Preface, Contents
Layer 1 and Layer 2 PPI
Definition
1
Layer 7 PPI Definition
2
Appendices
Examples of PPI Network Traffic
A
Recommended Testing
B
Edition: 1
C79000-G7074-C222-01
S7-200 Point-to-Point Interface
Communication
Manual
SIMATIC
Index-2
S7-200
Point-to-Point Interface Communication
C79000-G7074-C222-01
!
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precautions are not taken.
!
Caution
indicates that minor personal injury or property damage can result if proper precautions are not taken.
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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
This device and its components may only be used for the applications described in the catalog or the
technical
description, 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.
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SIMATIC
and Siemens
are registered trademarks of SIEMENS AG.
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:
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have checked the contents of this manual for agreement with the hard
-
ware
and software described. Since deviations cannot be precluded entirely
,
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.O. Box 4848, D- 90327 Nuremberg
Siemens
AG 1998
T
echnical data subject to change.
Siemens Aktiengesellschaft
i
S7-200
Point-to-Point Interface Communication
C79000-G7074-C222-01
Preface
Purpose
This
manual tells you how to implement the master/slave serial communication
protocol called Point-to-Point Interface (PPI).
PPI protocol is based upon the European Standard EN 50170 and uses the seven
layer OSI model. PPI protocol implements layers 1, 2, and 7. The remaining layers
3, 4, 5, and 6, are null layers in the PPI implementation.
There are two basic types of PPI devices: masters and slaves.
Master devices initiate all messages and thus must hold the token in order to
initiate messages. A master device that does not currently hold the token can
optionally be designed to respond to a PPI request as a slave.
Slave devices are not token holders and therefore can never initiate a message.
Audience
This manual is designed for engineers and programmers who already have a
general knowledge of how to implement a communication protocol using a
programming language.
Scope of the Manual
The
information contained in this manual pertains to the communication protocol
used by the S7-200 PLCs.
Related Information
Refer
to the following documentation for more detailed information about selected
topics:
S7-200 Programmable Controller System manual
describes installing and
programming the S7-200 PLCs.
PG 702 Programming Device User Manual
describes installing and
programming the PG 702 programming device.
Preface
ii
S7-200
Point-to-Point Interface Communication
C79000-G7074-C222-01
How to Use This Manual
This
manual contains both English and German language.
Y
ou should read the entire manual one time to understand how the protocol
functions. Y
ou can then refer to the table of contents to find specific information.
iii
S7-200
Point-to-Point Interface Communication
C79000-G7074-C222-01
Contents
1 Layer
1 and Layer 2 PPI Definition
1.1
Layer 1 PPI Definition
1-2.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Layer
2 PPI Definition
1-3.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Valid
Request/Response Message Pairs and Exceptions
1-8.
. . . . . . . . . . . . .
1.4 Token
Handling
1-13.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 Procedures for T
oken Handling
1-14.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reception
of the T
oken 1-14.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmission
of the T
oken 1-15.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gap
Maintenance
1-16.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initializing
or Re-Initializing the T
oken Ring
1-17.
. . . . . . . . . . . . . . . . . . . . . . . . .
Token
Rotation T
ime 1-18.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Polling 1-19
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Master
Controller States
1-20.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Offline 1-22
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Listen Token 1-22.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Active
Idle
1-23.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Claim Token 1-24.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use Token 1-24.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Await
Data Response
1-25.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check
Access T
ime 1-25.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pass Token 1-26.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check T
oken Pass
1-27.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Await
Status Response
1-27.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Layer
7 PPI Definition
2.1
Layer 7 PPI Definition – Communication Services
2-2.
. . . . . . . . . . . . . . . . . . .
2.2 Header
Definition
2-3.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview 2-3
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Header
Descriptions
2-3.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Parameter
Block and Data Block Definition
2-5.
. . . . . . . . . . . . . . . . . . . . . . . . .
Overview
of Parameter Block
2-5.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview
of Data Block
2-5.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4 Simplified
Representation of the Communication Sequence
2-6.
. . . . . . . . . .
2.5 Establish
Association
2-7.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Request
Parameter Block
2-8.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Response
Parameter Block
2-9.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6 Data
Read/Write Using the ANY Pointer
2-10.
. . . . . . . . . . . . . . . . . . . . . . . . . . .
