396 Rockwell Automation Publication 1444-UM001D-EN-P - June 2018
Appendix A CIP Objects
It is recommended to store the first packet request and response packet to the
file. Thereafter, store the record array payload that is contained within each
subsequent packet. If this procedure is followed, the packet arrangement
within the file is as follows:
• RecordRequest Packet
• RecordResponse Packet (with first packet payload at the end)
• Second Response Packet payload
• Subsequent Response Packet payloads
• Last Response Packet payload
Instigate further sessions to retrieve data from any other required buffers or
channels. Retrieval of any record from the file can then be accomplished as
follows.
1. Open the file.
2. Read a record with size of CM Record Request from the head of the file.
3. Access the BufferSelect variable to determine the type of record the file
holds.
4. Read a record with size CM Record Response from the file pointer.
5. Access the RecordSize variable to determine the size of the record.
6. Start at the address of the first Record in the Data Array in the first CM
Record Response.
a. To index to any record, use the RecordSize to seek to the correct
point in the file.
b. Read out the record of size RecordSize.
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