470 Rockwell Automation Publication 1444-UM001D-EN-P - June 2018
Appendix A CIP Objects
Channel Select
The Dynamix 1444 as part of an 0x4C service response returns the following.
Bit 01234567
Channel 0123 Reserved
Table 208 - 0x4C Service Responses
Byte Offset
Within Structure
Structure Member Data Type Description
0 SessionInstance USINT The host copies the SessionInstance returned here into each subsequent CM Record Request. Up to 3
instances are supported except when reading Live Data. See the IMPORTANT note about the
SpecialRequest structure on page 391
.
1 DynamicChannel USINT Indicates the dynamic channel for this record. Channels 0…3 are valid channels.
2 Completed Records UINT Incremented each time that another complete record has been transferred. There are often several
packets per completed record.
4 RecordSize UDINT For a given session, the RecordSize returned here is fixed.
8 PacketCountDown DWORD The host copies the PacketCountDown returned here into each subsequent CM Record Request.
When the PacketCountDown reaches 0, the session is complete and the final value in
CompletedRecords is all that is transferred.
12 Status DINT Any of the following can be returned:
• eUnrecognizedSession (1)
• e maxSessionsReached (2)
• ePacketCountOutOfSequence (3)
• eInvalidBufferSelect(4)
• eNoDataAvailable (5)
•eGeneralError (6)
For all successful requests eSUCCESS (0) is returned, any other value ends the session.
16 Data Array DWORD[50] Each record is an array of DWORDs of size RecordSize. This array of records can be large. It is the
calling applications responsibility to handle these records appropriately. The DWORD type is just a
placeholder for the actual types in the data structure that maps to this RecordArray. See the next
section for details.
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