Rockwell Automation 1747-SDN SLC 500 DeviceNet Scanner Module User Manual - Manual (Page 101)

Publication 1747-UM655B-EN-P - June 2007
DeviceNet Explicit Messaging 101
Control Block Layout
The control block layout is shown below.
SLC 5/0x DeviceNet Explicit Message (DEM) Control Block Structure
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 0
Word 0 EN DN ER WS AB Error Code
Word 1 IMR Message Timeout Preset
Word 2 Message Timeout Accumulator
Word 3 Message Timer Scaled Zero
Word 4 Unused
Word 5 Unused
Word 6 Transaction ID Scanner Command
Word 7 Scanner Port (always 0x00) Size of Send Data (in bytes)
Word 8 Service Code Target MAC ID
Word 9 Reserved (not transmitted) Class
Word 10 Instance
Word 11 Reserved (not transmitted) Attribute (optional)
Word 12 Transaction Send Data
(next 26 words)
…
Word 37
Word 38 Transaction ID Scanner Status
Word 39 Scanner Port (always 0x00) Size of Reply Data (in bytes)
Word 40 Reply Service Code Target MAC ID
Word 41 Transaction Reply/Receive Data
(next 29 words)
…
Word 69