Siemens SIMATIC CP 440 User Manual

Preface, Contents

SIMATIC

Point-to-point Communication
CP 440
Installation and Parameter
Assignment

Manual

Product Description
Basic Principles of Serial Data

Transmission

Commissioning the CP 440

Installing the CP 440
Configuring and

Parameterizing the CP 440
Communication Using Function

Blocks
Start-up Characteristics and

Operating Mode Transitions of
the CP 440

Diagnostics with the CP 440
Programming Example –

Standard Blocks

1
2
3
4
5
6

7
8
9

02/2000
A5E00057742
Edition 02

Appendices

Technical Specifications

Connecting Cables
Communication Matrix of the

Protocols
Accessories and Order

Numbers
Reference for SIMATIC S7

Index

A
B

C
D
E

Safety Guidelines

This manual contains notices which you should observe to ensure your own personal safety, as well as to
protect the product and connected equipment. These notices are highlighted in the manual by a warning
triangle and are marked as follows according to the level of danger:

Danger

!

indicates that death, severe personal injury or substantial property damage will result if proper precau­tions are not taken.

Warning

!

indicates that death, severe personal injury or substantial property damage can result if proper precau­tions are not taken.

Caution

!

indicates that minor personal injury or property damage can result if proper precautions are not taken.

Note

draws your attention to particularly important information on the product, handling the product, or to a
particular part of the documentation.

Qualified Personnel

Only qualified personnel should be allowed to install and work on this equipment. Qualified persons are
defined as persons who are authorized to commission, to ground, and to tag circuits, equipment, and sys­tems in accordance with established safety practices and standards.

Correct Usage

Note the following:

Warning

!

Trademarks

The reproduction, transmission or use of this document or its
contents is not permitted without express written authority.
Offenders will be liable for damages. All rights, including rights
created b y patent grant or registration of a utility model or design, are
reserved.

Siemens AG
Bereich Automatisierungs- und Antriebstechnik
Geschaeftsgebiet Industrie-Automatisierungssysteme
Postfach 4848, D- 90327 Nuernberg

Index-2

Siemens Aktiengesellschaft A5E00057742

This device and its components may only be used for the applications described in the catalog or the
technical descriptions, and only in connection with devices or components from other manufacturers
which have been approved or recommended by Siemens.

This product can only function correctly and safely if it is transported, stored, set up, and installed cor­rectly, and operated and maintained as recommended.

SIMATIC, SIMATIC HMI and SIMATIC NET are registered trademarks of SIEMENS AG.
Some of other designations used in these documents are also registered trademarks; the owner’s rights

may be violated if they are used by third parties for their own purposes.

Disclaimer of LiabilityCopyright { Siemens AG 2000 All rights reserved

We have checked the contents of this manual for agreement with the
hardware and software described. Since deviations cannot be pre­cluded entirely, we cannot guarantee full agreement. However, the
data in this manual are reviewed regularly and any necessary cor­rections included in subsequent editions. Suggestions for improve­ment are welcomed.

 Siemens AG 2000

Point-to-point connection CP 341Installation and Parameter Assignment

Technical data subject to change.

C79000-G7000-C341-02

Preface

Purpose

This manual explains how to establish and operate a point-to-point connection.

Contents of This Manual

The manual describes the hardware and software of the CP 440 communication
processor and its integration in an S7-400 programmable controller. It is divided up
into instruction-based chapters and a reference section (appendices).

The following subjects are covered:

• The basics of point-to-point communication with the CP 440

• Starting up the CP 440

• Installing the CP 440

• Communication with the CP 440

• Troubleshooting

• Application examples

• Properties and technical specifications

Scope of This Manual

This manual is valid for the following:

Product Order Number As of Version

CP 440 with the
X27 RS 422/485 interface

Note

The description of the CP 440 communication processor in this manual were
correct at the time of publication. We reserve the right to describe modifications to
the functionality of the modules in a separate Product Information.

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

6ES7 440-1CS00-0YE0 01

iii

Preface

Structure of This Manual

To help you to quickly find the information you require, this manual offers the
following:

• You will find a full table of contents at the beginning of the manual.

• Finally, a comprehensive index allows quick access to information on specific

subjects.

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Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Other Manuals Required

Appendix E contains a list of the other manuals on the subject of the S7-400 that
you will require in order to put your system into operation.

Electronic Manuals

The entire set of SIMATIC S7 documentation is available on CD-ROM.

Standards, Certificates and Approvals

The CP 440 communication processor meets the requirements and criteria of
IEC 1131, Part 2 and the requirements for CE marking. The CP 440 has CSA
certification, UL recognition and FM approval.

Recycling and Disposal

The CP 440 is an environment-friendly product. It is exceptional for the following:

Preface

• Housing plastic with halogen-free flame protection and is highly resistant to fire

• Laser inscriptions (i.e. no labels)

• Plastics identification in accordance with DIN 54840

• Fewer materials used due to size reduction; fewer parts due to integration in

ASICs

The CP 440 is suitable for recycling on account of the low level of contaminants in
its components.

For further information about environment-friendly recycling and the procedure for
disposing of your old equipment, please contact:

Siemens Aktiengesellschaft
Anlagenbau und Technische Dienstleistungen
ATD TD 3 Kreislaufwirtschaft
Postfach 32 40
D-91050 Erlangen, Germany

Phone: + 49 91 31/7-3 36 98
Fax: + 49 91 31/7-2 66 43

The people there will adapt their advice to suit your situation and provide a
comprehensive and flexible recycling and disposal system at a fixed price. After
disposal you will receive information giving you a breakdown of the relevant
material fractions and the associated documents as evidence of the materials
involved.

Point-to-point connection CP 440 Installation and Parameter Assignment
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v

Preface

Additional Assistance

Please contact your local Siemens representative if you have any queries about
the products described in this manual. A list of Siemens representatives worldwide
is contained, for example, in the “Siemens Worldwide” Appendix of the manual

S7-400 Programmable Controller, Hardware and Installation

If you have any questions or suggestions concerning this manual, please fill out the
form at the back and return it to the specified address. Please feel free to enter
your personal assessment of the manual in the form provided.

We offer a range of courses to help get you started with the SIMATIC S7
programmable controller. Please contact your local training center or the central
training center in Nuremberg, D-90027 Germany (tel. [phone]).

Constantly Updated Information

You can obtain constantly updated information on the SIMATIC products on the
Internet at http://www.ad.siemens.de

.

In addition, SIMATIC Customer Support provides you with up-to-date information
and downloads that can be useful to you when using SIMATIC products:

• On the Internet at http://www.ad.siemens.de/simatic-cs

• Via the SIMATIC Customer Support Mailbox (German) at 49 [phone]

or the SIMATIC Customer Support BBS (English).

The mailbox is best accessed with a modem up to V.34 (28.8 kbps) parameterized
as follows: 8, N, 1, ANSI, or via ISDN (x.75, 64 kbits).

You can contact SIMATIC Customer Support by phone at 49 [phone] or
by fax at 49 [phone]. You can send questions by e-mail on the Internet or
to the above-mentioned mailbox.

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Contents

1 Product Description 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 Applications of the CP 440 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2 Components Required for a Point-to-Point Connection with the CP 440 1-3.

1.3 Design of the CP 440 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.4 Features of the X27 (RS 422/485) Interface 1-8. . . . . . . . . . . . . . . . . . . . . . . . .

1.4.1 Cables for Connecting the CP 440 to a Communication Partner 1-8. . . . . . . .

2 Basic Principles of Serial Data Transmission 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1 Serial Transmission of a Character 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2 Transmission Procedure with a Point-to-Point Connection 2-6. . . . . . . . . . . . .

2.2.1 ISO 7-Layer Reference Model for Data Transmission 2-6. . . . . . . . . . . . . . . . .

2.2.2 Data Transmission with the ASCII Driver 2-11. . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.3 Data Transmission with the 3964(R) Procedure 2-24. . . . . . . . . . . . . . . . . . . . . .

3 Commissioning the CP 440 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.1 Sequence of Steps to Be Taken 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2 Commissioning the Physical Interface 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 Installing the CP 440 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.1 CP 440 Slots 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.2 Installing and Removing the CP 440 4-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.3 Installation Guidelines 4-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 Configuring and Parameterizing the CP 440 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.1 Configuring the CP 440 5-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.2 Parameterizing the Communication Protocols 5-3. . . . . . . . . . . . . . . . . . . . . . .

5.3 Parameterization Data 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.3.1 Basic Parameters of the CP 440 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.3.2 Parameterization Data of the ASCII Driver 5-6. . . . . . . . . . . . . . . . . . . . . . . . . .

5.3.3 Parameterization Data of the 3964(R) Procedure 5-14. . . . . . . . . . . . . . . . . . . .

5.4 Management of the Parameter Data 5-20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.5 Uploading Firmware Updates 5-21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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vii

Contents

6 Communication Using Function Blocks 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.1 Communication Using Function Blocks 6-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.2 Overview of the Function Blocks 6-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.3 Notes on Program Structure 6-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.4 Using the Function Blocks 6-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.4.1 The S7 Transmits Data to a Communication Partner,

10 SEND_440 FB 6-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.4.2 S7 Receives Data from a Communication Partner, 9 RECV_440 FB 6-10. . . .

6.4.3 Deleting the Receive Buffer (11 “RES_RECV” FB) 6-14. . . . . . . . . . . . . . . . . . .

6.5 Programming the Function Blocks 6-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.5.1 General Information on Data Block Assignment 6-18. . . . . . . . . . . . . . . . . . . . .

6.5.2 Supplying the Block Parameters 6-19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.6 General Information on Program Processing 6-23. . . . . . . . . . . . . . . . . . . . . . . .

6.7 Technical Specifications of the Function Blocks 6-24. . . . . . . . . . . . . . . . . . . . . .

7 Startup Characteristics and Operating Mode Transitions of the CP 440 7-1. . . . .

7.1 Operating Modes of the CP 440 7-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.2 Startup Characteristics of the CP 440 7-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.3 Behavior of the CP 440 During Operating Mode Transitions of the CPU 7-3.

7.4 Behavior of the Sender Line Drivers of the Serial Interface

During Particular Operating Modes of the CP 440 7-4. . . . . . . . . . . . . . . . . . . .

8 Diagnostics with the CP 440 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.1 Diagnostic functions of the CP 440 8-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.2 Diagnosis via the Display Elements of the CP 440 8-3. . . . . . . . . . . . . . . . . . .

8.3 Diagnostic Messages of the Function Blocks 8-5. . . . . . . . . . . . . . . . . . . . . . . .

8.4 Diagnostics Using the Diagnostic Buffer of the CP 440 8-14. . . . . . . . . . . . . . .

9 Programming Example – Standard Blocks 9-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.1 General 9-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.2 Device Configuration 9-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.3 Settings 9-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.4 Blocks Used 9-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.5 Installation, Error Messages 9-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.6 Activation, Startup Program and Cyclic Program 9-8. . . . . . . . . . . . . . . . . . . . .

9.6.1 “CP440 SEND RECV” Program Example 9-8. . . . . . . . . . . . . . . . . . . . . . . . . . .

9.6.2 “CP440 1 CYC” Program Example 9-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.6.3 “CP440 ASCII BCC” Program Example 9-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.6.4 “CP440 MASTER” Program Example 9-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.6.5 “CP440 SLAVE” Program Example 9-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Contents

A Technical Specifications A-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A.1 Technical Specifications of the CP 440 A-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A.2 Transmission Times A-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B Connecting Cables B-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B.1 X27 (RS 422/485) Interface of the CP 440 B-2. . . . . . . . . . . . . . . . . . . . . . . . . .

C Communication Matrix of the Protocols C-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

D Accessories and Order Numbers D-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

E Reference for SIMATIC S7 E-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Index Index-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Contents

x

Point-to-point connection CP 440 Installation and Parameter Assignment

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Product Description

In Section You Will Find on Page

1.1 Applications of the CP 440 1-2

1.2 Components Required for a Point-to-Point Connection with the
CP 440

1.3 Design of the CP 440 1-6

1.4 Properties of the X27 (RS 422/485) Interface 1-8

1

1-3

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

1-1

Product Description

1.1 Applications of the CP 440

The CP 440 communication processor enables you to exchange data between
programmable controllers or computers by means of a point-to-point connection.
The CP 440 is designed to transfer short, fast frames.

The following are typically connected to it:

• Scanners, barcode readers

• Sensors

• Weighing scales

Functionality of the CP 440

The CP 440 communication processor provides the following functionality:

• An integrated MPI (Multipoint) X27 (RS422/485) interface

• A maximum transmission length of 200 bytes

• A transmission rate of up to 115.2 kbps, full-duplex

• Integration of the most important transmission protocols in the module firmware

– ASCII driver
– 3964(R) procedure

• Customization of the transmission protocols by means of parameter assignment
with the

CP 440: Point-to-Point Communication, Parameter Assignment

parameterization interface.

Applications of the CP 440

The CP 440 communication processor allows point-to-point communication with
SIMATIC modules and with non-Siemens products. The SIMATIC modules that
can be connected are listed in Appendix C.

Functions Supported by the Interfaces

Table 1-1 Functions of the CP 440

Function

3964(R) procedure Yes No
ASCII driver Yes Yes

• XON/XOFF flow control Yes No

CP 440

RS 422* RS 485*

1-2

* The RS 422 and RS 485 are distinguished by means of parameterization.

Point-to-point connection CP 440 Installation and Parameter Assignment

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Product Description

1.2 Components Required for a Point-to-Point Connection with the CP 440

To establish a point-to-point connection between the CP 440 communication
processor and a communication partner, you require certain hardware and
software components.

Hardware Components

The following table lists the hardware components required for establishing a
point-to-point connection with the CP 440.

Table 1-2 Hardware Components for a Point-to-Point Connection with the CP 440

Components

Rack ... provides the mechanical and

electrical connections of the
S7-400.

Power supply module (PS) ... converts the line voltage

(120/230 VAC or 24 VDC) into
the operating voltage of 24 V and
5 VDC required to supply the
S7-400.

CPU
The CPUs with which the CP 440

cannot be used are listed in
Tables 1-5 and 1-4.

Accessories: Memory card

Backup battery

CP 440 communication
processor

... executes the user program;
communicates via the MPI
interface with other CPUs or with
a programming device.

... communicates via the interface
with one or more communication
partners.

Function Diagram

Standard connecting cable ... connects the CP 440

communication processor to the
communication partner.

Point-to-point connection CP 440 Installation and Parameter Assignment
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1-3

Product Description

Table 1-2 Hardware Components for a Point-to-Point Connection with the CP 440, continued

Components DiagramFunction

Programming device cable ... connects a CPU to a

programming device/PC.

Programming device or PC ... communicates with the CPU of

the S7-400.

Software Components

The following table lists the software components required for establishing a
point-to-point connection with the CP 440.

Table 1-3 Software Components for a Point-to-Point Connection with the CP 440

Components

STEP 7 software package,
as of version 4.0.2

CP 440: Point-to-Point
Communication, Parameter
Assignment

interface, Version 5.1
Function blocks (FBs) with

programming examples

Parameterization

... configures, parameterizes,
programs and tests the S7-400.

... parameterizes the interfaces of
the CP 440.

... control communication
between the CPU and the
CP 440.

Function Diagram

+

License

1-4

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Product Description

CPU Versions

The CP 440 can be operated with all CPU versions except the CPUs listed in the
tables below:

Table 1-4 CPU Versions with Which the CP 440 Can Be Used as of the Version Indicated

CPU MLFB

CPU 412-1 6ES7 412-1XF01-0AB0, Release 5
CPU 413-1 6ES7 413-1XG01-0AB0, Release 5
CPU 413-2 6ES7 413-2XG01-0AB0, Release 5
CPU 414-1 6ES7 414-1XG01-0AB0, Release 5
CPU 414-2 with 128k 6ES7 414-2XG01-0AB0, Release 5
CPU 414-2 with 348k 6ES7 414-2XJ00-0AB0, Release 7
CPU 416-1 6ES7 416-1XJ01-0AB0, Release 5
CPU 416-2 with 0.8 M 6ES7 416-2XK00-0AB0, Release 7
CPU 416-2 with 1.6 M 6ES7 416-2XL00-0AB0, Release 7
CPU 416-2 DP ISA Lite

6ES7 616-2PK00-0AB4, Release 3
CPU 416-2 DP ISA
CPU 412-2 DP PCI
CPU 416-2 DP PCI

Table 1-5 CPU Versions with Which the CP 440 Cannot be Used

CPU MLFB

CPU 412-1 6ES7 412-1XF00-0AB0
CPU 413-1 6ES7 413-1XG00-0AB0
CPU 413-2 6ES7 413-2XG00-0AB0
CPU 414-1 6ES7 414-1XG00-0AB0
CPU 414-2 with 128k 6ES7 414-2XG00-0AB0
CPU 416-1 6ES7 416-1XJ00-0AB0

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1-5

Product Description

1.3 Design of the CP 440

Interface

The CP 440 communication processor is supplied with an integrated serial X27
(RS422/485) interface.

Arrangement of the Controls and Indicators

Fig. 1-1 shows the arrangement of the controls and indicators on the front panel of
the CP 440 communication processor.

CP 440

440 – 1CS00 – 0YE0

V1.0.0

INTF
EXTF

FAULT
TxD
RxD

CP 440

X 2
3 4

Firmware version
INTF

EXTF
FAULT

TxD
RxD

Integrated
X27
(RS422/485)
interface

1-6

Figure 1-1 Arrangement of the Controls and Indicators on the CP 440 Communication

Processor

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

LEDs

Interface

Product Description

The following LEDs are located on the front panel of the CP 440:

• INTF (red) Indicates an internal fault

• EXFT (red) Indicates an external fault

• FAULT (red) Fault LED for interface

• TXD (green) interface sends

• RXD (green) interface receives

The operating modes and faults and errors indicated by these LEDs are described
in Section 8.2. Section 5.5 contains information on the LEDs that come on when
you download firmware updates.

For a detailed description of the interface, see Section 1.4.

Base Connector for the S7 Backplane Bus

On the back panel of the CP 440 you will find the base connector for the S7-400
backplane bus.

The S7-400 backplane bus is the serial data bus via which the CP 440
communicates with the modules of the programmable controller.

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1-7

Product Description

1.4 Features of the X27 (RS 422/485) Interface

Definition

The X27 (RS 422/485) interface is a differential voltage interface used for serial
data transmission in compliance with the X27 standard.

Features

The X27 (RS 422/485) interface has the following features and meets the following
requirements:

• Type: differential voltage interface

• Front connector: 15-pin sub D female with screw fixing

• Max. transmission rate: 115.2 kbps

• Max. cable length: 1200 m at 19200 bps

*

• Standard: DIN 66259 Parts 1 and 3,
EIA-RS 422/485, CCITT V.11

• Degree of protection: IP00

Note

The X27 (RS 422/485) interface can only be run in 4-wire mode with the 3964(R)
protocol.

1.4.1 Cables for Connecting the CP 440 to a Communication Partner

Standard Connecting Cables

For point-to-point connection between the CP 440 and a communication partner,
Siemens offers standard connecting cables in various lengths.

The lengths and order numbers of these cables are listed in Appendix D.

Constructing Your Own Connecting Cables

If you make your own connecting cables, there are some points you must be
aware of. These are described in Appendix B, along with wiring plans and the pin
allocation for the sub D male connector.

* To find out which cable types you can use, see Appendix B.

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Basic Principles of Serial Data Transmission

In Section You Will Find on Page

2.1 Serial Transmission of a Character 2-2

2.2 Transmission Procedure with a Point-to-Point Connection 2-6

2

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2-1

Basic Principles of Serial Data Transmission

2.1 Serial Transmission of a Character

There are various networking alternatives for the transfer of data between two or
more communication partners. The simplest form of data interchange is via a
point-to-point connection between two communication partners.

Point-to-Point Connection

In a point-to-point connection the CP 440 communication processor forms the
interface between a programmable controller and a communication partner. In a
point-to-point connection with the CP 440, the data is transferred serially.

Serial Data Transmission

In serial transmission, the individual bits of each byte of information are transmitted
one after the other in a fixed order.

Drivers for Bidirectional Data Traffic

The CP 440 executes data transfer with communication partners independently via
the serial interface. The CP 440 is equipped with two different drivers for this
purpose.

Bidirectional Data Traffic:

• ASCII driver

• 3964(R) procedure

The CP 440 executes data transfer via the serial interface depending on the
selected driver.

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Bidirectional Data Traffic - Operating Modes

The CP 440 has two operating modes for bidirectional data traffic:

• Half-duplex operation (3964(R) procedure, ASCII driver)
Data is exchanged between the communication partners but only in one

direction at a time. In half-duplex operation, therefore, at any one time, data is
being either sent or received. The exception to this may be individual control
characters for data flow control (e.g. XON/XOFF), which can also be sent while
data is being received or received while data is being sent.

• Full-duplex operation (ASCII driver)
Data is exchanged between two or more communication partners in both

directions simultaneously. In full-duplex operation, therefore, data can be sent
and received at the same time. Each communication partner must be able to
send and receive simultaneously.

Only half-duplex mode can be used with an RS 485 (2-wire) setting.

Basic Principles of Serial Data Transmission

Asynchronous Data Transmission

With the CP 440, serial transmission takes place asynchronously. What is known
as timebase synchronization (a fixed timing code used in the transmission of a
fixed character string) is only upheld during transmission of a character. Each
character to be sent is preceded by a synchronization impulse, or start bit. The end
of the character transmission is signaled by the stop bit.

Declarations

As well as the start and stop bits, further declarations must be made between the
two communication partners before serial transmission can take place. These
include:

• Transmission rate (baud rate)

• Character and acknowledgment delay times

• Parity

• Number of data bits

• Number of stop bits

Section 2.2 describes the importance of the declarations in the various
transmission procedures, and how they are parameterized.

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2-3

Basic Principles of Serial Data Transmission

Character Frames

Data is transmitted between the CP 440 and a communication partner via the
serial interface in a character frame. Two data formats are available for each
character frame. 7 data bits without a parity bit are not supported. You can
parameterize the format for data transmission with the

Communication, Parameter Assignment

By way of example, the figure below shows the two data formats of the 10-bit
character frame.

7 data bits, 1 start bit, 7 data bits, 1 parity bit, 1 stop bit
Signal state “1”

1

Signal state “0”

CP 440: Point-to-Point

parameterization interface.

289

10

1 start bit

8 data bits: 1 start bit, 8 data bits, 1 stop bit
Signal state “1”

1

Signal state “0”

1 start bit

Figure 2-1 10-Bit Character Frame

7 data bits

2 109

8 data bits

1 stop bit

1 parity bit

1 stop bit

2-4

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Character Delay Time

The figure below shows the maximum time permitted between two characters
received within a message frame. This is known as the character delay time.

Signal

1

Basic Principles of Serial Data Transmission

nth character (n + 1)th character

Character delay time

Time t

Figure 2-2 Character Delay Time

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2-5

Basic Principles of Serial Data Transmission

2.2 Transmission Procedure with a Point-to-Point Connection

When data is transmitted, all communication partners involved must follow fixed
rules for handling and implementing the data traffic. The ISO has defined a 7-layer
model, which is recognized as the basis for a worldwide standardization of
transmission protocols for computer-to-computer communication.

2.2.1 ISO 7-Layer Reference Model for Data Transmission

Protocol

All communication partners involved in data transmission must follow fixed rules for
handling and implementing the data traffic. Such rules are called protocols.

A protocol defines the following points:

Procedure

• Operating mode

Half-duplex or full-duplex mode

• Initiative

Which communication partners can initiate data transmission and under what
conditions

• Control characters

Which control characters are to be used for data transmission

• Character frame

Which character frame is to be used for data transmission

• Data backup

The data backup procedure to be used

• Character delay time

The time period within which an incoming character must be received

• Transmission speed

The transmission rate in bps

2-6

This is the specific process according to which the data is transmitted.

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ISO 7-Layer Reference Model

The reference model defines the external behavior of the communication partners.
Each protocol layer, except for the lowest one, is embedded in the next one down.

The individual layers are as follows:

1. Physical layer
– Physical conditions for communication, e.g. transmission medium,

transmission rate

2. Data link layer
– Security procedure for the transmission
– Access modes

3. Network layer
– Network connections
– Definition of the addressing for communication between two partners

4. Transport layer

Basic Principles of Serial Data Transmission

– Error-detection procedure
– Debugging
– Handshaking

5. Session layer
– Establishing communication
– Data exchange management
– Terminating communication

6. Presentation layer
– Conversion of the standard form of data representation of the

communication system into a device-specific form (data interpretation rules)

7. Application layer
– Defining the communication task and the functions it requires

Processing the Protocols

The sending communication partner runs through the protocols from the highest
layer (no. 7 – application layer) to the lowest (no. 1 – physical layer), while the
receiving partner processes the protocols in the reverse order, i.e. starting with
layer 1.

Not all protocols have to take all 7 layers into account. If the sending and receiving
partners both use the same protocol, layer 6 can be omitted.

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2-7

Basic Principles of Serial Data Transmission

Transmission Integrity

Transmission integrity plays an important role in the transmission of data and in
selection of the transmission procedure. Generally speaking, the more layers of the
reference model are applied, the greater the transmission integrity.

Classifying the Supplied Protocols

The CP 440 can handle the following protocols:

• ASCII driver

• 3964(R) procedure

The figure below illustrates how these protocols of the CP 440 fit into the ISO
reference model:

Data link layer

Layer 2

The data bytes are transmitted with

3964(R). Start and stop bits are added;

in the event of an error the transmission

may be repeated.

3964(R)

Layer 1

Figure 2-3 How the Protocols of the CP 440 Fit into the ISO Reference Model

Physical layer

The physical transmission of the

data bytes is defined.

ASCII driver

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Transmission Integrity with the ASCII Driver

Data Integrity When Using the ASCII Driver:

• When data is transmitted by means of the ASCII driver, there are no measures
to ensure data integrity other than the use of a parity bit (which can also be
canceled, depending on how the character frame is set). This means that,
although data transmission with the ASCII driver is very efficient in terms of the
throughput rate, the integrity of the data is not checked.

• Using the parity bit ensures that the inversion of a bit in a character to be
transmitted can be detected. If two or more bits of a character are inverted, this
error can no longer be detected.

• To increase transmission integrity, a checksum and length specification for a
message frame can be employed. These measures must be implemented by
the user.

• A further increase in data integrity can be achieved by means of
acknowledgment message frames in response to send or receive message
frames. This is the case with high-level protocols for data communication (see
ISO 7-layer reference model).

Basic Principles of Serial Data Transmission

Transmission Integrity with 3964

Enhanced Data Integrity with the 3964R Procedure:

• The Hamming distance with the 3964R is 3. This measures the integrity of data
transmission.

• The 3964R procedure ensures high transmission integrity on the data line. This
high integrity is achieved by means of a fixed message-frame setup and
cleardown as well as the use of a block check character (BCC).

Two different procedures for data transmission can be used, either with or without
a block check character:

• Data transmission without a block check character: 3964

• Data transmission with block check character: 3964R

In this manual, the designation 3964(R) is used when descriptions and notes refer
to both data transmission procedures.

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2-9

Basic Principles of Serial Data Transmission

Performance Limits with 3964(R)

Performance Limits of the 3964(R) Procedure:

• Further processing of the send/receive data by the PLC program in the
communication partner is not guaranteed. You can only ensure this by using a
programmable acknowledgment mechanism.

• The block check of the 3964(R) procedure (EXOR logic operation) cannot
detect missing zeros (as a whole character) because a zero in the EXOR logic
operation does not affect the result of the calculation.

Although the loss of an entire character (this character has to be a zero!) is
highly unlikely, it could possibly occur under very bad transmission conditions.

You can protect a transmission against such errors by sending the length of the
data message along with the data itself, and having the length checked at the
other end.

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Basic Principles of Serial Data Transmission

2.2.2 Data Transmission with the ASCII Driver

The ASCII driver controls data transmission via a point-to-point connection
between the CP 440 and a communication partner. This driver contains the
physical layer (layer 1 of the ISO reference model.)

The structure of the message frames is left open through the S7 user passing on
the complete send message frame to the CP 440. For the receive direction, the
end criterion of a message must be parameterized. The structure of the send
message frames may differ from that of the receive message frames.

The ASCII driver allows data of any structure (all printable ASCII characters as
well as all other characters from 00 through FFH (with 8 data bit character frames)
or from 00 through 7FH (with 7 data bit character frames)) to be sent and received.

Both RS422 and RS485 operation are possible.

RS422 Operation

In RS422 operation, the data is transmitted via four cables (four-wire mode). Two
cables (differential signal) are available for the send direction and two for the
receive direction. This means you can send and receive data at the same time
(full-duplex operation).

RS485 Operation

In RS485 operation, the data is transmitted via two cables (two-wire mode). The
two cables (differential signal) are alternately available for the send direction and
the receive direction. This means you can either send or receive data at the same
time (half-duplex operation). After a send operation, the cable is immediately
switched over to receive (the sender becomes high-impedance). The maximum
switchover time is 0.1 ms.

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Basic Principles of Serial Data Transmission

Sending Data with the ASCII Driver

When you send data, you specify the number of user data bytes to be transferred
in the “LEN” parameter of the call of the SEND_440 function block.

When you work with the end criterion “character delay time expired” when
receiving data, the ASCII driver pauses between two message frames when
sending. You can call the SEND_440 FB at any time, but the ASCII driver does not
begin its output until a period longer than the parameterized character delay time
has elapsed since the last message frame was sent.

If you work with the “end-of-text character” criterion, you have a choice of
three options:

• Send up to and including the end-of-text character
The end-of-text character must be included in the data to be sent. Data is sent

only up to and including the end-of-text character, even if the data length
specified in the FB is longer.

• Send up to length parameterized at the FB
Data is sent up to the length parameterized at the FB. The last character must

be the end-of-text character.

• Send up to the length parameterized at the FB and automatically append the
end-of-text character or characters

Data is sent up to the length parameterized at the FB. The end-of-text
character(s) is/are automatically appended; in other words, the end-of-text
characters must not be included in the data to be sent. 1 or 2 characters more
than the number specified by the FB are sent to the partner, depending on the
number of end-of-text characters.

When you work with the end criterion “fixed frame length”, the number of data
bytes transferred in the send direction is as specified for the “LEN” parameter of
the SEND_440 FB. The number of data bytes transferred in the receive direction,
i.e. in the receive DB, is as specified at the receiver using the “fixed message
frame length” parameter in the parameterization interface. The two parameter
settings must be identical, in order to ensure correct data traffic. If an end code is
not detected when data is sent, a pause equal to the length of the monitoring time
is inserted between two message frames to allow the partner to synchronize
(identify the beginning of the message frame).

If some other method of synchronization is used, the pause in sending can be
deactivated by means of the parameterization interface.

2-12

Note

When XON/XOFF flow control is parameterized, the user data must not contain
any of the parameterized XON or XOFF characters. The default settings are DC1
= 11H for XON and DC3 = 13H for XOFF.

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Send data

Basic Principles of Serial Data Transmission

The figure below illustrates a send operation.

Waiting for

send job

Send job arrived

Job processed

Sending user

Figure 2-4 Sequence of a Send Operation

Receiving Data with the ASCII Driver

In data transmission using the ASCII driver, you can choose between three
different end criteria when data is received. The end criterion defines when a
complete message frame is received. The possible end criteria are as follows:

• On Expiry of Character Delay Time

The message frame has neither a fixed length nor a defined end-of-text
character; the end of the message is defined by a pause on the line (expiry of
character delay time).

• On Receipt of One or More End-of-Text Character(s)

data

The amount of data to
be sent is taken from
the LEN parameter of
the send job.

The end of the message frame is marked by one or two defined end-of-text
characters.

• On Receipt of a Fixed Number of Characters

The length of the receive message frames is always identical.

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2-13

Basic Principles of Serial Data Transmission

Code Transparency

The code transparency of the procedure depends on the selection of the
parameterized end criterion and the flow control:

• With one or two end-of-text characters
– Not code-transparent

• When the end criterion is the character delay time or a fixed message frame
length

– Code-transparent

• Code-transparent operation is not possible when XON/XOFF flow control is
used.

Code-transparent means that any character combination can occur in the user
data without the end criterion being detected.

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Basic Principles of Serial Data Transmission

End Criterion: “Expiration of Character Delay Time”

When data is received, the end of the message frame is detected when the
character delay time expires. The received data is accepted from the CPU.

In this case, the character delay time must be set such that it reliably expires
between two consecutive message frames. However, it should be long enough so
that the end of the message frame is not falsely identified whenever the
communication partner takes a send pause within a message frame.

The figure below illustrates a receive operation with the end criterion “expiration of
character delay time”.

Waiting for

character

Character
arrived

Character received

with character

delay time
monitoring

Message frame buffered

Message frame
complete (character
delay time expired)

End criterion for message frame identified, error entry follows

Message frame

entered in receive

buffer

Error when receiving (not a

character delay time error)

Waiting for character
delay time. Received
characters discarded

Error entered in the

ST ATUS output of

the FB.

Figure 2-5 Sequence of Receive Operation with End Criterion “Expiration of Character

Delay Time”

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2-15

Basic Principles of Serial Data Transmission

End Criterion: End-of-Text Character

When data is received, the end of the message frame is detected when the
parameterized end-of-text character(s) arrive. The following options are available:

• One end-of-text character

• Two end-of-text characters, 1st and 2nd end-of-text characters

• Two end-of-text characters, 1st or 2nd end-of-text character

The received data including the end-of-text character(s) is accepted from the CPU.
If the end-of-text character is missing in the received data, the character delay time

elapses during reception and results in a termination of the frame. The character
delay time is used in this instance as the monitoring time. An error message is
issued and the message frame fragment is discarded.

If you are working with end-of-text characters, transmission is not
code-transparent, and you must make sure that the end code(s) is/are not included
in the user data of the user.

Note the following when the last character in the received message frame is not
the end-of-text character.

• End-of-text character elsewhere in the message frame:
All characters including the end-of-text character are entered in the receive DB.

The characters following the end-of-text character:
– Are discarded if the monitoring time expires at the end of the message

frame.

– Are merged with the next message frame if a new message frame is

received before the monitoring time expires.

• End-of-text character not included in message frame:
The message frame:
– Is discarded if the monitoring time expires at the end of the message frame.
– Is merged with the next message frame if a new message frame is received

before the monitoring time expires.

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Basic Principles of Serial Data Transmission

The figure below illustrates a receive operation with the end criterion “end-of-text
character”.

Waiting for

character

Character
arrived

Character received

with end control

and character delay

time

Message frame buffered

Message

frame

complete

End criterion for message frame identified, error entry follows

Figure 2-6 Sequence of Receive Operation with End Criterion “End-of-Text Character”

Message frame

entered in receive

buffer

Expiration
of the
monitoring
time

Error when receiving

Waiting for valid

end code

Error entered in the

ST ATUS output of

the FB.

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2-17

Basic Principles of Serial Data Transmission

End Criterion: Fixed Frame Length

When data is received, the end of the message frame is detected when the
parameterized number of characters has arrived. The received data is accepted
from the CPU.

If the character delay time expires before the parameterized number of characters
has been reached, the receive operation is terminated. The character delay time is
used in this instance as the monitoring time. An error message is issued and the
message frame fragment is discarded.

Note the following if the message frame length of the received characters does
not match the parameterized fixed message frame length:

• Message frame length of received characters greater than parameterized fixed
message frame length:

All characters received after the parameterized fixed message frame length is
reached:

– Are discarded if the monitoring time expires at the end of the message

frame.

– Are merged with the next message frame if a new message frame is

received before the monitoring time expires.

• Message frame length of received characters less than parameterized fixed
message frame length:

The message frame:
– Is discarded if the monitoring time expires at the end of the message frame.
– Is merged with the next message frame if a new message frame is received

before the monitoring time expires.

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Basic Principles of Serial Data Transmission

The figure below illustrates a receive operation with the end criterion “fixed
message frame length”.

Waiting for

character

Character
arrived

Character received

with length control

and character delay

time

Message

Message frame buffered

End criterion for message frame identified, error entry follows

frame

complete

Message frame

entered in receive

buffer

Error when receiving

Waiting for

parameterized

number of

characters

Expiration
of the
monitoring
time

Figure 2-7 Sequence of Receive Operation with End Criterion “Fixed Message Frame

Length”

Error entered in the

ST ATUS output of

the FB.

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2-19

Basic Principles of Serial Data Transmission

Receive Buffer on the CP 440

The CP 440 receive buffer accommodates 2000 bytes. At parameterization you
can specify whether overwriting of data in the receive buffer should be prevented.
You can also specify the value range (1 to 10) for the number of buffered receive
message frames or use the entire receive buffer.

You can delete the CP receive buffer at startup. The setting can be made either by
using the parameterization interface or by calling the RES_RCV function block
(see Chapter 6).

The receive buffer on the CP 440 is a ring buffer:

• If two or more message frames are entered in the receive buffer of the CP 440,
the rule is that the oldest message frame is always transferred by the CP 440 to
the CPU.

• If you only ever want to send the most recent message frame to the CPU, you
must parameterize the value “1” for the number of buffered message frames

and deactivate the overwrite protection.

Note

If the constant reading out of the receive data in the user program is interrupted for
a while, you may find that when the receive data is requested again, the CPU first
receives old message frames from the CP 440 before it receives the most recent
one.

The old message frames are the ones that were on their way when transmission
between the CP 440 and the CPU was interrupted, or which had already been
received by the FB.

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Data Flow Control/Handshaking

Handshaking controls the data flow between two communication partners.
Handshaking ensures that data is not lost in transmissions between devices that
work at different speeds. Software handshaking is supported with XON/XOFF in
the CP 440.

Data flow control is implemented as follows on the CP 440:

• As soon as the CP 440 is switched by parameterization to the flow control
operating mode, it sends the XON character.

• When the parameterized number of message frames is reached, or
alternatively 50 characters before the receive buffer overflows (size of the
receive buffer: 2000 bytes), the CP 440 sends the XOFF character. If the
communication partner continues to send data regardless of this, the receive
buffer overflows and an error message is generated. The data received in the
last message frame is discarded.

• As soon as a message frame is fetched by the S7 CPU and the receive buffer
is ready to receive, the CP 440 sends the XON character.

Basic Principles of Serial Data Transmission

• If the CP 440 receives the XOF character, the CP 440 interrupts transmission.
If an XON character is not received before a parameterized time has elapsed,
the transmission is aborted and an appropriate error message (0708H) is
generated at the STATUS output of the function blocks.

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2-21

Basic Principles of Serial Data Transmission

Topologies Between the Communication Partners

The CP 440 can be used in different topologies in the RS422 and RS485 operating
modes.

Distinctions are drawn between connections with:

– Two nodes (point-to-point) and
– Several nodes (multipoint)

In these cases the CP 440 can be used as:

– Master or
– Slave

Figure 2-8 RS 422 Point-to-Point

Figure 2-9 RS 485 Point-to-Point

In the case of a master/slave topology, there must be an appropriate message
frame in the user program. Example: The master sends all the slaves a message
frame with address information. All the slaves listen in and compare the address
with their own. If the address is the same, the addressed slave sends its answer.

The senders of all slaves must be able to switch to low impedance.
In the case of a master/slave topology in RS422 operation:

– The master ’s sender is interconnected with the receivers of all the slaves.

2-22

– The slaves’ senders are interconnected with the master’s receiver.
– Only the receiver of the master and the receiver of one slave have a default

setting. All the other slaves function without default settings.

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Basic Principles of Serial Data Transmission

Master

Slave

Figure 2-10 RS 422 Multipoint

Slave

Slave

In the case of a topology in RS485 operation:

– The cable pair is interconnected for the send/receive line of all the nodes.
– Only the receiver of a node has a default setting. All the other modules

function without default settings.

Master

Slave

Figure 2-11 RS 485 Multipoint

Slave

The settings required for the different topologies can be made in the
parameterization interface in the “Interface” dialog box.

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Slave

2-23

Basic Principles of Serial Data Transmission

Note

When you run the ASCII driver in RS422 multipoint or RS485 mode, you must
take steps in the user program to ensure that only one node sends data at any
one time. If two nodes send data simultaneously, the message frame is corrupted.

2.2.3 Data Transmission with the 3964(R) Procedure

The 3964(R) procedure controls data transmission via a point-to-point connection
between the CP 440 and a communication partner. In addition to the physical layer
(layer 1), the 3964(R) procedure also incorporates the data link layer (layer 2).

Control Characters

During data transmission, the 3964(R) procedure adds control characters to the
user data (data link layer). These control characters allow the communication
partner to check whether the data has arrived complete and without errors.

The 3964(R) procedure analyzes the following control codes:

• STX Start of Text; Start of character string for transfer

• DLE Data Link Escape; Data connection escape

• ETX End of Text; End of character string for transfer

• BCC Block Check Character (only with 3964(R)); Block check

character

• NAK Negative Acknowledge; Negative acknowledgment

Note

If DLE is transmitted as an information string, it is sent twice so that it can be
distinguished from the control code DLE during connection setup and cleardown
on the send line (DLE duplication). The receiver then reverses the DLE
duplication.

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Priority

With the 3964(R) procedure, one communication partner must be assigned a
higher priority and the other partner a lower priority. If both partners begin
connection setup at the same time, the partner with the lower priority will defer its
send job.

Block Check Sum

With the 3964(R) transmission protocol, data integrity is increased by the additional
sending of a block check character (BCC).

Basic Principles of Serial Data Transmission

Message frame

STX Data DLE ETX BCC

02H  30H 31H  32H  10H  03H  20H

30 = 0011 0000
31 = 0011 0001

XOR = 0000 0001
32 = 0011 0010

XOR = 0011 0011
10 = 0001 0000

XOR = 0010 0011
03 = 0000 0011

XOR = 0010 0000

BCC  20

Figure 2-12 Block Checksum

The block checksum is the even longitudinal parity (EXOR logic operation of all
data bytes) of a sent or received block. Its calculation begins with the first byte of
user data (first byte of the message frame) after the connection setup, and ends
after the DLE ETX code on connection cleardown.

Note

If DLE duplication occurs, the DLE code is accounted for twice in the BCC
calculation.

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Basic Principles of Serial Data Transmission

Sending Data with 3964(R)

The figure below illustrates the transmission sequence when data is sent with the
3964(R) procedure.

CP 440 Communication partner

Start code (02H)
Pos. acknowledgment (10H)

1st data byte
2nd data byte




nth data byte

End code (10H)
End code (03H)
3964(R) only
Pos. acknowledgment (10H)

Figure 2-13 Data Traffic when Sending with the 3964(R) Procedure

Establishing a Send Connection

To establish the connection, the 3964(R) procedure sends the control code STX. If
the communication partner responds with the DLE code before the
acknowledgment delay time (ADT) expires, the procedure switches to send mode.

If the communication partner answers with NAK or with any other control code
(except for DLE or STX), or the acknowledgment delay time expires without a
response, the procedure repeats the connection setup. After the parameterized
number of unsuccessful setup attempts, the procedure aborts the connection setup
and sends the NAK code to the communication partner. The CP 440 reports the
error to the SEND_440 function block (STATUS output parameter).

STX
DLE

1st byte

2nd byte




nth byte

DLE
ETX

BCC

DLE

Connection

setup

User

data

Connection

cleardown

2-26

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Sending Data

If a connection is successfully established, the user data contained in the output
buffer of the CP 440 is sent to the communication partner with the selected
transmission parameters. The partner monitors the intervals between incoming
characters. The interval between two characters must not exceed the character
delay time.

If the communication partner sends the NAK control code during an active send
operation, the procedure aborts its transmission of the block and tries again as
described above, beginning with connection setup. If a different code is sent, the
procedure first waits for the character delay time to expire and then sends the NAK
code to change the mode of the communication partner to idle. Then the procedure
starts to send the data again with the connection setup STX.

Releasing a Send Connection

Once the contents of the buffer have been sent, the procedure adds the codes
DLE, ETX and in the case of 3964(R) only the block checksum BCC as the end
code, and waits for an acknowledgment code. If the communication partner sends
the DLE code within the acknowledgment delay time, the data block has been
received without errors. If the communication partner responds with NAK, any
other code (except DLE), or a damaged code, or if the acknowledgment delay time
expires without a response, the procedure starts to send the data again with the
connection setup STX.

Basic Principles of Serial Data Transmission

After the defined number of attempts to send the data block, the procedure stops
trying and sends an NAK to the communication partner. The CP 440 reports the
error to the SEND_440 function block (STATUS output parameter).

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

2-27

Basic Principles of Serial Data Transmission

Receiving Data with 3964(R)

The figure below illustrates the transmission sequence when data is received with
the 3964R procedure.

partner

CP 440Communication

Connection

setup

User
data

STX
DLE

1st byte

2nd byte



Pos. acknowledgment (10H)

Start code (02H)

1st data byte

2nd data byte



nth byte

DLE

Connection

cleardown

Figure 2-14 Data Traffic When Receiving with the 3964(R) Procedure

ETX

BCC

DLE

Pos. acknowledgment (10H)

Note

As soon as it is ready, the 3964(R) procedure sends a single NAK to the
communication partner to set the latter to idle.

nth data byte

End code (10H)
End code (03H)

3964(R) only




Establishing a Receive Connection

In idle mode, when there is no send job to be processed, the procedure waits for
the communication partner to establish the connection.

If no empty receive buffer is available during a connection setup with STX, a wait
time of 400 ms is started. If there is still no empty receive buffer after this time has
elapsed, the CP 440 reports the error (error message at the STATUS output of the
FB). The procedure sends an NAK and returns to idle mode. Otherwise, the
procedure sends a DLE and receives the data.

If the procedure receives any control code except for STX or NAK in idle mode, it
waits for the character delay time to expire, then sends the code NAK. The CP 440
reports the error to the RECV_440 function block (STATUS output parameter).

Point-to-point connection CP 440 Installation and Parameter Assignment

2-28

A5E00057742-02

Receiving Data

After a successful connection setup, the receive characters that are arrive are
stored in the receive buffer. If two consecutive DLE codes are received, only one of
these is stored in the receive buffer.

After each receive character, the procedure waits out the character delay time for
the next character. If this period expires before another character is received, an
NAK is sent to the communication partner. The system program reports the error
to the RECV_440 function block (STATUS output parameter). The 3964(R)
procedure does not initiate a repetition.

If transmission errors occur during receiving (lost character, frame error, parity
error, etc.), the procedure continues to receive until the connection is cleared
down, then an NAK is sent to the communication partner. A repetition is then
expected. If the block still cannot be received after the number of transmission
attempts specified in the static parameter record, or if the communication partner
does not start the repetition within a block wait time of 4 seconds, the procedure
aborts the receive operation. The CP 440 reports the first failed transmission and
the final abortion of the receive operation to the RECV_440 function block
(STATUS output parameter).

Basic Principles of Serial Data Transmission

Cleardown of a Connection for Receiving

If the 3964 procedure detects the string DLE ETX, it stops receiving and sends to
the communication partner a DLE if the block was received without errors. If the
block is damaged it sends an NAK. A repetition is then expected.

If the 3964(R) procedure detects the string DLE ETX BCC, it stops receiving and
compares the received BCC with the internally calculated longitudinal parity. If the
BCC is correct and no other receive errors have occurred, the 3964(R) procedure
sends a DLE and returns to idle mode. If the BCC is errored or a different receive
error occurs, an NAK is sent to the communication partner. A repetition is then
expected.

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

2-29

Basic Principles of Serial Data Transmission

Handling Errored Data

The figure below illustrates how errored data is handled with the 3964(R)
procedure.

partner

CP 440Communication

Receiving data

Start code (02H)
Pos. acknowledgment (10H)

1st data byte



nth data byte




End code (10H)
End code (03H)
3964(R) only
Neg. acknowledgment (15H)

New setup attempt

Figure 2-15 Data Traffic When Receiving Errored Data

STX
DLE

1st byte



nth byte




DLE

ETX
BCC
NAK

T

Connection

setup

User

data

Connection

cleardown

When DLE, ETX and BCC are received, the CP 440 compares the BCC of the
communication partner with its own internally calculated value. If the BCC is
correct and no other receive errors occur, the CP 440 responds with DLE.

Otherwise, the CP 440 responds with NAK and waits the block wait time (T) of
4 seconds for a new attempt. If, after the parameterized number of transmission
attempts, the block cannot be received, or if no further attempt is made within the
block wait time, the CP 440 aborts the receive operation.

2-30

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Initialization Conflict

The figure below illustrates the transmission sequence during an initialization
conflict.

Basic Principles of Serial Data Transmission

CP 440
(low priority)

Start code (02H)
Start code (02H)
Pos. acknowledgment (10H)

1st data byte
2nd data byte




nth data byte

End code (10H)
End code (03H)
3964(R) only
Pos. acknowledgment (10H)

2nd setup attempt

Start code (02H)
Pos. acknowledgment (10H)

STX
STX
DLE

1st byte

2nd byte




nth byte

DLE
ETX

BCC

DLE

STX
DLE

Communication partner
(higher priority)

Connection

setup

User

data

Connection

cleardown

Connection

setup

Figure 2-16 Data Traffic during an Initialization Conflict

If a device responds to the communication partner ’s send job (code STX) within
the acknowledgment delay time (ADT) by sending the code STX instead of the
acknowledgment DLE or NAK, an initialization conflict occurs. Both devices want to
execute a send job. The device with the lower priority withdraws its send job and
responds with the code DLE. The device with the higher priority sends its data in
the manner described above. Once the connection has been cleared down, the
lower-priority device can execute its send job.

To be able to resolve the initialization conflict, you must parameterize the
communication partners with different priorities.

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

2-31

Basic Principles of Serial Data Transmission

Procedure Errors

The procedure detects both errors which are caused by the communication partner
and errors caused by faults on the line.

In both cases, the procedure makes repeated attempts to send/receive the data
block correctly. If this is not possible within the maximum number of transmission
attempts set (or if a new error status occurs), the procedure aborts the send or
receive operation. It reports the error number of the first detected error and returns
to idle mode. These error messages are displayed in the STATUS output of the
FB.

If the system program regularly reports an error number at the STATUS output of
the FB for send and receive repetitions, this indicates occasional trouble affecting
the data traffic. The large number of transmission attempts compensates for this,
however. In this case you are advised to check the transmission connection for
possible sources of interference, because frequent repetitions reduce the
user-data rate and integrity of the transmission. The disturbance could also be
caused, however, by a malfunction on the part of the communication partner.

If BREAK occurs on the receive line (receive line interrupted), an error is displayed
at the STATUS output of the FB. No repeat is started. The BREAK status is
automatically reset as soon as the connection is restored on the line.

For every detected transmission error (lost character, frame or parity error), a
standard number is reported, regardless of whether the error was detected during
sending or receiving of a data block. The error is only reported, however, following
unsuccessful repetitions.

Startup of the 3964(R) Procedure

The figure below illustrates the startup of the 3964(R).

Power-up after restart of the CPU

or voltage recovery

Evaluate parameter

assignment

Initialize interface

2-32

Send NAK

G

Figure 2-17 Flow Diagram of the Startup of the 3964(R) Procedure

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Sending with the 3964(R) Procedure

The figure below illustrates sending with the 3964(R) procedure.

Basic Principles of Serial Data Transmission

G

High
priority

Low
priority

Intention to

2

send

G

G

Send NAK

W = 1

3

x = 1

Send STX

Start T

ADT

T > T

ADT

Send NAK

x <= 6

,

x <= 6

x > 6

x > 6

W + 1

x + 1

character except
DLE, STX or
invalid characters

DLE

Receipt not
permitted

STX

Wait for DLE
acknowledg-

ment

Send block,

poss.

duplicate DLE

Send NAK

Send DLE,

1

ETX

3964(R)

3964

Start T

ADT

T > T
character except

Wait for DLE
acknowledg-

ment

DLE or invalid
character

DLE

BCC only with 3964(R)
x = setup attempt counter
T

=500 ms (3964(R) T

ADT

W = transmission attempt counter
Immediate return to initial state at line break (BREAK)

ADT

=2s)

Sending completed

G

Figure 2-18 Flow Diagram of Sending with the 3964(R) Procedure

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

Send BCC

,

ADT

2-33

Basic Principles of Serial Data Transmission

Receiving with the 3964(R) Procedure (Part 1)

The figure below illustrates receiving with the 3964(R) procedure.

Characters except

STX, NAK

Note

NAK

4

G

Send DLE

Intention to send

2

Receive

STX

Repetition

expected

1

W +1

Start

T

NAKTIM

Wait

T > T

NAKTIM

Buffer free Buffer not free

Send NAK

5

Initialization

conflict, low

priority

4

T

= 400 ms

NAKTIM

W = transmission attempt counter
Immediate return to initial state at line break (BREAK)

G

Figure 2-19 Flow Diagram of Receiving with the 3964(R) Procedure (Part 1)

2-34

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Basic Principles of Serial Data Transmission

Receiving with the 3964(R) Procedure (Part 2)

The figure below illustrates receiving with the 3964(R) procedure.

4

Start T

Start T

char. delay time

Wait to

receive

characters

DLE

char. delay time

Correct
character
except
for DLE

Dual DLE

Invalid character
T > T

char. delay time

Note

NAK

Note NAK

Characters
except ETX, DLE

Wait for

ETX

T > T

ETX

3964(R)

3964

Start T

Wait for

NAK noted

Initialization conflict
noted, low priority

3

Times: T

char. delay time

W = transmission attempt counter
BCC only with 3964(R)
Immediate return to initial state at line break (BREAK)

= 220 ms, T

Send DLE

G

= 4 s

Block

Receipt completed

char. delay time

char. delay time

T > T

BCC

delay time

BCC incorrect

BCC

expected, start T

char.

Send NAK

W > 5

W <= 5

Note repetition

Wait for

STX

STX

1

BLOCK

T >
T

BLOCK

G

Figure 2-20 Flow Diagram of Receiving with the 3964(R) Procedure (Part 2)

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

2-35

Basic Principles of Serial Data Transmission

Receive Buffer on the CP 440

The CP 440 receive buffer accommodates 2000 bytes. At parameterization you
can specify whether overwriting of data in the receive buffer should be prevented.
You can also specify the value range (1 to 10) for the number of buffered receive
message frames or use the complete receive buffer.

You can delete the CP receive buffer at startup. The setting can be made either by
using the parameterization interface or by calling the RES_RCV function block
(see Chapter 6).

The receive buffer on the CP 440 is a ring buffer:

• If two or more message frames are entered in the receive buffer of the CP 440,
the rule is that the oldest message frame is always transferred by the CP 440 to
the CPU.

• If you only ever want to send the most recent message frame to the CPU, you
must parameterize the value “1” for the number of buffered message frames

and deactivate the overwrite protection.

Note

If the constant reading out of the receive data in the user program is interrupted for
a while, you may find that when the receive data is requested again, the CPU first
receives old message frames from the CP 440 before it receives the most recent
one.

The old message frames are the ones that were on their way when transmission
between the CP 440 and the CPU was interrupted, or which had already been
received by the FB.

2-36

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A5E00057742-02

Commissioning the CP 440

In Section You Will Find on Page

3.1 Sequence of Steps to Be Taken 3-2

3.2 Commissioning the Physical Interface 3-4

3

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

3-1

Commissioning the CP 440

3.1 Sequence of Steps to Be Taken

Before starting up the CP 440 you will need to perform the following steps in the
specified sequence.

1. Install the CP 440

2. Configure the CP 440

3. Parameterize the CP 440

4. Save the parameterization data

5. Create a user program for the CP 440

Installing the CP 440

Installing the CP 440 involves inserting it into the mounting rack of your
programmable controller.

For a detailed description, see Chapter 4.

Connecting the CP 440 to the Communication Partner

The connection to your communication partner is made using the connecting cable
described in Appendix B. You can find additional information on setting up the
physical interface in Section 3.2.

Configuring the CP 440

Configuring the CP 440 involves entering it in the configuration table. The CP 440
is configured using the STEP 7 software.

For a detailed description, see Section 5.1.

Parameterizing the CP 440

Parameterizing the CP 440 involves creating the specific parameters of the
protocols. You parameterize the CP 440 with the

Communication, Parameter Assignment

For a detailed description, see Section 5.2.

parameterization interface.

CP 440: Point-to-Point

Saving the Parameterization Data

Saving the parameterization data of the CP 440 involves saving the parameters,
downloading them to the CPU and transferring them to the CP 440. You use the
STEP 7 software to store the parameterization data.

3-2

For a detailed description, see Section 5.4.

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Creating a User Program for the CP 440

Programming the CP 440 involves configuring it for the associated CPU using the
STEP7 user program. The CP 440 is programmed using the language editors of
the STEP 7 software.

A detailed description of programming with STEP 7 is contained in the

Programming with STEP 7

Communication using the function blocks of the CP 440 is described in Chapter 6.
Chapter 9 contains a detailed programming example.

manual.

Commissioning the CP 440

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A5E00057742-02

3-3

Commissioning the CP 440

3.2 Commissioning the Physical Interface

If there is no communication with the partner device after configuration has been
completed, you should test the connection. To do this, proceed as follows:

1. What might be the possible cause:
– Is the polarity of the send/receive lines reversed?
– Are the default settings correct? Several defaults may have been set with

different polarity. The default settings may already be integrated in the

device on a permanent basis.
– Incorrect or missing terminating resistors?
– High byte and low byte mixed in the security word (e.g. CRC)?

2. How to proceed:
– First of all use the manual to check the line connection:

– Assignment (Appendix B)
– Polarity (Appendix B)
– Default settings (Section 5.3)

– Carry out a setup test

3. Carry out the simplest setup possible:
– Connect only 2 nodes to each another
– If possible, use 2-wire cable (RS485)
– Use a short connecting cable
– Terminating resistors are not required due to the short distance
– Send first in one direction and then in the other

4. Check:
Always monitor the TXD send and RXD receive LEDs during the following
operations:
Example 1: The polarity of the line is definitely correct

– The default settings (all options) vary
– Check the security word (e.g. CRC)
Example 2: The default settings are definitely correct
– Reverse the connections (note: cross both pairs of lines in the RS422)
– Check the security word (e.g. CRC)

3-4

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Commissioning the CP 440

Example 3: Neither correct polarity nor correct default settings known
– Reverse the connections (note: cross both pairs of lines in the RS422)
– If not OK, change the default settings (all options) with an appropriate

communication attempt

– If not OK, change the connections back, and change the default settings (all

options)
– Check the security word (e.g. CRC)
When setting up again, don’t forget to put back the terminating resistors you

removed.

5. Additional tips:
– If possible, connect an interface tester (possibly the V.24 converter →

RS22/485) to the connecting cable.

– Check the signal level using a measuring device (measure level to GND

(pin 8)).

– Some devices do not signal reception if data is being received but the CRC

security word is not correct.

– If necessary, replace the module to exclude the possibility of an electrical

defect.

Point-to-point connection CP 440 Installation and Parameter Assignment
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3-5

Commissioning the CP 440

3-6

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A5E00057742-02

Installing the CP 440

In Section You Will Find on Page

4.1 CP 440 Slots 4-2

4.2 Installing and Removing the CP 440 4-3

4.3 Installation Guidelines 4-4

4

Point-to-point connection CP 440 Installation and Parameter Assignment
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4-1

Installing the CP 440

4.1 CP 440 Slots

On the rack of the S7-400 programmable controller there are no specific slots
reserved for communication modules.

Position of the CP 440 on the Rack

The CP 440 can be plugged into any slot on the rack, with the following exception:
On all racks the power supply module occupies slots 1 to 3, depending on its

width.
For further information on slots, see /2/

/2/

S7-400/M7-400 Programmable Controllers, Hardware and Installation

Point-to-point connection CP 440 Installation and Parameter Assignment

4-2

manual

A5E00057742-02

4.2 Installing and Removing the CP 440

When installing and removing the CP 440, you must observe certain rules.

Tool

For installing and removing the CP 440 you require a 3.5 mm cylindrical
screwdriver.

Installation Sequence

To install the CP 440 on a rack, proceed as follows:

1. Remove the filler panel from the slot you want to use by gripping it where
marked and pulling it toward you.

2. Insert the CP 440 module and tilt it downward.

3. Screw the module down at the top and bottom with a torque of

0.8 ... 1.1 Nm.

Installing the CP 440

Removal Sequence

To remove the CP 440 from the rack, proceed as follows:

1. Undo the screws at the top and bottom of the module.

2. Tilt the module upward and remove it.

3. Replace the filler panel over the empty slot.

Note

The CP 440 can be hot-plugged and hot-pulled, in other words with voltage
applied. This means that the CP 440 can be replaced while the programmable
logic controller is in operation.

To avoid the CPU going into STOP, OB 83 (insert/remove interrupt) and OB 122
(I/O access error) must be programmed.

The CP 440 is parameterized automatically once it has been inserted. The CP 440
then resumes operation.

Point-to-point connection CP 440 Installation and Parameter Assignment
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4-3

Installing the CP 440

4.3 Installation Guidelines

To be Observed

The general installation guidelines for the S7-400 must be observed (see the

S7-400/M7-400 Programmable Controllers, Hardware and Installation

To meet the EMC (electromagnetic compatibility) values, the cable shield must be
connected to a shield bus.

manual).

4-4

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A5E00057742-02

Configuring and Parameterizing the CP 440

In Section You Will Find on Page

5.1 Configuring the CP 440 5-2

5.2 Parameterizing the Communication Protocols 5-3

5.3 Parameterization Data 5-4

5.4 Management of the Parameter Data 5-20

5.5 Subsequent Loading of Firmware Updates 5-21

Configuration Options

You configure and parameterize the CP 440 using STEP 7 or the

Point-to-Point Communication, Parameter Assignment

Table 5-1 Configuration Options for the CP 440

Product

CP 440 6ES7 440-1CS00-0YE0 As of version 5.1 As of version 4.0.2

parameterization interface.

Order Number Parameterized

Using the

Parameterization

Interface

5

CP 440:

Under STEP 7

Point-to-point connection CP 440 Installation and Parameter Assignment
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5-1

Configuring and Parameterizing the CP 440

5.1 Configuring the CP 440

After the CP 440 has been installed, you must make the CP 440 known to the
programmable logic controller. This process is known as “configuration”.

Requirements

The

CP 440 Point-to-Point Communication, Parameter Assignment

parameterization interface must be installed on the programming device/PC under
STEP 7 (see also Table 5-1).

Installation

The

CP 440: Point -to-Point Communication, Parameter Assignment

parameterization interface is supplied together with the function blocks and the
programming examples on a CD. Proceed as follows to install the
parameterization interface:

1. Insert the CD into the CD drive of your programming device/PC.

2. Under
double-clicking the “Add/Remove Programs” icon in “Control Panel”.

3. In the dialog box, select the CD drive and the Setup.exe file and start
installation.

4. Now follow the step-by-step instructions of the installation program.

Configuration

In the sense used here, configuration means entering the CP 440 in the
configuration table of the STEP 7 software. In the configuration table you enter the
rack, the slot and the order number of the CP 440. STEP 7 then automatically
assigns an address to the CP 440.

The CPU is now able to find the CP 440 in its slot in the rack by way of its address.

Requirements

Before you can enter the CP 440 in the configuration table of the STEP 7 software,
you must have created a project and a station using STEP 7.

Further Information

Configuration of S7-400 modules is described in detail in the

and Communication Connections STEP 7

Windows 95/NT

or

Windows 98

, start the dialog for installing software by

Configuring Hardware

manual

, V5.0

.

5-2

In addition, STEP 7’s online help system will provide you with all the assistance
you will need when configuring an S7-400 module.

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Configuring and Parameterizing the CP 440

5.2 Parameterizing the Communication Protocols

Once you have entered the CP 440 in the configuration table, you have to assign
parameters to the CP 440 communication processors and the interface
submodules of the CP 440.

Parameterization

The term “parameterization” is used in the following to describe the setting of
protocol-specific parameters. You set these parameters using the

Point-to-Point Communication, Parameter Assignment

You start the parameterization interface by double-clicking the order number
(CP 440) in the configuration table or by selecting the CP 440 and choosing the
Edit  Object Properties menu command. The “Properties - CP 440 ” dialog box
appears.

Click the “Parameters” button in order to select a protocol. Set the protocol and
double-click the icon for the transmission protocol (an envelope). This takes you to
the dialog box for setting the protocol-specific parameters.

parameterization interface.

CP 440:

Further Information

The

CP 440: Point-to-Point Communication, Parameter Assignment

parameterization interface is intuitive and easy to use; the procedure is the same
for all communication processors. For this reason, the parameterization interface is
not described in detail here.

The online help system provides all the assistance you will need when working with
the parameterization interface.

Note

To create a parameter record for the CP, you must select and save the protocol
settings at least once.

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A5E00057742-02

5-3

Configuring and Parameterizing the CP 440

5.3 Parameterization Data

You can set the response of the CP 440 to CPU STOP by means of the basic
parameters. By selecting different protocols, you can adjust your CP440
communication processor to suit the communication partner.

The sections that follow describe the basic parameters of the CP 440 and the
parameterization data for the ASCII driver and for the 3964(R) procedure.

5.3.1 Basic Parameters of the CP 440

Enter the basic parameters in the STEP 7 HW dialog box “Properties - CP 440 ”.
Open the dialog box by double-clicking the CP 440 in the configuration table of
STEP 7. Section 5.2 tells you how to enter the basic parameters of the CP 440.

The basic parameters are described in the table below.

Table 5-2 Basic Parameters of the CP 440

Parameter

Reaction to CPU Stop This parameter controls

Description Value Range Default Value

the storage of the
received frames in the
receive buffer.

You can find more
detailed information in
the following tables.

• Continue

• STOP

The transmission
process is terminated in
both cases. Frames are
received as described in
Tables 5-3 and 5-4.

• Continue

5-4

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Configuring and Parameterizing the CP 440

How is the Storage of the Received Message Frames Controlled by Setting the
“Reaction to CPU Stop” Parameter?

The response depends on whether or not flow control is used.

Table 5-3 Control of Message Frame Storage Without Flow Control

Without Flow Control

Reaction to CPU Stop:
Continue

Reaction to CPU Stop:
STOP

Table 5-4 Control of Frame Storage with Flow Control

With Flow Control

Reaction to CPU Stop:
Continue

Reaction to CPU Stop:
STOP

Saved Frames Frame Just Arriving New Message Frames

Retained Saved; discarded if the

Retained Discarded Discarded

Saved Frames Frame Just Arriving New Frames

Retained Saved; flow control is

Retained Further data cannot be

buffer is full

activated if the buffer is
full.

received because flow
control is activated.

Saved until the buffer is
full, then discarded

Saved; flow control is
activated if the buffer is
full.

Further data cannot be
received because flow
control is activated.

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-5

Configuring and Parameterizing the CP 440

5.3.2 Parameterization Data of the ASCII Driver

Using the parameterization data of the ASCII driver, you can adjust the CP440 to
suit the communication partner.

Parameterization Data of the ASCII Driver

Using the

CP440: Point-to-Point Communication, Parameter Assignment

interface,
specify the parameters for the physical layer (layer 1) of the ASCII driver. Below
you will find a detailed description of the parameters.

Section 5.2 describes how to enter parameterization data using the

Point-to-Point Communication, Parameter Assignment

parameterization interface.

CP440:

Note

The ASCII driver can be used in four-wire mode (RS 422) and two-wire mode
(RS 485).

At parameterization, you must specify the type of interface (RS 422 or RS 485).

5-6

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Protocol Parameters

The table below describes the protocol parameters.

Table 5-5 Protocol Parameters (ASCII Driver)

Configuring and Parameterizing the CP 440

Parameter

End ID of a
Receive
Message Frame

Character Delay
Time

Monitoring Time
for Missing
End ID

1st End ID

2nd End ID

Message Frame
Length

1

1

3

Description Value Range Default Value

Specifies the criterion that
indicates the end of each message
frame.

• On Expiry of Character

Delay Time

• On Receipt of Fixed

Number of Characters

• On Receipt of End

Character

The character delay time defines
the maximum permitted time
between 2 consecutively received
characters.

The character delay time is used
as the monitoring time for a
missing end code. This applies to
the following settings for the end
code

– On Receipt of Fixed

Number of Characters

– On Receipt of End

Character

First end code. • 7 data bits2:

1 to 65535 ms
The shortest character delay

time depends on the
transmission rate

bps

300
600
1200
2400
4800
9600
19200
38400
57600
76800
115200

0 to 7FH (hex)

• 8 data bits

0 to FFH (hex)

Second end code, if specified.
You can parameterize the following

for the end code:

– 1st end ID AND

2nd end ID

– 1st end ID OR 2nd end ID

When the end criterion is “fixed
message frame length”, the
number of bytes making up a
message frame is defined.

• 7 data bits

0 to 7FH (hex)

• 8 data bits

0 to FFH (hex)

1 to 200 (bytes) • 200

Character time
delay (ms)

130
65
32
16
8
4
2
1
1
1
1

2

:

2

:

2

:

• On Expiry of

Character
Delay Time

• 4 ms

• 3 (03H =

ETX)

• 0

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5-7

Configuring and Parameterizing the CP 440

Table 5-5 Protocol Parameters (ASCII Driver)

Parameter Default ValueValue RangeDescription

Transmission
pause between
the messages
related to the
monitoring time

1

Can only be set if the end criterion is an end-of-text character.

2

Depends on whether you parameterize 7 or 8 data bits for the character frame (see Table 5-6).

3

Can only be set if the end criterion is a fixed message frame length.

A pause equal to the length of the
monitoring time (for a missing end
ID) is inserted between two
message frames when sending so
that the partner can synchronize
(detect receipt of the message
frame).

• Yes

• No

• Yes

5-8

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Configuring and Parameterizing the CP 440

Transmission Rate/Character Frame

The table below describes the parameters for the transmission rate and character
frame.

Table 5-6 Transmission Rate/Character Frame (ASCII Driver)

Parameter

Transmission Rate Speed of data transmission in bps • 300

Description Value Range Default Value

• 600

• 1200

• 2400

• 4800

• 9600

• 19200

• 38400

• 57600

• 76800

• 115200

Start Bit During transmission, a start bit is prefixed to

each character to be sent.

Data Bits Number of bits to which a character is mapped. • 7

• 1 (fixed

value)

• 8

Stop Bits During transmission, a stop bit is appended to

every character to be sent to indicate the end of
the character.

Parity A sequence of information bits can be extended

to include another bit, the parity bit. The
addition of its value (0 or 1) brings the value of
all the bits up to a defined status. Thus the data
integrity is enhanced.

If “none” is specified for parity, no parity bit is
sent.

It is not possible to specify “none” if 7 data
bits are set.

• 1

• 2

• None

• Odd

• Even

• 9600

• 1

• 8

• 1

• Even

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-9

Configuring and Parameterizing the CP 440

Data Flow Control

In the following table the parameters for data flow control are described. Data flow
control is only possible when “Full Duplex (RS 422) Four-Wire Mode Point to Point”
is set.

Table 5-7 Data Flow Control (ASCII Driver)

Parameter

Data Flow Control Defines the type of data flow

control to be used.

XON Code

XOFF Code

Wait for XON after
XOFF (Wait Time
for CTS=ON)

1
2
3

1

1

3

Only in the case of XON/XOFF data flow control
Depends on whether you parameterize 7 or 8 data bits for the character frame (see Table 5-6).
Only in the case of XON/XOFF data flow control

Code for XON • 7 data bits2:

Code for XOFF • 7 data bits2:

Period of time for which the CP440
waits for the XON code or for
CTS=“ON” of the communication
partner when sending.

Description Value Range Default Value

• None

• None

• XON/XOFF

• 11 (DC1)

0 to 7FH (hex)

• 8 data bits

0 to FFH (hex)

2

:

• 13 (DC3)

0 to 7FH (hex)

• 8 data bits

0 to FFH (hex)

20 to 65535 ms
in 10 ms increments

2

:

• 20000 ms

Further Information

You will find more information on data flow control with XON/XOFF in
Section 2.2.2.

5-10

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Receive Buffer on the CP

The table below describes the parameters for the CP receive buffer.

Table 5-8 Receive Buffer on the CP (ASCII Driver)

Configuring and Parameterizing the CP 440

Parameter

Delete CP Receive
Buffer on Startup

Buffered Receive
Message Frames

Prevent
Overwriting

During power up or during transition of
the CPU from STOP to RUN, the CP
receive buffer is deleted.

You can specify the number of receive
message frames to be buffered in the CP
receive buffer or that are to use the whole
buffer. If you use the whole buffer of
2000 bytes, the number of buffered
receive message frames depends only
on the length of the frames.

If you specify “1” here, disable the
“Prevent Overwriting” parameter and
cyclically read the received data from the
user program, a current message frame
will always be sent to the CPU.

You can use this parameter to prevent
data in the receive buffer being
overwritten when the buffer is full.

Further Information

You can find further information on handling the receive buffer under “Receive
Buffer on the CP 440” in Section 2.2.2.

Description Value Range Default Value

• Yes

• No

• No

• 1 to 10

• Use Whole Buffer

• Yes

• Use Whole

Buffer

• Yes

• No

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-11

Configuring and Parameterizing the CP 440

Operating Mode/Initial State of the Receive Line

The table below contains descriptions of the operating mode/initial state of the
receive line for the X27 (RS 422/485) interface.

Table 5-9 X27 (RS 422/485) Interface (ASCII Driver)

Parameter

Operating Mode Specifies whether the

X27 (RS 422/485) interface is to
be run in full-duplex mode
(RS 422) or half-duplex mode
(RS 485).

(See also Section 2.2.2).

Initial State of
the Receive
Line (see also
Figure 5-1)

None:

Signal R(A)5 Volt, Signal
R(B)0 Volt:

Signal R(A)0 Volt, Signal
R(B)5 Volt:

Description Value Range Default Value

This setting only makes sense
for bus-capable special
drivers.

Break evaluation is possible
with this initial state. Cannot
be set with “Full Duplex
(RS422) Four-Wire Mode
Multipoint Master” and “Half
Duplex (RS485) Two-Wire
Mode”)

This initial state corresponds
to the idle state (no sender
active). Break evaluation is not
possible with this initial state.

• Full Duplex (RS 422)

Four-Wire Mode Point to
Point
Operating mode for
point-to-point
communication in four-wire
mode

• Full Duplex (RS 422)

Four-Wire Mode Multipoint
Master
Operating mode for
multipoint communication
in four-wire mode if the CP
is a master

• Full Duplex (RS 422)

Four-Wire Mode Multipoint
Slave
Operating mode for
multipoint connection in
four-wire mode if the CP is
a slave

• Half Duplex (RS 485)

Two-Wire Mode
Operating mode for
point-to-point or multipoint
communication in two-wire
mode The CP can be a
master or slave.

• None

• Signal R(A)5 Volt Signal

R(B) 0 Volt (Break
Evaluation)

• Signal R(A)0 Volt

• SignalR(B)5 Volt

• Full Duplex

(RS 422)
Four-Wire
Mode Point
to Point

• Depends on

the operating
mode set

5-12

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Initial State of the Receive Line

Figure 5-1 shows the wiring of the recipient at the X27 (RS 422/ 485) interface:

Configuring and Parameterizing the CP 440

none

0 V

R(A)5V/R(B)0V

5 V

5 V

R(A)0V/R(B)5V

0 V

Figure 5-1 Wiring of the Recipient at the X27 (RS 422/485) Interface (ASCII Driver)

R(B) +

R(A) –

R(B) +

R(A) –

R(B) +

R(A) –

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-13

Configuring and Parameterizing the CP 440

5.3.3 Parameterization Data of the 3964(R) Procedure

Using the parameterization data of the 3964(R) procedure, you can adjust the
CP440 to suit the communication partner.

Parameterization Data of the 3964(R) Procedure

Using the

CP 440 Point-to-Point Communication, Parameter Assignment

parameterization interface you set the parameters for the physical layer (layer 1)
and the data link layer (layer 2) of the 3964(R) procedure Below you will find a
detailed description of the parameters.

Section 5.2 describes how to enter the parameterization data using the

Point-to-Point Communication, Parameter Assignment

parameterization interface.

CP440:

Note

The 3964(R) procedure can only be used in four-wire mode.

5-14

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Protocol

Ack. del

The following table describes the 3964(R) protocol.

Table 5-10 3964(R) Protocol

Configuring and Parameterizing the CP 440

Parameter

3964 Default Values
Without Block Check

3964(R) No Default Values
With Block Check

3964 No Default Values
Without Block Check

3964(R) No Default Values
With Block Check

Description Default Value

• The protocol parameters are set to default values.

• If the CP440 detects the string DLE ETX, it stops

receiving and sends DLE to the communication
partner if the block was received without errors, or
NAK if there were errors.

• The protocol parameters are set to default values.

• If the CP440 detects the string DLE ETX BCC, it

stops receiving and compares the received block
check character (BCC) with the longitudinal parity
calculated internally. If the BCC is correct and no
other receive errors have occurred, the CP440
sends the DLE code to the communication partner
(in the event of an error, the NAK code is sent).

• The protocol parameters are programmable.

• If the CP440 detects the string DLE ETX, it stops

receiving and sends DLE to the communication
partner if the block was received without errors, or
NAK if there were errors.

• The protocol parameters are programmable.

• If the CP440 detects the string DLE ETX BCC, it

stops receiving and compares the received block
check character (BCC) with the longitudinal parity
calculated internally. If the BCC is correct and no
other receive errors have occurred, the CP440
sends the DLE code to the communication partner
(in the event of an error, the NAK code is sent).

3964(R) Default
Values With
Block Check:

Char. delay time
= 220 ms

ay time
= 2000 ms
Setup
attempts = 6
Transmission
attempts = 6

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-15

Configuring and Parameterizing the CP 440

Protocol Parameters

You can only set the protocol parameters if you have not set the default values in
the protocol.

Table 5-11 Protocol Parameters (3964(R) Procedure)

Parameter

Character Delay
Time

Acknowledgment
Delay Time

Setup Attempts This parameter specifies the

Transmission
Attempts

The character delay time defines the
maximum amount of time permitted
between two incoming characters
within a message frame.

The acknowledgment delay time
defines the maximum amount of time
permitted for the partner’s
acknowledgment to arrive during
connection setup (time between STX
and partner’s DLE acknowledgment)
or cleardown (time between DLE ETX
and partner’s DLE acknowledgment).

maximum number of attempts the
CP440 is allowed in order to establish
a connection.

This parameter specifies the
maximum number of attempts
permitted to transfer a message frame
(including the first one) in the event of
an error.

Description Value Range Default Value

20 ms to 65535 ms in
10 ms increments

The shortest character
delay time depends on the
transmission rate

300 bps 60 ms
600 bps 40 ms
1200 bps 30 ms
2400 to
115200 bps 20 ms

20 ms to 65535 ms in
10 ms increments

The shortest
acknowledgment delay
time (ADT) depends on
the transmission rate:

300 bps 60 ms
600 bps 40 ms
1200 bps 30 ms
2400 to
115200 bps 20 ms

1 to 255 6

1 to 255 6

220 ms

2000 ms
(550 ms with
3964 and no
block check)

5-16

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Configuring and Parameterizing the CP 440

Transmission Rate/Character Frame

The following table describes the transmission rate/character frame.

Table 5-12 Transmission Rate/Character Frame (3964(R) Procedure)

Parameter

Transmission Rate Speed of data transmission in bps • 300

Description Value Range Default Value

• 600

• 1200

• 2400

• 4800

• 9600

• 19200

• 38400

• 57600

• 76800

• 115200

Start Bit During transmission, a start bit is prefixed to

each character to be sent.

Data Bits Number of bits to which a character is mapped. • 7

• 1 (fixed

value)

• 8

Stop Bits During transmission, a stop bit is appended to

every character to be sent to indicate the end of
the character.

Parity A sequence of information bits can be extended

to include another bit, the parity bit. The
addition of its value (0 or 1) brings the value of
all the bits up to a defined status. The data
integrity is thus enhanced.

If “none” is specified for parity, no parity bit is
sent.

It is not possible to specify “none” if 7 data
bits are set.

Priority A partner has high priority if its send job takes

precedence over the send job of the other
partner. A partner has low priority if its send job
must wait until the send job of the other partner
has been dealt with. With the 3964(R)
procedure, you must parameterize both
communication partners with different priorities,
i.e. one partner is assigned high priority, the
other low.

• 1

• 2

• None

• Odd

• Even

• High

• Low

• 9600

• 1

• 8

• 1

• Even

• Low

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-17

Configuring and Parameterizing the CP 440

Receive Buffer on the CP

The table below describes the parameters for the CP receive buffer.

Table 5-13 Receive Buffer on the CP (3964(R) procedure)

Parameter

Delete CP Receive
Buffer on Startup

Buffered Receive
Message Frames

Prevent
Overwriting

During power up or during transition of
the CPU from STOP to RUN the CP
receive buffer is deleted.

You can specify the number of receive
message frames to be buffered in the CP
receive buffer or to use the whole buffer.
If you use the whole buffer of 2000 bytes,
the number of buffered receive message
frames depends only on the length of the
frames.

If you specify “1” here, disable the
“Prevent Overwriting” parameter and
cyclically read the received data from the
user program, a current message frame
will always be sent to the CPU.

You can use this parameter to prevent
data in the receive buffer being
overwritten when the buffer is full.

Further Information

You can find further information on handling the receive buffer under “Receive
Buffer on the CP 440” in Section 2.2.2.

Description Value Range Default Value

• Yes

• No

• No

• 1 to 10

• Use Whole Buffer

• Yes

• Use Whole

Buffer

• Yes

• No

5-18

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Initial State of the Receive Line

The table below contains a description of the initial state of the receive line for the
X27 (RS 422) interface. RS 485 operation is not possible in conjunction with the
3964(R) procedure.

Table 5-14 X27 (RS 422) Interface (3964(R) Procedure)

Configuring and Parameterizing the CP 440

Parameter

Initial State of the
Receive Line

The figure below shows the wiring of the recipient at the X27 (RS 422) interface:

Description Value Range Default Value

None: This setting only makes sense
with bus-capable drivers.

R(A)5V/R(B)0V: Break evaluation is
possible with this initial state.

R(A)0V/R(B)5V: Break evaluation is not
possible with this initial state.

(See also Figure 5-2.)

none

R(A)5V/R(B)0V

None R(A)5V/R(B)0V

Signal R(A)5
Volt (Break
Evaluation)

SignalR(B)0 Volt
SignalR(A)0 Volt

Signal R(B)5
Volt

R(B) +
R(A) –

0 V

R(B) +
R(A) –

R(A)0V/R(B)5V

Figure 5-2 Wiring of the Recipient at the X27 (RS 422) Interface (3964(R) Procedure)

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5 V

5 V

R(B) +
R(A) –

0 V

5-19

Configuring and Parameterizing the CP 440

5.4 Management of the Parameter Data

The configuration and parameterization data of the CP 440 is saved in the current
project (on the hard disk of the programming device/PC).

Data Storage

When you exit the configuration table (see Section 5.1) by choosing the Station >
Save or Station > Save As menu command, the configuration and

parameterization data (including the module parameters) is automatically saved in
the project/user file you have created.

Downloading the Configuration and Parameters to the CPU.

You can download the configuration and parameterization data to the CPU from
the programming device (by choosing PLC > Download). The CPU puts the
parameters into effect as soon as they are loaded.

The module parameters are automatically transferred to the CP 440 in the
following cases:

• When they are downloaded to the CPU and the CP 440 can be reached via the
S7-400 backplane bus

• After power up during startup of the CPU, as soon as the CP 440 can be
reached via the S7-400 backplane bus

Unchanged parameters have the default value (see Section 5.3).

Further Information

You can find out how to do the following in the

Communication Connections STEP 7

• Save the configuration and parameters.

• Download the configuration and parameters to the CPU.

• Read, modify, copy and print the configuration and parameters.

Configuring Hardware and

manual:

5-20

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

5.5 Uploading Firmware Updates

Firmware updates can be uploaded to the operating-system memory of the CP 440
as patches.

Configuring and Parameterizing the CP 440

Firmware updates are loaded using the

Parameter Assignment

Basic Firmware

The CP 440 is shipped with basic firmware preinstalled.

Requirements

The prerequisites for loading firmware updates are:

• To update the firmware of the CP using the parameterization interface, you first
have to create a valid project under HWCONFIG and download it to the CPU.

• The instructions accompanying the firmware update always indicate the
destination directories for the files.

The ..\CP440.nnn path always identifies the firmware version.

CP 440: Point-to-Point Communication,

parameterization interface.

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

5-21

Configuring and Parameterizing the CP 440

Downloading Firmware

You download the firmware update to the CP 440 with the aid of the

Point-to-Point Communication, Parameter Assignment

parameterization interface.

CP 440:

Proceed as follows:

1. Switch the CPU to STOP mode.

2. Start the parameterization interface (see also Section 5.2):
In SIMATIC Manager: File > Open Object > Project > Open Hardware Config

> double-click CP 440 > choose the “Parameter” button.

3. Choose the Options > Firmware Update menu command.

Result:

If a connection can be established to the CP 440, the current module firmware
status is displayed.

If there is no firmware loaded on the CP 440, “ – – – – “ appears. This can
occur, for example, if a firmware update is canceled. The old firmware is
deleted in this case. You have to upload firmware to the module before it can be
restarted.

4. 3. Click the “Find File ...” button to select the firmware to be loaded
(header.upd).

Result:

The version of the firmware you select is displayed under “Status of selected
firmware:”.

5. Click the “Load Firmware” button to start uploading to the CP 440. You are
prompted for confirmation. The upload procedure is canceled immediately if you
click the “Cancel” button.

Note:

Before the basic firmware is deleted from the module, the CP 440 checks the
MLFB No. of the firmware to be downloaded in order to ensure that the
firmware is suitable for the CP 440.

Result:

The new firmware is loaded into the operating-system memory of the CP 440.
Under “Done” you can follow the progress of the operation in the form of a bar
chart and as a percentage. The module is immediately ready for operation
following the firmware update.

Power Failure During Firmware Uploading

If there is a failure when the firmware is being uploaded, the process must be
repeated. The module then has the state “CP 440 without module firmware” (see
Table 5-15).

5-22

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

LEDs

LED indicators for firmware update:

Table 5-15 LED Indicators for Firmware Update

Configuring and Parameterizing the CP 440

Status

Firmware update in
progress

Firmware update
completed

CP 440 without module
firmware

Hardware fault during
firmware update

INTF/EX

TF

on on on on – –

on off off off – –

flashing
(2Hz)

Flashing
(2Hz)

FAULT

on off off Module

Off Flashing

TXD RXD Comment Remedy

firmware
deleted,
firmware
update
canceled,
firmware
update still
possible

(2Hz)

Flashing
(2Hz)

Delete/write
failed

Reload the
firmware

Switch power
supply to
module off and
then on again
and reload the
firmware.

Check module
for defects.

Displaying the Hardware and Firmware Release

You can view the current version of the CP 440 hardware and firmware in
in the “Module Status” dialog box. To access this dialog box:

In SIMATIC Manager: File > Open Object > Project > Open HW Config >
Station > Open Online > and double-click the CP 440 module.

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

STEP 7

5-23

Configuring and Parameterizing the CP 440

5-24

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

Communication Using Function Blocks

In Section You Will Find on Page

6.1 Communication Using Function Blocks 6-2

6.2 Overview of the Function Blocks 6-3

6.4 Using the Function Blocks 6-5

6.5 Programming the Function Blocks 6-18

6.6 General Information on Program Processing 6-23

6.7 Technical Specifications of the Function Blocks 6-24

6

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6-1

Communication Using Function Blocks

6.1 Communication Using Function Blocks

Communication between the CPU, the CP 440 and a communication partner takes
place via the function blocks and the protocols of the CP 440.

Communication Between the CPU and CP 440

The function blocks form the software interface between the CPU and the CP 440.
They must be called cyclically from the user program.

Restriction in Multicomputing Operation

In multicomputing operation only one CPU can access the CP because
communication between the CPU and CP is not multicomputing-compatible.

Communication Between the CP 440 and the Communication Partner

The transmission protocols are implemented on the CP 440. By means of the
protocol, the interface of the CP 440 is adapted to the interface of the
communication partner.

This enables you to link an S7 programmable logic controller with any
communication partner that can handle the ASCII driver and the 3964(R)
procedure.

Calling the Function Blocks in Interrupt OBs

It is not permissible to simultaneously call a function block in OB1 and in the
interrupt OB (time OBs). The reason for this is that the function block cannot be
called again if an interrupt OB triggers an interruption. If you need to call the
function block in OB1 and in the interrupt OB, you must disable the interrupts
(SFC 41) in the lower priority OB before the FB call and enable them again after
the FBs have executed.

6-2

Point-to-point connection CP 440 Installation and Parameter Assignment

A5E00057742-02

6.2 Overview of the Function Blocks

The S7-400 programmable logic controller provides you with a number of function
blocks that initiate and control communication between the CPU and the CP 440
communication processor in the user program.

Function Blocks

The table below contains the function blocks of the CP 440 and describes their
purpose.

Table 6-1 Function Blocks of the CP 440

Communication Using Function Blocks

FB/FC

FB 9 “RECV_440” The RECV_440 function block allows you to receive data

from a communication partner and store it in a data block.

FB 10 “SEND_440” The SEND_440 function block allows you to send all or part

of a data block to a communication partner.

FB 11 “RES_RECV” The RES_RECV function block enables you to reset the

receive buffer of the CP 440.

Meaning Protocol

Form of Delivery and Installation

The function blocks of the CP 440 are on CD along with the parameterization
interface, the programming examples and the manual.

The function blocks are installed together with the parameterization interface.
Installation is described in Section 5.2. After installation, the function blocks are
stored in the CP 440 library.

You can open the library in STEP 7 SIMATIC Manager by choosing File > Open >
Library under CP PTP\CP 440\Blocks.

To work with the function blocks, you only need to copy the required function block
to your project.

ASCII driver, 3964
(R) procedure

ASCII driver, 3964
(R) procedure

ASCII driver, 3964
(R) procedure

Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02

6-3

Communication Using Function Blocks

6.3 Notes on Program Structure

In order to use the speed of the CP 440 to optimum effect, you should heed the
following when you create your user program:

In a short cycle (see also “CP 440 1CYC Programming Example” in Chapter 9):

• Only one run of the SEND_440 function block with REQ=0 and one run with
REQ=1 is necessary for data transmission (creating the positive edge at the
REQ input). The calls can be made directly one after the other. This makes it
possible to carry out one data transmission per cycle.

• Program the call of the SEND_440 FB with REQ=1 (this activates the FB) at
the end of the program. This ensures optimum use of the time between two
cycles, which can be relatively long in a short cycle.

In a long cycle:

• Call the SEND_440 and RECV_440 FBs several times throughout the program.

• Call the SEND_440 and RECV_440 FBs in the time OB (disable the interrupts

in the lower priority OBs).

Note when using interrupts (time OBs) that calling the corresponding OB requires
quite a lot of time (you can find exact times in your CPU manual). You should
therefore check in each case whether the FBs could be processed more effectively
by modifying your program.

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6.4 Using the Function Blocks

The following sections describe what you must take into account when supplying
the function blocks with parameters.

STATUS Display on the FB

Please note the following with reference to the STATUS display on the function
blocks:

Note

The DONE, NDR, LEN, ERROR and STATUS parameters are set for only one
block run. To display the STATUS, you should therefore copy it to a free data area.

If the job runs through with DONE =’1’, the job was executed without errors.

Communication Using Function Blocks

This means:

• Using the ASCII driver: The job was sent to the communication partner. It is not
certain that the data was also received by the communication partner.

• Using the 3964(R) procedure: The job was sent to the communication partner
and acknowledged affirmatively by the communication partner. It is not certain
that the data was also transferred to the partner CPU.

Simultaneously Processed Jobs

Only one SEND_440 FB, one RECV_440 FB and one RES_RECV FB can be
programmed in the user program for each CP 440 used.

In addition, you can only use the following data blocks because the states required
for the internal execution of the FB are stored in the instance data block:

• 1 instance data block for the SEND_440 FB

• 1 instance data block for the RECV_440 FB

• 1 instance data block for the RES_RECV FB

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Communication Using Function Blocks

Data Consistency

Please note the following to ensure consistent data transmission:

• Sender: Only access the send DB again once all the data has been transferred
(DONE = 1).

• Receiver: Only access the receive DB again once all the data has been
received (NDR = 1). Then disable the receive DB (EN_R = 0) until you have
processed the data.

6.4.1 The S7 Transmits Data to a Communication Partner, 10 SEND_440 FB

The SEND_440 FB transfers a data field from a data block, specified by the
DB_NO, DBB_NO and LEN parameters, to the CP 440. The SEND_440 FB is
called cyclically for data transmission or, alternatively, statically (without conditions)
in a time-controlled program.

The data transmission is initiated by a positive edge at the REQ input. A data
transmission operation can run over several calls (program cycles), depending on
the amount of data involved.

The SEND_440 FB can be called cyclically with the signal state “1” at the
parameter input R. This terminates the transmission to the CP 440 and resets the
SEND_440 FB to its initial state. Data that has already been received by the
CP 440 is still sent to the communication partner. If the signal state “1” is at the R
input statically, this means that sending is deactivated.

The LADDR parameter specifies the address of the CP 440 to be addressed.

Error Display on the SEND_440 FB

The DONE output indicates that the job has been completed without errors.
ERROR indicates whether an error has occurred. If there was an error, the
corresponding event number is displayed for STATUS (see Section 8.3). If there is
no error, STATUS = 0. DONE and ERROR/STATUS are also output when
SEND_440 FB is RESET (see Figure 6-1). In the event of an error, the binary
result BR is reset. If the block is terminated without errors, the binary result has the
status “1”.

Note

6-6

The SEND_440 function block does not have a parameter check. If there are
invalid parameters, the CPU branches to the STOP mode.

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What To Do

Communication Using Function Blocks

Block Call

STL Representation LAD Representation

CALL SEND_440, I_SEND_440

REQ: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
LEN: =
DONE: =
ERROR: =
STATUS: =

Note

SEND_440, I_SEND_440

EN ENO
REQ DONE
R ERROR
LADDR STATUS
DB_NO
DBB_NO
LEN

The parameters EN and ENO are only present in the graphical representation
(LAD or FBD). The block is started with EN = TRUE. If the function is completed
without errors, ENO = TRUE is set. To process these parameters, the compiler
uses the binary result BR.

The binary result BR is set to the signal state “1” if the block was terminated
without errors. If there was an error, the BR is set to “0”.

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6-7

Communication Using Function Blocks

Assignment in the Data Area

The SEND_440 FB works with an instance DB (I_SEND_440). The DB number is
specified in the call. The data in the instance DB cannot be accessed.

Note

Exception: If the error STATUS == W#16#1E0F occurs, you can consult the
SFCERR variable for more details of the error (see Section 8.3). This error
variable can only be loaded via symbolic access to the instance DB.

Parameters of the SEND_440 FB

The following table lists the parameters of the SEND_440 FB.

Table 6-2 Parameters of the SEND_440 FB

Name

REQ INPUT BOOL Initiates job at positive

R INPUT BOOL Aborts job Current job is aborted. Sending

LADDR INPUT INT Basic address of the CP

DB_NO INPUT INT Data block number Send DB no.:CPU-specific,

DBB_NO INPUT INT Data byte number 0  DBB_NO  8190

LEN INPUT INT Data length 1  LEN  200, specified

1

DONE

ERROR

STATUS

1

1

1

The parameter is available until the next call of the FB.

Type Data Type Comment Permitted Values,

Comment

edge

is blocked.
The basic address is taken from

440

OUTPUT BOOL Job completed without

errors

OUTPUT BOOL Job completed with errors STATUS parameter contains

OUTPUT WORD Error specification If ERROR == 1, STATUS

STEP 7.

zero is not allowed

transmitted data as of data byte;
offset is CPU-specific

in number of bytes
ST ATUS parameter == 16#00;

error information

parameter contains error
information

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Time Sequence Chart for the SEND_440 FB

The figure below illustrates the behavior of the DONE and ERROR parameters,
depending on how the REQ and R inputs are wired.

REQ

R

DONE

ERROR

Communication Using Function Blocks

Sending job

Completion without errors

Figure 6-1 Time Sequence Chart for the 10 SEND_440 FB

1st /n. part of SEND

RESET transmitted

Completion with errors

RESET transmitted

Completion without errors

SEND job

not executed

(sending

deactivated)

Note

The REQ input is edge-triggered. A positive edge at the REQ input is sufficient. It
is not necessary for the RLO (result of logical operation) to be at “1” during the
whole transmission.

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Communication Using Function Blocks

6.4.2 S7 Receives Data from a Communication Partner, 9 RECV_440 FB

The RECV_440 FB transmits data from the CP 440 to an S7 data area specified
by the DB_NO, DBB_NO and LEN parameters. The RECV_440 FB is called
cyclically for data transmission or, alternatively, statically in a time-controlled
program (without conditions).

With the (static) signal state “1” at the EN_R parameter, the check as to whether
data is to be read by the CP 440 is enabled. An active transmission can be aborted
with the signal state “0” at the EN_R parameter. The aborted receive job is
terminated with an error message (STATUS output). Receiving is deactivated as
long as the EN_R parameter has the signal state “0”. A data transmission can run
over several calls (program cycles), depending on the amount of data involved.

If the function block detects the signal state “1” at the R parameter, the current
send job is aborted and the RECV_440 FB is set to the initial state. Receiving is
deactivated as long as the R parameter has the signal state “1”.

The LADDR parameter defines the CP 440 to be addressed.

Error Display on the RECV_440 FB

The NDR output indicates that the job has been completed without errors (all data
read). ERROR indicates that an error has occurred. If there was an error, the
corresponding event number is displayed for STATUS (see Section 8.3). If there is
no error, STATUS = 0. NDR and ERROR/STATUS are also output when
RECV_440 FB is RESET (LEN == 16#00 parameter) (see Figure 6-2). In the event
of an error, the binary result BR is reset. If the block is terminated without errors,
the binary result has the status “1”.

Note

The RECV_440 function block does not have a parameter check. If there are
invalid parameters, the CPU branches to the STOP mode.

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What To Do

Communication Using Function Blocks

Block Call

STL Representation LAD Representation

CALL RECV_440, I_RECV_440

RECV_440, I_RECV_440
EN_R: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
NDR: =
ERROR: =

EN ENO
EN_R NDR
R ERROR
LADDR LEN
DB_NO STATUS

DBB_NO L_TYP
LEN: =
STATUS: =

Note

The parameters EN and ENO are only present in the graphical representation
(LAD or FBD). The block is started with EN = TRUE. If the function is completed
without errors, ENO = TRUE is set. To process these parameters, the compiler
uses the binary result BR. The binary result is set to the signal state “1” if the block
was terminated without errors. If there was an error, the BR is set to “0”.

Assignment in the Data Area

The RECV_440 FB works with an instance DB (I_RECV_440). The DB number is
specified in the call. The data in the instance DB cannot be accessed.

Note

Exception: If the error STATUS == W#16#1E0E occurs, you can consult the
SFCERR variable for more details of the error (see Section 8.3). This error
variable can only be loaded via a symbolic access to the instance DB.

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Communication Using Function Blocks

Parameters of the RECV_440 FB

The following table lists the parameters of the RECV_440 FB.

Table 6-3 Parameters of the RECV_440 FB

Name

Type Data Type Comment Permitted Values,

Comment

EN_R INPUT BOOL Enables reading of data
R INPUT BOOL Aborts job Current job is aborted. Receiving

is disabled.

LADDR INPUT INT Basic address of CP 440 The basic address can be found

in the configuration table in
STEP 7.

DB_NO INPUT INT Data block number Receive DB No.:

CPU-specific, zero is not
allowed

DBB_NO INPUT INT Data byte number Offset is CPU-specific

1

NDR

OUTPUT BOOL Job completed without

ST ATUS parameter == 16#00;

errors, data accepted

ERROR

1

OUTPUT BOOL Job completed with errors STATUS parameter contains

error details

1

LEN

STATUS

OUTPUT INT Length of message frame

received

1

OUTPUT WORD Specification of the error If ERROR == 1, STATUS

1  LEN  200, specified
in number of bytes

parameter contains error
information

1

The parameter is available until the next call of the FB!

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