Rockwell Automation 1771-KA2 Communication Adapter Module - Manual (Page 98)

Station Interfacing
Chapter 8
8-6
Unprotected bit write
These commands have the same execution sequence and memory access
as the same commands from a communication adapter module.
In addition to these commands, the command set from the computer
includes the following, which can be executed by a PLC-2 family
processor:
Privileged read
Privileged write
Diagnostic loop
Enter download mode
Enter upload mode (New for 1771-KA2)
Exit upload/download mode
Diagnostic read
Diagnostic counters reset
Set data table size (New for 1771-KA2)
Diagnostic Status
Privileged commands give the computer the capability to read from or
write into the entire processor memory. This includes both data
commands and user program areas. Privileged commands are used
chiefly to load programs from a computer to a station processor on the
Data Highway.
During program downloading, outputs are held in their last state by the
processor. However, at the computer programmer’s option, privileged
write commands can also be used to change data table values during a
download of program. (Refer to publications 1771-6.5.8 and
1771-6.5.15.)
Diagnostic commands affect only the communication adapter module at a
station, not the station processor. These commands access the read/write
memory of the communication adapter module. They provide a check of
module activity and permit computer control of specific aspects of
communication adapter module behavior. A summary of diagnostic
commands and their functions is given in Table 8.A.