Rockwell Automation Publication 1444-UM001D-EN-P - June 2018 479
CIP Objects Appendix A
Data types consisting of multiple bytes are transferred in little-endian format
(least significant byte first).
A data communication session starts at the first service request and ends after
the final response of the exchange or after timeout of 30 seconds. Although
three sessions are available, a reset remains good practice for freeing up
resources for new Advanced Data transfer requests.
Expected flow is as follows: Request - Data - Data - Data (as required) - Session
Reset.
0x4B Advanced CM Data Request
Advanced CM data processing is started and the results are retrieved using a
two-part set of commands that are sent as a series of request/response messages
(using connected messages reduce messaging overhead).
An Advanced CM data request service is used to initialize and start a session.
The desired parameters are passed to the system to begin the processing of the
advanced CM data. The anticipated time for the processing to be completed is
returned. After the processing time expires, the requester can ask for the data
using the second part of the command set.
The instance and attribute can be set to 1, but they are ignored.
Table 225 - Object Specific Services
Service
Code
Implementation Service Name Description of Service
Class Instance
0x4B x x Advanced CM Data
Request
This service specifies the data processing that is
being requested. Being 'on-demand', this service
triggers that processing to take place.
0x4C - x Advanced CM Data
Record Request
This service is used to return the requested data.
0x4D x x Advanced CM Data
Session Reset
This service can be used to reset (finish early) the
specified session instance. Only sessions that are
associated with an advanced measurement is
reset. The reset request includes the advanced
session instance number from the last successful
Advanced CM Data Request (0x4B) response.
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