Rockwell Automation 1770-KF3 DH-485 Communication Interface User Manual - Manual (Page 39)

Communicating with the KF3
Chapter 4
4Ć6
The group number is used by the KF3 to create a unique half-duplex DF1
address for each node on the DH-485 networks. The nodes’ addresses
would be as follows:
Table 4.B
Multidrop Addresses
Group Number Device Address on DHĆ485 Address on DF1
HalfĆDuplex
00 1770ĆKF3
SLC 500
SLC 500
SLC 500
01
02
05
09
001
002
005
011
01 1770ĆKF3
SLC 500
SLC 500
00
01
02
040
041
042
02 SLC 500
1770ĆKF3
SLC 500
SLC 500
SLC 500
00
01
02
03
04
100
101
102
103
104
The KF3 operates as a token-passing master on the DH-485 network. It
can communicate with other DH-485 master stations (such as the SLC 500
series of programmable controllers) and with DH-485 slave devices.
The KF3 communicates with other master stations using the Allen-Bradley
programmable controller command set. A detailed description of this
command set is found in the Data Highway/Data Highway Plus/DH-485
Protocol and Command Set Manual.
The DH-485 network also supports slave (nontoken-passing) devices.
The KF3 communicates with slaves using a special PLC command (CMD)
byte.
Application programs communicate with slaves via SRD (Send and
Receive Data) messages on DH-485. The SRD message is a link layer
service provided on DH-485. The Programmable Controller Command Set
has been extended to provide SRD messages by setting the PCCC CMD
byte to 09.
The following section on packet formats is advanced information, not
required for common applications.
Communicating with
DHĆ485 Master Devices
Communicating with
DHĆ485 Slave Devices