!"##$%&'()&%*+,-."$*-+)-/
7"8$9/
!"#$%&'()
5–11
This section focuses on examples that use a 1771-KGM PLC-2 master
which interfaces over an RS-232-C multidrop to PLC-5s used as slaves.
If you are writing your own master driver or need more information on
Allen-Bradley half-duplex protocol, refer to the Data Highway/Data
Highway Plus Protocol and Command Set Reference Manual (publication
1770-6.5.16).
The examples in this section discuss message transfers as they occur with a
PLC-5 using a 1785-KE Series B.
The 1785-KE acts as a slave on the multidrop and listens for messages
addressed to a PLC-5 on its Data Highway Plus link. Thus, the master can
send a message addressed directly to a PLC-5 and the 1785-KE will hear
the message and pass it through. Therefore, you can use the same network
addressing for PLC5/1785-KE slave nodes as for PLC-2/1771-KG slave
nodes.
Figure 5.3 below will be used for the examples of this section. Note that a
PLC-2/1771-KG (#012) is shown as a slave in the figure to illustrate the
fact that the 1785-KE Series B allows both PLC-5’s and PLC-2’s to be
addressed identically on the multidrop.
;.0,'&()<O
LB.-0(%"&(234)567(T&'.&B(S(*-(#(8,:%.9'*$
G$$:./#%.*-(OH(8,:%.9'*$
G$$:./#%.*-B(M.%"(%"&
234)Z67(T&'.&B(S