Watlow LogicPro Manual do Utilizador descarregar pdf (Página 275)

Doc.# 28002-00 Rev 3.00 Watlow Anafaze 259

Dynamic Data Exchange

Dynamic Data Exchange (DDE) is a communication protocol

designed to allow Windows applications to send and receive

data and instructions to other Windows applications.

Dynamic Data Exchange takes place between a client

application and a server application. The client initiates the

exchange by establishing a conversation with the server so

that it can send transactions (requests for data or service) to

the server. The server responds by providing the requested

data or services.

A server can have many clients at the same time, and a client

can request data from multiple servers. Applications can be

both client and server. The client terminates a conversation

when it no longer needs the server’s data or services.

How to Access a Remote Item

A DDE Server uses a three-level name to identify the data unit

that the server can exchange:

• Server name — is a string that a server application

responds to when a client attempts to establish a

conversation with a server. A client must specify this

service name to be able to establish the conversation.

Although a server may respond to many server names,

most servers respond to only one. In the case of

LogicPro, the server name is LP_DDE.

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Watlow LogicPro Manual do Utilizador Página 275