8.4 Basics - Protocols
Protocols define a set of instructions or standards that enable computer to establish com-
munication connections and exchange information as error free as possible. A commonly
established protocol for the standardization of the complete computer communication is
the so called ISO/OSI layer model, a model based upon seven layers with rules for the
usage of hardware and software
Chap. 8.2 ‘Basics - ISO/OSI reference model’
The following protocols are used:
n
Siemens S7 connections
n
Open communication
–
TCP native according to RFC 793
–
ISO on TCP according to RFC 1006
–
UDP according to RFC 768
With the Siemens S7 connection large data sets may be transferred between PLC sys-
tems based on Siemens STEP
®
7. Here the stations are connected via Ethernet. Precon-
dition for the Siemens S7 communication is a configured connection table, which contains
the defined connections for communication. Here NetPro from Siemens may be used.
Properties:
n
A communication connection is specified by a connection ID for each connection
partner.
n
The acknowledgement of the data transfer is established from the partner station at
level 7 of the ISO/OSI reference model.
n
At the PLC side FB/SFB Yaskawa handling blocks are necessary for data transfer for
the Siemens S7 connections.
More information about the usage of these blocks may be found in the
manual "SPEED7 Operation List" from Yaskawa.
Overview
Siemens S7 connections
System 300S
+
Deployment Ethernet communication - productive
Basics - Protocols
HB140 | CPU | 315-4PN23 | en | 18-02
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