Rockwell Automation 1779-KP3R DATA HIGHWAY II - Manual (Page 31)

Installing the 1779-KP3
Communication Interface
Chapter 2
2Ć15
Figure 2.8
Backup Cabling With the KP3
S4A KP3
Primary PLC-3
S4A KP3
Backup PLC-3
Backup Backup
A A
Backup
B
Backup
B
1775-CBB or
1779-CBC Cable
11008-I
Important: Because of the various options for this cable, refer to
the backup cable configuration information in the PLC–3 Backup
Concepts Manual (publication 1775–6.3.1).
1775-CBB
Cable
This method provides faster switchover of communications between
primary and backup PLC–3s. Use this method when:
the application process requires that switchover occur as fast as
possible and that the backup KP3 switches to primary operation without
waiting for the backup PLC–3 to take control of the I/O.
the KP3 module is involved in many time–critical transactions.
you plan to send time–critical messages to the PLC–3 processor.
Because of the various options for this cable, refer to the backup cable
configuration information in the PLC–3 Backup Concepts Manual
(publication 1775–6.3.1).
Important: The 1775–CBB cable assembly has one end that you can
configure. When making cables, note the location of the locking
connector tab on the module to be certain of the correct connector
position. The S4A and MX modules both have the locking tab on the
opposite side in comparison to the KP3. The connection between the S4A
and the KP3 module is a straight through cable in relation to pin 1 of the
connectors (figure 2.9).
The 1779–CBC cable is shipped assembled at both ends.