Rockwell Automation 1203-SM1 SLC to SCANport Communication Module - Manual (Page 67)

Appendix
B
Publication 1203–5.9 –– October 1996
SCANport Messaging
This appendix contains information to help you use SCANport. The
following topics are covered:
•
message and reply structures
•
examples of SCANport message structures
Before you can send a message, you need to copy the message into
one of the M0 message buffers.
SCANport messages access data structures within the SCANport
device. These data structures are called objects. An object contains
information for a particular purpose. For example, a parameter
object can contain information such as parameter values, parameter
names, scaling information, and units.
Figure B.1 shows the first M0 message buffer structure.
Figure B.1
SLC to SCANport Module M0 Buffer 0 Message Structure
Service
Class
Instance
Attribute
Request Length = n
Req Data 2
Req Data n
Req Data 1
...
M0:e.b00
M0:e.b01
M0:e.b02
M0:e.b03
M0:e.b04
M0:e.b05
M0:e.bxx
e = slot location
b = buffer 0–7
Header
Information
Appendix Objectives
Message and Reply
Structures