Allen-Bradley ControlLogix 5570 Reference Manual page 71

Table 13 - Behavior Differences
Tag Read/
Write Source 5380 Controllers
HMI Allows
MSG Allows
I/O Update Allows
Produce/ Allows
Consume
Other User Blocks
Tasks
Motion Allows
Planner
Blocks - Prevents source data values from change by communications during application execution.
Allows - Communications can change source data values during application execution.
The items that are highlighted in this table are where 5370 and older
controllers and the 5380 controllers behavior differ.
UID/UIE
5370 Controllers 5380 Controllers
Blocks Blocks
Blocks Blocks
Allows Blocks
Allows Blocks
Blocks Blocks
Allows Blocks
Because the 5370 and 5380 controllers have 32-bit data integrity, this only
applies to data structures larger than 32 bits. If word-level integrity is your
primary concern, the 32-bit data integrity does not impact your data use.
Good programming practice dictates the use of two unique words at the
beginning and the end of data. The controller validates the words to assure the
entire structure has data integrity. We recommend that the handshake data is
changed and the application code validates it every transaction before the
controller application code or higher-level system reading controller data acts
on it.
Rockwell Automation Publication 1756-RM100F-EN-P - October 2018
Replacement Considerations with CompactLogix and Compact GuardLogix Systems
Tag Access
CPS
5370 Controllers
Blocks
Blocks
Blocks
Blocks
Blocks
Blocks
Periodic Task
5380 Controllers 5370 Controllers
Allows Blocks
Allows Blocks
Allows Allows
Allows Allows
Allows Allows
Allows Allows
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