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Chapter 4
Communicating with the KF3
Communicating with
DH 485 Master Devices
Communicating with
DH 485 Slave Devices
4 6
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
00
1770 KF3
SLC 500
SLC 500
SLC 500
01
1770 KF3
SLC 500
SLC 500
02
SLC 500
1770 KF3
SLC 500
SLC 500
SLC 500
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.
Address on DH 485
Address on DF1
Half Duplex
01
001
02
002
05
005
09
011
00
040
01
041
02
042
00
100
01
101
02
102
03
103
04
104
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