Rockwell Automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command - Manual (Page 88)

Chapter
7
Publication 1770Ć6.5.16 - October 1996
Communication Commands
This chapter contains the format you should use when sending
communication commands to Allen-Bradley processors.
Use this key to help learn the conventions that depict the
communication commands listed in this chapter:
This text describes how the command is used.
FNC CMD
CMD
C
R
command description
command
format
reply
format
command code function code
command
processors that can
use the command
each block represents one byte
data varies up to a maximum number of bytes
Unless otherwise stated, values are shown in hexadecimal.
• PLCĆ3
command name
Message packets
The message packets for these commands include STS and possibly
EXT STS fields that contain status and error code information.
For more information on these bytes, see Chapter
8 , “Message
Packet Status Codes (STS, EXT STS).”
Protecting data files from write access
Using a PLC-5/11, -5/20, 5/30, -5/40, -5/60, or -5/80 processor,
you can also specify privileges to protect data files from write
access on a DH+ link. Using an SLC 5/02, 5/03, or 5/04 processor,
you can specify static file protection to protect data files from write
access from any of the communication channels.
Important: In some cases, switch settings on an interface module
can disable a command at a PLC/SLC node.
For additional information on your module’s switch
settings, refer to that module’s user documentation.
(For a list of related publications and products, refer to
the preface of this manual.)
In addition to the commands listed in this chapter, we’ve also
included examples:
Section Page
PLCĆ5 Type/Data Parameter Examples 7-36
SLC 500 Information 7-38
Reading and Writing SLC 500 Data (using SLC terminology) 7-38
Reading and Writing SLC 500 Data (using PLCĆ2 terminology) 7-38
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