Introduction; Communication Protocols - Siemens 3964R User Manual

Wonderware Siemens
3964R I/O Server

Introduction

The Wonderware
remainder of this user's guide) is a Microsoft
as a communication protocol server. It allows other Windows application programs
access to data within the SIMATIC
devices). The server allows the PC to access a Siemens PLC through a CPU or CP
which supports the 3964R protocol with RK512. While the server is primarily intended
for use with Wonderware InTouch
Microsoft Windows program capable of acting as a DDE, FastDDE, or SuiteLink
client.

Communication Protocols

Dynamic Data Exchange (DDE) is a communication protocol developed by Microsoft
to allow applications in the Windows environment to send/receive data and instructions
to/from each other. It implements a client-server relationship between two concurrently
running applications. The server application provides the data and accepts requests
from any other application interested in its data. Requesting applications are called
clients. Some applications such as InTouch and Microsoft Excel can simultaneously be
both a client and a server.
FastDDE provides a means of packing many proprietary Wonderware DDE messages
into a single Microsoft DDE message. This packing improves efficiency and
performance by reducing the total number of DDE transactions required between a
client and a server. Although Wonderware's FastDDE has extended the usefulness of
DDE for our industry, this extension is being pushed to its performance constraints in
distributed environments.
NetDDE
over local area networks and through serial ports. Network extensions are available to
allow DDE links between applications running on different computers connected via
networks or modems. For example, NetDDE supports DDE between applications
running on IBM
applications running on non-PC based platforms under operating environments such as
VMS
 Siemens 3964R I/O Server (referred to as the server through the

extends the standard Windows DDE functionality to include communication

compatible computers connected via LAN or modem and DDE-aware
 
and UNIX .
 
Windows application program that acts

S5 and S7 family of PLCs (also referred to as

(version 3.01 or later), it may be used by any
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