Rockwell-automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command Uživatelský manuál stáhnout pdf (Strana 56)

4–2 Using Full-duplex Protocol to Send and Receive Messages

Publication

17706.5.16 - October 1996

With full-duplex protocol, a link uses two physical circuits for

two-way simultaneous message transmission (command or reply

message packets). These two physical circuits provide

communication on four logical paths:

Figure 4.1

Data paths for twoway simultaneous operation

path 1

path 2

path 3

path 4

receiver B

transmitter A

transmitter Breceiver A

circuit 1

circuit 2

•On the first circuit, transmitter A sends messages to receiver B (path 1) and receiver A sends response

control symbols (DLE ACK, DLE NAK) to transmitter B (path 3).

•On the second circuit, transmitter B sends messages to receiver A (path 4) and receiver B sends

response control symbols (DLE ACK, DLE NAK) to transmitter A (path 2).

•All message and symbols on the first circuit are traveling in the same direction (node A to node B) and all

messages and symbols on the second circuit are traveling in the opposite direction (B to A).

Fullduplex Protocol

Message Transmission

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Rockwell-automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command Uživatelský manuál Strana 56