Rockwell Automation 1747-SCNR ControlNet Scanner Module Reference Manual - Manual (Page 40)

Publication 1747-RM623D-EN-P - June 2006
4-6 Work with the ControlNet Explicit Message Instruction
Definitions for Message Status Bits on the General Tab
See the table that lists the various status bits associated with the CEM
instruction as displayed in the CEM instruction setup screen.
• Timeout bit TO (word 0, bit 8) is set when the scanner times out
the message either due to no response from the target device or
due to no reply being returned within the configured timeout
period. The ER bit will be set at the same time the TO bit is set.
This bit is reset the next time the message rung goes from false
to true. Do not set or reset this bit. It is informational only.
• Error bit ER (word 0, bit 12) is set when the message has failed
to complete successfully. This bit is reset the next time the
message rung goes from false to true. Do not set or reset this bit.
It is informational only.
• Done bit DN (word 0, bit 13) is set when the message has
completed successfully. This bit is reset the next time the
message rung goes from false to true. Do not set or reset this bit.
It is informational only.
• Enabled bit EN (word 0, bit 15) is set after the message rung
goes from false to true and the scanner accepts this message
because it is not currently processing any other explicit
messages. (The scanner can process only one CEM instruction at
a time.) If the message rung goes false before the scanner
accepts this message, then the enable bit will remain off and the
message will not be executed. This bit is reset when the
message has completed with either the Done bit set or the error
bit set and the message rung goes false. If the message rung
conditions remain true, you may retrigger the message
instruction by resetting this bit after either the ER or DN bit has
been set, indicating that the previous execution has completed.
• Waiting for Slot bit WS (word 0, bit 10) is set when the message
rung goes from false to true, but the scanner is still processing
another CEM instruction. To ensure that this message gets
processed, you must leave the message rung conditions true
until the WS bit is reset and the EN bit is set, indicating that the
scanner has accepted this message for processing. Do not set or
reset this bit. It is informational only.
CEM Instruction Setup Screen Status Bit
Bit Definition Bit Mnemonic Bit Address
Timeout TO 08
Error ER 12
Done DN 13
Enabled EN 15
Waiting for slot WS 10