using a RS-232 or RS-422 Interface

Chapter 7

Chapter Objectives 7–1 RS–232/RS–422 ASCII Command Protocol 7–1

Single Character Commands 7–1 Two Character Commands 7–2 Responses to Commands 7–3 Host Commands 7–4

1. Set Code 39, I 2–of–5, and Codabar Check Characters 7–5

2. Clear Output Counter 7–6

3. Enable/Disable Bar Code Type 7–6

4. Set Configuration to Default Values 7–7

5. Set Host Communications 7–7

6. Write Header Message 7–8

7. Set Package Detect Input Filter and Sense 7–9

8. Write Source Identification Message 7–10

9. Read Output Counter 7–10

10. Set Message Format 7–11

11. Read Match Code Table 7–12

12. Write Match Code Table 7–13

13. Clear No–Read Count 7–14

14. Write No–Read Message 7–15

15. Read No–Read Count 7–16

16. Set Output Condition and Duration 7–16

17. Clear Package Count 7–17

18. Read Package Count 7–17

19. Reset Decoder 7–18

20. Set Configuration to Default Values, Save to EEPROM & Restart 7–18

21. Save New Configuration to EEPROM and Restart 7–19

22. Save New Configuration to EEPROM (No Restart) 7–19

23. Set Scanner Control 7–20

24. Set Bar Code Specific Length 7–21

Host Commands Using the RS-485 Interface

Chapter 8

Chapter Objectives 8–1 RS–485 Command Protocols 8–1 RS–485 ASCII Command Protocol 8–1 RS–485 PCCC Command Protocol 8–2

PCCC Command Format 8–2 PCCC Commands 8–5

Unprotected Read Command 8–5

Unprotected Read Command Structure 8–6 Unprotected Read Reply Format 8–7 Unprotected Read Example 8–9

iii

Table of Contents

Unprotected Write Command 8–10

Unprotected Write Command Structure 8–10

Unprotected Write Command Cont.

Unprotected Write Reply Format 8–12

Writing to the Command Area of Memory 8–13 Communication Link Diagnostic Commands 8–16

Link Diagnostic Command Structure 8–16

Diagnostic Link Reply Format 8–17

Read Diagnostic Counters Reply 8–18

Read Diagnostic Status Reply 8–19

Diagnostic Loop Reply 8–21

Reset Counters Reply 8–21

Maintenance and Troubleshooting

Specificatuions

Setting Up the Programming Terminal

Default Parameters Of the Decoder

ASCII Conversion Table

Configuration Area of Memory

Chapter 9

Chapter Objectives 9–1 Maintaining the Decoder 9–1 Power Input Fuse Replacement 9–1 Module Fuse Replacement 9–2 Troubleshooting 9–3

Chapter 10

Decoder 10–1

Appendix A A–1

Appendix B B–1

Appendix C C–1

Appendix D D–1

Protocol Selection Chart

Transmission Check Codes

Appendix E E–1

Appendix F F–1

Glossary G–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Index I–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents

Figures

2.1 Catalog No. 2755–DM9, –DM9E Decoder 2–3. . . . . . . . . . . . . . . . . . . .

2.2 LED Indicators 2–4. . .

2.3 Communications Ports 2–5. . .

2.4 Output Modules 2–6. . .

2.5 Input power and Scan Head Connectors 2–8. . .

3.1 Catalog No. 2755–DM9, –DM9E Decoder 3–1. . .

3.2 DC Output Module Application 3–3. . .

3.3 AC Output Module Application 3–3. . .

3.4 Input Module Auto Load Application 3–4. . .

3.5 Communications Interface Examples 3–5. . .

3.6 Decoder Memory 3–8. . .

4.1 Setup Screen #1 4–17. .

4.2 Setup Screen #2 4–28. .

4.3 Package Detect Signal 4–34. .

4.4 Internal Timer Trigger 4–35. .

4.5 Setting Inter–Scan Timer 4–39. .

4.6 Auto Load Feature 4–44. .

5.1 Mounting Dimensions of the Decoder 5–3. . .

5.2 Fasteners Used to Mount the Decoder 5–4. . .

5.3 Connecting Equipment to the Decoder’s Ports 5–5. . .

5.4 Modules and Connectors 5–7. . .

5.5 Module Connections 5–8. . .

6.1 Host Port Pin Numbers 6–2. . .

6.2 Communications With RS–232 Host Device 6–4. . .

6.3 Communications With RS–422 Host Device 6–5. . .

6.4 Communications In an RS–485 Network 6–6. . .

6.5 Message Format 6–7. . .

9.1 Power Input Fuse 9–1. . .

9.2 Output Module Fuse 9–2. . .

A.1 Connections for Cable Used With an ADM 3E Terminal A–1. . . A.2 Connections for Cable Used With DEC–VT100 Terminal A–2. . . A.3 One Possible Setup for DEC–VT100 Terminal A–2. . . A.4 Connections for Cable Used With 1784–T45 Terminal A–3. . . A.5 Connections for Cable Used With a Televideo 955 Terminal A–4. . A.6 Connections for Cable Used With 1770–T1, –T2, or –T3 Terminals A–5

Chapter

Chapter Objectives

Overview of this Manual

A–B

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.

• Conventions useed.

• Warnings and cautions.

This manual describes how to use the Catalog No. 2755–DM9 and DM9E High Speed Decoders. This manual contains the following chapters:

Chapter Title Purpose

1 Using This Manual

2 Description of the Hardware

3 How the Decoder Operates

4 Configuring Your Decoder

5 Installing the Decoder

6 Communicating With a Host

10 Specifications

- Appendices Includes glossary of terms.

- Index Alphabetical index.

Host Commands Using the RS-232 or RS-422 Interface

Host Commands Using the RS–485 Interface

Maintenance and Troubleshooting

Provides an overview of the manual.

Describes features and design of the decoder.

Describes how the decoder operates.

Provides step-by-step instructions on how to configure the decoder.

Provides general rules and recommendations for installing the decoder.

Describes how a host device can communicate with a decoder.

Describes how to send host commands and receive data using the RS-232 and RS-422 interfaces.

Describes how to send commands and receive data on an RS-485 Local Area Network.

Describes basic troubleshooting and fuse replacement procedures.

Provides basic decoder specifications.

1–1

Chapter 1

Using this Manual

Intended Audience

Conventions Used

You do not require any special knowledge to read this manual and follow its instructions. If the decoder will be used to communicate with a computer or

PLC communication devices, communications standards (RS–232, RS–422, RS–485), and communications terminology. In this manual, we describe the commands that a host device can transmit to the decoder and the command responses sent by the decoder. We do not describe how to create PLC or computer programs for generating the commands.

Some chapters in this manual contain examples of how to enter data or commands. The following conventions are used:

programmable controller, we assume you are familiar with

• A symbol or word in brackets represents a single key you would press.

These include keys such as [RETURN], [SHIFT] or [A].

• Punctuation, such as commas, and symbols such as “/” would be entered

as shown.

• ASCII codes are represented by either their mnemonic (CR, ETX, LF,

etc.) or their decimal number equivalent (CR =13, S=83, etc.). Refer to Appendix C for a listing of the ASCII codes.

Note: When the [RETURN] key is specified, this is the carriage return function of your keyboard. This key may also be labeled ENTER or use some other symbol.

1–2

We have included numerous examples of CRT displays. All CRT displays are shown inside a box with a double lined border. We have reproduced these screens as accurately as possible. However, due to legibility and space requirements we have modified some of the spacing.

When describing the programming terminal used to configure the decoder, we make reference to arrow keys. If you use an Allen–Bradley Industrial Terminal (Catalog No. 1770–T1, –T2, or –T3), you do not have arrow keys. Use the [CTRL] and [U], [D], [L], or [R] keys for the U

ight cursor functions, respectively.

p, Down, Left, or

Chapter 1

Using this Manual

Warnings And Cautions

Nomenclature

Related Publications

Description Title Purpose of Publication

Catalog Number

2755-ND002②

Both warnings and cautions are found in this manual and on the equipment. The following symbols are used:

WARNING: A warning symbol means people might be injured if the procedures are not followed.

CAUTION: A caution symbol is used when machinery could be damaged if the procedures are not followed.

This manual may contain some terms that you are not familiar with. We have provided a glossary of terms at the back of this manual (Appendix G) to assist you.

The following table lists related publications that you may require to install and operate the decoder.

User’s Manual for Bulletin 2755 Industrial Medium and High Speed Bar Code Scanners.

Provides information on the Catalog Number 2755-L7 and -L9 scan heads①.

Publication 2755-829②

Publication 2755-826②

Publication 2755-801②

Publication 2760-812

Publication 2760-822

Publication 2760-823

Publication

1771-6.5.34

Publication

1771-6.5.15

Publication

1771-6.5.13

① We have provided only a partial catalog number since there are various configurations available for these scan heads. ② Additional scan heads may be available for use with the Catalog Number 2755-DM9 decoder. Refer to your Allen-Bradley representative for more information.

User’s Manual for Bulletin 2755 Enhanced Medium Speed Scan Heads

User’s Manual for Bulletin 2755 Medium Speed Material Handling Scanners

User’s Manual for Bulletin 2755 Modular Bar Code Scanners

User’s Manual for Bulletin 2760–RB Flexible Interface Module

Protocol Cartridge Programming Manual Provides instruction on using the RS-232/RS-422

Protocol Cartridge Programming Manual Provides instruction on using the RS-485

BASIC Module User’s Manual Provides information on the Catalog Number

User’s Manual for 1771–KE and 1771–KF Provides information on the Catalog Number

ASCII I/O Module User’s Manual Provides information on the Catalog Number

Provides information on the Catalog Number 2755-L4F and -L4R enhanced scan heads①.

Provides information on the Catalog Number 2755-L4F and -L4R scan heads①.

Provides information on the Catalog Number 2755-L4 and -L5 scan heads①.

Provides information on the Catalog Number 2760-RB Flexible Interface Module.

protocol cartridge for the 2760-RB module.

1771-DB BASIC module.

1771-KE and -KF Communications Controllers.

1771-DA ASCII I/O module.

1–3

Chapter

Chapter Objectives

Differences between Catalog Number 2755-DM9 & 2755-DM9E

A–B

Description of Hardware

This chapter provides an overview of the Catalog Number 2755-DM9,

-DM9E Bar Code Decoder. We also provide descriptions of the major features.

Note: In this chapter and in subsequent chapters, we will refer to the Catalog Number 2755-DM9, -DM9E High Speed Decoder as the decoder.

• Catalog Number 2755-DM9 decoder includes a 120 VAC power cord, and

an English language manual. An LED label in English is attached to the decoder.

Features

• Catalog Number 2755-DM9E decoder includes an unterminated 220 VAC

line cord and information for ordering User’s Manuals in English and other languages. LED labels in English, French, German, Italian, and Spanish are packaged with the decoder. Operation of the 2755-DM9 and DM9E decoders is identical.

The decoder acquires video data from a separate laser scan head and then decodes this data. The decoder can then:

• Send the decoded data to another device such as a host computer,

auxiliary terminal, or programmable controller.

• Compare the decoded data to previously stored data and use the results of

this comparison to operate up to eight discrete outputs (match code operation).

Note: The decoder also maintains counters for package count, no-reads, and discrete outputs.

The decoder is capable of decoding the following types of bar code symbols:

• Code 39. • UPC-A and E

• Interleaved 2 of 5. • EAN-8 and 13

• Codabar. • Code 128.

2–1

Chapter 2

Description of Hardware

You can program many of the operating parameters of the decoder. This programming capability allows you to adapt the decoder to a specific application. You can:

• Specify decoder operating modes.

• Select types and lengths of symbols to be read.

• Select communications protocols used when communicating with a

computer or programmable controller.

• Enter up to eight match codes.

• Specify up to eight discrete outputs.

You can select continuous scanning or you can define what event will trigger the label reading process. You can specify the trigger to be:

• A signal from the package detector connected to the laser scan head.

• A command received from a host computer.

• The decoder’s internal timer.

The decoder can communicate with a host computer using the following standards:

Laser Scan Heads

Physical Description

• RS-232.

• RS-422.

• RS-485 (Multi-drop Network using Allen-Bradley DH485 protocol).

The decoder will operate with the following scan heads:

• Catalog No. 2755-L7 and -L9 Medium and High Speed, Industrial Bar

Code Scanners.

• Catalog No. 2755-L4F, -L4R, and -L5R Medium Speed, Enhanced,

Material Handling Scanners.

Note: We have not listed complete catalog numbers for the scan heads. These scan heads are available in a variety of configurations.

Figure 2.1 shows the decoder. The decoder is housed in a steel enclosure (NEMA 1 rating). The decoder enclosure is 14” wide, 2.81” tall, and 10.75” deep (refer to Chapter 5 for installation drawing). On top of the decoder are fourteen indicator LEDs which indicate the status of the decoder and the outputs (refer to Indicator Section in this chapter). On the back of the decoder are the communications ports (refer to Communications Port Section in this chapter). A separate removable cover allows for easy access to the discrete output modules and fuses (refer to Output Module Section in this chapter). Connectors are also provided for the laser scan head and power line connector cables.

2–2

(Continued)

Figure 2.1 Catalog Number 2755-DM9, -DM9E

Chapter 2

Description of Hardware

Indicators

90-061-1

Fourteen LED indicators (Figure 2.2) provide an indication of the decoder status. The indicators provide the following indications:

• POWER - This green indicator illuminates when power is applied to the

decoder.

• LASER ON - This red indicator illuminates when the decoder has enabled

the scan head to turn on the laser light source. The LED may illuminate even if the scan head is disconnected or the “Laser On” switch for the Catalog No. 2755-L7 or -L9 scan heads is in the OFF position.

• TRIGGER ACTIVE - This yellow indicator illuminates when the decoder

is in the triggered mode and scanning has been triggered by:

1. The package detector connected to the scan head.

2. A Start Scan command sent by the host.

3. The internal timer.

The LED remains on until a trigger OFF command is received.

• VALID READ - This green indicator illuminates momentarily whenever

the decoder has met the fields per scan and capture count parameters.

2–3

Chapter 2

Description of Hardware

Note: This LED may not correspond to a read output condition (refer to page 4-41). In the triggered mode, the read output condition must meet the fields per package parameter.

• CPU ACTIVE - This green indicator is continuously illuminated under

normal operation. Failure of the CPU ACTIVE indicator to illuminate is an indication of a hardware failure.

• COMMUNICATIONS - This yellow indicator illuminates momentarily

whenever data is sent to or received at either of the communications ports.

• OUTPUTS 1 through 8- Each of these red indicators indicate the status

of the output modules. When an output module is turned on, the respective indicator illuminates.

Note: If you have a Catalog No. 2755-DM9 decoder, the LED label is attached. If you have a Catalog No. 2755-DM9E decoder, the LED label is not attached. Apply the appropriate language label supplied with the decoder.

Figure 2.2 LED Indicators

2–4

90-061-5

Chapter 2

Description of Hardware

Communications Ports

There are two communication port connectors on the decoder:

• HOST port connector. The HOST port connector supports RS-232,

RS-422, and RS-485 communication interfaces. Through this port, you can link the decoder to a host computer or programmable controller. Both commands and data may be sent to/from the host device.

Note: The RS-485 interface allows the decoder to be installed as part of a multi-drop network. Refer to Chapter 3 for a more detailed description.

• AUX port connector. The AUX or auxiliary port connector allows you to

program and monitor the decoder using one of the following CRTs: Allen-Bradley Industrial Data Terminal (Catalog No. 1770-T1, -T2, and

-T3), Allen-Bradley T45 Laptop Terminal (Catalog No. 1784-T45), Digital VT100, Televideo 955, Lear Siegler ADM 3E, or a terminal/computer that emulates one of the terminals listed.

Figure 2.3 Communication Ports

90-061-2

2–5

Chapter 2

Description of Hardware

Output Modules

Two DC output modules (Catalog No. 1781-OB5S) are provided with the decoder. You can add up to six more AC or DC output modules for a total of eight. Module location #8 can also accept an input module for auto loading match codes (refer to Chapters 3 and 4). All output module types can be installed in any of the eight module slots. You can program the decoder to turn on these output modules based upon the conditions you specify during configuration of the decoder. Use these outputs to operate electromechanical devices such as relays, alarms, etc. Fuses protect the decoder from power overloads.

Figure 2.4 Output Modules

2–6

90-061-4

Chapter 2

Description of Hardware

The following output modules are available.

Note: Output modules function as a switch, not as a power source.

Catalog No. 1781-0B5S 1781-0A5S 1781-OM5S

Nominal Line Voltage

-- 120 VAC 240 VAC

Maximum Line Voltage

Minimum Line Voltage 3.0 VDC 12 VAC 24 VAC Maximum Peak Off State Voltage 60 VDC

Maximum Off-State Leakage

Static off-state dv/dt -- 200 V/ usec 200 V/ usec

Maximum On-State Current

Minimum On-State Current 10 mA DC 50 mA RMS 50 mA RMS

Maximum 1 Cycle Surge -- 4.0 A Peak 4.0 A Peak

Maximum 1 Second Surge

Peak On-State Voltage 1.5 V DC

60 VDC 140 VAC 280 VAC

400 V Peak 600 V Peak

1.0 mA 2.5 mA RMS 4.0 mA RMS

0.5 A DC 0.5 A RMS 0.5 A RMS

1.5 A DC -- --

1.6 V Peak 1.6 V Peak

The following input modules are available (for position No. 8 only). See Chapters 3 and 4.

Note: The input modules require a voltage source for activation.

Catalog No. 1781-IB5S 1781-IA5S 1781-IM5S

Maximum Input Voltage 32 VDC 140V RMS/AC 280 V RMS/AC Minimum Input Voltage

Input Resistance 1k ohm - Maximum Input Current 32mA DC @

Drop Out Current

Allowable Off State Input Current 1.0 mA DC 3.0 mA RMS 2.0 mA RMS Allowable Off State Input V oltage

3.3 VDC 90V RMS/AC 180 V RMS/AC

10mA RMS @

32 VDC

1.0 mA DC 2.5 mA RMS 1.5 mA RMS

2.0 VDC 50 VRMS/AC 120 VRMS/AC

140 VRMS

8mA RMS @

280 VRMS

Note: Note polarity when connecting DC Input and Output modules.

2–7

Chapter 2

Description of Hardware

Power and Scan Head Connectors

The decoder will accept line voltages from 85 to 264 volts AC at a frequency of 47 to 63 Hz without any adjustments. The Catalog No. 2755-DM9 decoder is supplied with a 120VAC rated power cord. If you are powering a 2755-DM9 decoder with a supply voltage greater than 120 VAC, you must obtain a suitable power cord.

Note: Catalog No. 2755-DM9E is supplied with an unterminated power cord. Attach a suitable connector using the diagram provided in Chapter 5.

A 15 pin D connector is provided on the decoder for connecting the laser scan head. You can connect the decoder to the scan head using one of the following:

• For Catalog No. 2755-L7 and -L9 scan heads use-

10 foot (3.05 meter) cable (Catalog No. 2755-CL10) 25 foot (7.62 meter) cable (Catalog No. 2755-CL25)

• For Catalog No. 2755-L4 and -L5 scan heads use-

10 foot (3.05 meter) cable (Catalog No. 2755-CK10) 25 foot (7.62 meter) cable (Catalog No. 2755-CK25)

Note: The scan head is powered by the decoder through the cable. The scan heads do not require a separate power source.

Figure 2.5 Input Power and Scan Head Connectors

90-061-4

2–8

Chapter 2

Description of Hardware

Accessories

The following table lists the accessories that you may require for use with the decoder.

Catalog Number Item Description

Raster and side scanning devices that operate at 350 scans per second. Raster scanners scan both vertical and horizontal directions

2755-L7①

2755-L9①

2755-L4F①

-L4R①

2755-L5R①

1781-OB5S DC Output Module 3 to 60 VDC output at 0.5 amperes. 1781-OA5S AC Output Module 12 to 140 VAC output at 0.5 amperes. 1781-OM5S AC Output Module 24 to 280 VAC output at 0.5 amperes. 1781-IB5S DC Input Module 3.3 to 32 VDC 1781-IA5S AC Input Module 90 to 140 VRMS/VDC 1781-IM5S AC Input Module 180 to 280 VRMS/VDC 2760-A485 RS-485 Connector Use these connectors to create cables for an RS-485 network. 2755-CL10 10-ft (3.05 meters) Scan Head Cable 2755-CL25 25-ft (7.62 meters) Scan Head Cable 2755-CK10 10-ft (3.05 meters) Scan Head Cable 2755-CK25 25-ft (7.62 meters) Scan Head Cable

W77104-899-01 Purchased

Locally Package

Detector Assembly

User Created Host Port Communications Cable For connecting host device to the decoder, refer to Chapter 6. User Created Auxiliary Port Communications Cable

W77121-801-01 W77121-801-02

Industrial Medium Speed Bar Code Scanner

Industrial High Speed Bar Code Scanner

Enhanced Medium Speed Scanner

Enhanced Medium Speed Raster Scanner

Replacement Fuse- Power Output Modules

Replacement Fuse- Line Input Power 250V ( 1 amp, slow blow), 5 x 20 mm or 3AG 2755-NP3

2755-NP5 2755-NP1 2755-NP4

Power Cords -

120 V AC 220 V AC- Unterminated one end

simultaneously. Some of these scan heads have a maximum read distance of 50” (1.27 meters) depending upon symbol size and quality. Scanners can read Case Code symbols (symbols directly printed on kraft paper/cardboard boxes).

Raster and side scanning devices that operate at 800 scans per second. Raster scanners scan both vertical and horizontal directions simultaneously. Some of these scan heads have a maximum read distance of 30” (76 cm) depending upon symbol size and quality .

Front or side scanners that operate at 200 scans per second. Some of these scan heads have a maximum read distance of 50” (1.27 meter) depending upon symbol size and quality . Scanners can read Case Code symbols (symbols directly printed on kraft paper/cardboard boxes).

Raster scanners that operate at 200 scans per second. This scan head has a maximum read distance of 45” (1.14 meters) depending upon symbol size and quality . Scan head scans both vertical and horizontal directions simultaneously. Scanner can read Case Code symbols (symbols directly printed on kraft paper/cardboard boxes).

Use to connect decoder to Catalog No. 2755-L7 or -L9 scan head.① Use to connect decoder to Catalog No. 2755-L7 or -L9 scan head.① Use to connect decoder to Catalog No. 2755-L4 or -L5 scan head.① Use to connect decoder to Catalog No. 2755-L4 or -L5 scan head.①

Plug-in type fuses provide overload protection for the decoder.

Optional, for 2755-L7, -L9 Scan Heads Optional, for 2755-L7, -L9 Scan Heads Optional, for 2755-L4, -L5 Scan Heads Optional, for 2755-L4, -L5 Scan Heads

For connecting programming terminal to the decoder. Refer to Appendix A.

Replacement power cord. User must provide suitable connector.

① We have not provided the complete catalog number since these heads are available in a variety of configurations.

2–9

Chapter

Chapter Objectives

How the Decoder Operates

A–B

How the Decoder Operates

This chapter provides a brief description of how the decoder operates. We also provide a brief description of how the decoder communicates with host devices.

Figure 3.1 is a block diagram of the decoder.

Figure 3.1 Catalog Number 2755-DM9 Decoder

DECODER

DATA

ACQUISITION

POWER SUPPLY - An internal power supply provides power for both the laser scan head and internal circuitry of the decoder. As stated earlier, the source voltage may range from 85 to 264 volts AC. The power supply will automatically adjust to the input voltage.

MICROPROCESSOR

POWER SUPPLY

I/O

LASER SCAN HEAD

DATA ACQUISITION CIRCUIT - The data acquisition circuitry of the decoder receives both video and synchronization signals from the laser scan head. The data acquisition circuitry filters and stores blocks of data received from the scan head in the Random Access Memory (RAM) of the decoder.

3–1

Chapter 3

How the Decoder Operates

MICROPROCESSOR - The microprocessor reads the information obtained by the data acquisition circuit, processes the information, and then makes decisions on what to do with the decoded data based upon your programming instructions.

I/O - A single 25 pin connector (HOST PORT) provides three different interfaces (RS-232, RS-422, and RS-485) for communications with a host computer or programmable controller. The I/O section of the decoder supports asynchronous data transmission at baud rates of up to 38,400 bits per second.

Another 25 pin connector (AUX PORT) provides an RS-232 interface for programming and monitoring of the decoder using a programming terminal. Refer to Chapter 2 for a listing of the terminals that can be used for programming or monitoring.

Up to eight modules can be plugged into the circuit board of the decoder. Refer to Chapter 2 for a description of the input and output modules that can be used. Output modules function as switches, not as power sources (refer to Figures 3.2 and 3.3).

Note: Outputs are initially turned off (open) when power is first applied to the decoder and when the decoder is turned off.

DC Output Module Application

Figure 3.2 illustrates a typical DC output module application. When using high impedance loads, you may have to add an additional resistor (Rx) in parallel with the load. Select a value for Rx that maintains a minimum current of 10 mA through the output module in the on state. Typical values for Rx range from 300 to 6,000 ohms depending upon the source voltage.

Figure 3.2 DC Output Module Application

DECODER

DC SOURCE 3-60 VDC

LOAD

DC OUTPUT MODULE

CONNECTOR BLOCK

FUSE

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Chapter 3

How the Decoder Operates

AC Output Module Application

Figure 3.3 illustrates a typical AC output module application. When using high impedance loads, you may have to add an additional resistor (Rx) in parallel with the load. Select a value for Rx that maintains a minimum current of 50 mA RMS through the output module in the on state.

Figure 3.3 AC Output Module Application

DECODER

AC SOURCE

LOAD

AC OUTPUT MODULE

CONNECTOR BLOCK

FUSE

Input Module Auto Load Application

Figure 3.4 illustrates the auto load input module application.

Figure 3.4

Typical Input Module Auto Load Application

DECODER

Auto Load

CONNECTOR BLOCK

INPUT MODULE AC or DC

MODULE LOCATION #8 ONLY

FUSE

Pushbutton

Communications

AC or DC SOURCE

As stated earlier the decoder can transmit decoded bar code information to a host computer or programmable controller. The three communications

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Chapter 3

How the Decoder Operates

interfaces (RS-232, RS-422, and RS-485) provide a variety of ways to accomplish communications with a host. Figure 3.5 illustrates some of the possible host interfaces.

Note: You can also use the decoder as a stand-alone device using the discrete outputs for control.

Figure 3.5 Communications Interface Examples

PLC

1771 I/O Rack

2760-RB

2760-SFC2

2755-DM9

Decoder

2755-DM9

Decoder

PLC TO DECODER USING A FLEXIBLE INTERFACE MODULE (RS-485)

2755-DM9

Decoder

2755-DM9

Decoder

2755-DM9

Decoder

PLC

PLC TO DECODER USING A FLEXIBLE INTERFACE MODULE (RS-232, RS-422)

• • • • • •

2755-DM9

Decoder

2755-DM9

Decoder

2755-DM9

Decoder

3–4

2755-DM9

Decoder

2755-DM9

Decoder

1771 I/O Rack

2760-RB

2760-SFC1

RS-232 or RS-422

2755-DM9

Decoder

Catalog No. 2760-RB is a Flexible Interface Catalog No. 2760-SFC1, -SFC2 are Protocol Cartridges

Chapter 3

How the Decoder Operates

Figure 3.5 Communications Interface Examples (Continued)

PLC TO DECODER USING AN ASCII MODULE

PLC

1771 I/O Rack

1771-DA

RS-232

2755-DM9

Decoder

COMPUTER TO DECODER

Host Computer

RS-232 or RS-422

2755-DM9

Decoder

PLC TO DECODER USING A BASIC MODULE

PLC

1771 I/O Rack

1771-DB

RS-232

2755-DM9

Decoder

Catalog No. 1771-DB is a BASIC I/O Module Catalog No. 1771-DA is an ASCII I/O Module

ALLEN-BRADLEY LOCAL-AREA NETWORK - Using the Catalog No. 2760-RB Flexible Interface Module with the 2760-SFC2 protocol cartridge and the DM9 in the RS-485 mode, you can multi-drop up to 31 devices on each port of the 2760-RB module.

PROGRAMMABLE CONTROLLERS - You can connect the decoder to a programmable logic controller in one of three ways:

• Through the Allen-Bradley Data Highway.

• Through a Flexible Interface Module (Catalog No. 2760-RB). This

module can be used to create an RS-485 Local Area Network or point-to-point communications using the RS-232 or RS-422 communications interfaces.

• Directly, using a Catalog No. 1771-DB BASIC module or 1771-DA

ASCII I/O module.

HOST COMPUTERS- In most cases, you can directly connect your host computer to the decoder using the RS-232 or RS-422 interface. The decoder can also communicate with an industrial computer through the Allen-Bradley Data Highway.

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How the Decoder Operates

RAM and EEPROM Memory

Before you try to change the operating configuration of the decoder, you should understand how configuration parameters are stored. The decoder has two types of memory:

• EEPROM- Electrically Erasable Programmable Read Only Memory

contains the “non-volatile” operating configuration of the decoder. The term “non-volatile” means that the memory is not lost when you turn the power off or restart the decoder.

• RAM- Random Access Memory contains the current operating

configuration of the decoder. Any changes made to the the operating configuration of the decoder are made to the decoder’s RAM. All information stored in the RAM is erased when the power to the decoder is turned off. When the decoder is turned back on (rebooted), the configuration parameters are copied from non-volatile memory (EEPROM) to the RAM.

Figure 3.6 illustrates the relationship between the RAM and EEPROM memory. Notice that the user interface is with the RAM memory. Also, notice that the decoder transfers the contents of the RAM to the EEPROM during a SAVE operation and copies the same contents from the EEPROM to RAM during startup.

Note: The configuration in RAM determines the decoder performance (operating characteristics).

Figure 3.6 Decoder Memory

3–6

Decoder

Performance

User Interface

RECALL START-UP

RESTART

RAM

EEPROM

SAVE

DEFAULT

Default

Configuration

Settings

-Programmer

-Host

When you change the operating configuration of the decoder, you are changing the configuration stored in the decoder’s RAM. Since the decoder takes its current operating instructions from RAM, any changes you make

Chapter 3

How the Decoder Operates

will become effective immediately (except for host communications parameters listed below). If you want to enter changes into the decoder’s permanent memory (EEPROM), you must use the SAVE command. When the decoder is restarted, the operating parameters of the EEPROM are transferred into RAM. If you don’t transfer the contents of the RAM to the EEPROM (SAVE function), any changes made to the operating configuration stored in RAM will be erased when the power is turned off.

Note: Unlike the other decoder operating parameters, changes to the following parameters will not take effect until you SAVE the changes and then restart the decoder.

• HOST PROTOCOL

• DEVICE ADDRESS

• ACK and NAK CHARACTERS①

Operating Modes

• BAUD RATE

• NUMBER OF DATA & STOP BITS

• PARITY

① Changes to ACK NAK characters will take effect immediately if you are in the ACK/NAK mode.

The decoder also stores the original factory set operating parameters in EPROM. This type of memory cannot be changed by the user, and is always available in case of a programming error. When you use a DEFAULT command (described in next chapter), the decoder transfers the factory set default parameters to the RAM. Once installed in RAM, the default parameters control the operation of the decoder. If you want to save the default parameters into the EEPROM, you must use the SAVE command.

A RECALL command (described in next chapter) transfers the previously SAVED configuration from the EEPROM to the decoder’s RAM. Once installed into RAM, the recalled configuration is displayed and controls operation of the decoder.

When you configure the operation of the decoder, you will be required to provide a variety of operating parameters. You should have an understanding of the decoder’s operating modes prior to configuring the decoder (Chapter

4). The decoder operates in one of two modes:

• Continuous mode - In this mode, the decoder will continuously attempt to

decode data. Use this mode for initial scan head adjustments and positioning.

• Triggered mode - In this mode, the decoder will only attempt to decode

data after receiving a trigger.

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In the triggered mode of operation, there are three possible trigger sources:

• Host command - The command is generated by a host computer or

programmable controller.

• Package detect - A package detector connected to the scan head is the

source for the trigger.

• Internal timer - The internal timer cycles the trigger from on to off based

on a timed interval.

Trigger Ending Coditions

Response Modes

When a trigger on is received, the decoder will continuously attempt to decode bar codes until one of the following trigger ending conditions occurs:

(a) The number of fields (bar codes) per package count is satisfied. (b) A trigger off command is sent by a host device. (c) Package detect signal is no longer present. (d) The internal timer (No-Read timer) times out.

In the triggered mode of operation there are two options which determine when the decoder will send bar code information to a host and/or operate discrete outputs:

• After Valid Package - A valid package is a package that has valid bar

code symbols and meets the fields (bar codes) per package count (condition

(a) listed above).

• End of Trigger - Refer to trigger ending conditions (b, c, d) listed above.

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Chapter

Chapter Objectives

Initial Programming of the Decoder

A–B

Configuring Your Decoder

Because the decoder can be used many ways, you will need to configure the decoder to meet the requirements of your application. To do this, you must make some decisions. We will show you how to use the menus and setup screens that appear on a programming terminal to select the options you need.

You must configure the decoder to meet the requirements of the application. You can configure the decoder either before or after installation. If you

change the configuration while a triggered decode is in progress, there is the possibility of missing a package and/or losing data.

Note: The default parameters for the decoder are given in Appendix B. If

these settings meet your requirements, you will not have to program the decoder.

You will need the following equipment:

1. Decoder with power cable.

2. One of the following programming terminals:

• Allen-Bradley Industrial Terminal (Catalog No.1770-T1, -T2, or -T3).

• Allen-Bradley T45 Laptop Terminal (Catalog No. 1784-T45).

• Lear Siegler 3E.

• Televideo 955.

• DEC VT-100.

• A terminal or personal computer that accurately emulates one of the

above.

3. A cable to connect your programming terminal to the decoder. Note: Prior to configuring your decoder, we suggest that you review the

description of how the decoder stores configuration data (refer to Chapter 3, RAM and EEPROM Memory descriptions).

Note: Refer to Appendix A for programming terminal setup. The programming terminal you use must be configured with the following parameters: Number of data bits: 8 Number of stop bits: 1 Baud rate: 9600 Parity: None Flow Control: XON / XOFF

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Configuring Y our Decoder

Programming Terminal Cable

Menus and Setup Screens

Programming of the decoder is done through the AUX connector on the back of the decoder. female, D type connector. Depending upon your programming terminal, most standard RS-232 communications cables will work. If you need to create a communications cable, refer to Appendix A.

You can program and/or monitor the operation of the decoder using the following CRT screens:

The AUX port connector on the decoder is a standard 25 pin,

• Select Language Screen - Use this screen to select English, French,

German, Italian, or Spanish language screens.

• CRT Select Menu - You use this menu to select the type of programming

terminal being used.

• Select operation Menu - Using this menu, you select one of six

operations:

1) Display Labels Screen- Displays bar code labels as they are decoded.

2) System Status Screen- Displays the status of the decoder.

3) Setup Screens Setup Screen 1- Use this screen to configure the host interface which

includes host message format, host communications parameters and protocol, and filtering of the package detect input.

Start-up Procedure

4–2

Setup Screen 2- Use this screen to configure the decoder for the bar

code symbologies, bar code lengths, scan head operation, match code settings, and configuration of output modules.

4) Reset Status and Counters

5) Restart System

6) Select Language Screen- This screen allows you to reselect one of the following languages:

• English

• French

• German

• Italian

• Spanish

After you have connected the programming terminal to the decoder and attached the power cord:

Step 1 - Turn ON the programming terminal and configure the terminal for communications with the decoder. Appendix A provides information on setting up the programming terminal.

Chapter 4

Configuring Y our Decoder

Step 2 - Turn the decoder ON. The green LEDs, labeled POWER ON and CPU ACTIVE, will light.

Step 3 - When the following screen appears, press the key that corresponds to the language you are using. All of the remaining screens will appear in the selected language.

SELECT LANGUAGE CHOIX DU LANGAGE WAEHLE SPRACHE

1) English 1) Anglais 1) Englisch

2) French 2) Francais 2) Franzoesisch

3) German 3) Allemand 3) Deutsch

4) Italian 4) Italien 4) Italienisch

5) Spanish 5) Espagnol 5) Spanisch

Press 1, 2, 3, 4, 5, or ESC Appuyer 1, 2, 3, 4, 5 ou ESC Drueck

e 1, 2, 3, 4, 5, oder ESC

SELEZIONARE LINGUA SELECCIONAR LENGUA

1) Inglese 1) Ingles

2) Francese 2) Frances

3) Tedesco 3) Aleman

4) Italiano 4) Italiano

5) Spangnolo 5) Castellano

Premere 1, 2, 3, 4, 5 o ESC Pulsar 1, 2, 3, 4, 5, o ESC

Step 4 - After selecting the language, the decoder will display the CRT select screen. Press the key (1, 2, 3, 4, or 5) that corresponds to the terminal you are using. Pressing the [ESC] key, will return you to the language selection screen.

SELECT CRT TYPE

1 - Allen-Bradley 1770 Industrial Terminal 2 - Allen-Bradley T45 Portable Terminal 3 - Lear Siegler ADM 3E 4 - Televideo 955 5 - Digital VT100

Press 1, 2, 3, 4, 5 or ESC

Step 5 - After selecting the CRT type, the decoder will display the select operation menu. The remaining displays that you will see depends upon the operation that you select.

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