Allen-Bradley Micro800

Communication instructions Chapter 9
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015 221
Message execution process (Error)
The following table describes the message conditions and bit status for each
execution step identified in the timing diagram when an error occurs during
execution.
Step Message description Bit status
1
Rung condition goes TRUE.
Message execution is enabled.
EN bit is set.
All other bits are cleared.
2
Message buffer is acquired. EW bit is set.
3
Message transmission starts. EW bit is cleared.
ST bit is set.
4
Message transmission times out. EW and ST bits do not change.
4-6
As rung condition goes FALSE. EN bit is cleared.
ER bit is set.
Message execution timing diagram (Error)
The following timing diagram shows a typical pattern when an error occurs during
execution.