Rockwell Automation 1747-SCNR ControlNet Scanner Module Reference Manual User Manual

Page 52

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Publication 1747-RM623D-EN-P - June 2006

A-2 Local Database Access Using PLC-5 MSG Instructions

• Data-table address in destination processor - The destination

file must be N7, otherwise the request will be rejected.

• PLC-5 Typed Read and PLC-5 Typed Write: N7:XX

where XX is the zero-based element offset in the Local
Database file

• PLC-2 Unprotected Read, PLC-2 Unprotected Write: YY

where YY is the octal zero-based element offset in the Local
Database file

• Port number - set to 2 for the ControlNet network
• Flags:

• .TO - forces a message to timeout
• .EW - indicates that the message is waiting for an open

connection

• .CO - indicates that the message is sent
• .ER - indicates that the message was terminated due to an

error

• .DN - indicates that the message was sent without error
• .ST - indicates that the message was started
• .EN - indicates that the message instruction is enabled

• Error code – indicates the error when the .ER is set

For each concurrently enabled MSG instruction, the PLC-5 processor
opens an unscheduled connection.

All messages sent over different connections to the 1747-SCNR
scanner have the same priority.

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