Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo Manual de usuario descargar pdf (Pagina 63)

Asynchronous Link Protocols

Chapter 4

4-20

Examples

If a line monitor were connected to the wires between Stations A and B,

and only the A to B subsystem were active, the following would be

observed:

Normal Message

Message with Parity or BCC Error and Recovery

DLE STX ...xxx.. DLE ETX BCC

Message with ETX Destroyed

DLE STX .....xxxx [timeout] DLE ENQ

Good Message but ACK Destroyed

Messages Being Sent in Both Directions

Combined

Path 1:

DLE NAK

DLE STX .... DLE ETX BCC

DLE STX ... DLE ETX BCC

DLE STX ... DLE ETX BCC DLE STX .... DLE ETX BCC

DLE STX ...

DLE STX ... DLE ETX BCC

DLE ACKPath 2:

DLE STX .... DLE ETX BCC

DLE ACK

DLE STX .... DLE ETX BCCPath 1:

Path 2: DLE ACK

Path 2: DLE NAK DLE ACK

Path 1:

Path 2:

Path 1:

DL xxx CK

[timeout] DLE ENQ DLE STX ... etc.

DLE ACK

Path 2:

Path 1:

Path 4:

Path 3:

DLE ACK DLE ACK

DLE ACK

DLE STX

DLE STX.... DLE ETX BCC

DLE STX ... DLE ETX BCCCircuit AB: DLE STX .... DLE ETX BCC DLE ACK DLE STX

Circuit BA: DLE STX ... DLE ACK .... DLE ETX BCC DLE ACK DLE STX

Embedded Response

ACK on AB delayed slightly because ETX BCC are indivisible.

Embedded Response Option

To simplify the design of the receiver, you can, in some cases, disable

transmission of embedded responses by turning off communication option

Switch 2 of Switch Group SW-1. If this switch is OFF, the KF2 module’s

multiplexer will not allow response codes to be sent within a message.

Instead, it will delay response codes until after it receives the next DLE

ETX BCC.

1 2 ... 58 59 60 61 62 63 64 65 66 67 68 ... 234 235

Comentarios a estos manuales

Sin comentarios

Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo Manual de usuario Pagina 63

Comentarios a estos manuales

Relacionado con productos y manuales para Equipo Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo