Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 30)

Installation
Chapter 3
3-6
Switch 4 relates only to diagnostic commands sent to the KF2 module
from a remote Data Highway station. Since only computers can transmit
diagnostic commands, the remote station must be a computer connected to
the Data Highway by means of another KF2 module. At the computer
station, the setting of Switch 4 does not affect any diagnostic commands
that the computer sends to its local KF2 module. The local module
always retransmits the command message over the Data Highway without
executing it. Figure 3.4 illustrates these concepts.
Figure 3.4
Effect of Switch 4 on Diagnostic Commands
Computer 1770-KF2 Module
1770-KF2 Module
1771-KG Module
PLC-2/15 Processor
Switch 4 ON
To Other Stations
Data
Highway
Link
Diagnostic Command Path
Reply Message Path
Computer 1770-KF2 Module
1770-KF2 Module
1771-KG Module
PLC-2/15 Processor
Switch 4 OFF
To Other Stations
Data
Highway
Link
11691
You can have more than one computer station on a network, and one
computer can transmit diagnostic commands to the others. At the
receiving computer station, if Switch 4 is OFF, the local KF2 module will
pass the diagnostic commands to the computer. In such cases, you will
have to write computer application programs to handle those commands at
the receiving station. If Switch 4 is ON at the receiving station, the local
KF2 module itself will execute the incoming diagnostic commands.