Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo Instrukcja Użytkownika Pobierz pdf (Strona 79)

Asynchronous Link Protocols

Chapter 4

4-36

station alone may not work, since it could be that the only way to free up

space is to send a message to the master.

Line Monitoring

When monitoring half-duplex protocol in two-wire mode, you need to

monitor only one line. The example below shows a message sent by the

master and a reply sent by the slave in answer to a poll. Slave responses

are in boldface.

Message from Master to Slave:

DLE SOH STN DLE STX message DLE ETX BCC DLE ACK

Message Sent from Slave to Master in Response to Poll:

DLE ENQ STN BCC DLE STX message DLE ETX BCC DLE ACK

Poll with a DLE EOT in Response:

DLE ENQ STN BCC DLE EOT

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Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo Instrukcja Użytkownika Strona 79