Rockwell Automation 1336T ControlNet Frn1.02 Rev 1.5 - Manual (Page 51)

4–9 Using Unscheduled Messaging
Publication 1336 FORCE–5.18 ––March, 1999
This message is sent by the ControlNet Adapter Board and reads the
16-bit parameter data value for the parameter number selected.
PLC Block Transfer Instruction Data
PLC MSG Write instruction length: 3 words
PLC MSG Read instruction length: 4 words
Message Length
3
Header
Word 1 Header
Word 1
PLC Decimal Length
769
Parameter Number
PLC Decimal Value
769 –– Message OK
Parameter Value or
Status Word
Parameter Number
-31999 –– Message Error
Message Structure
Header
Word 2
Data
Word 3
Header
Word 2
Header
Word 3
Header
Word 4
0
PLC Request –– PLC Message Write
Drive Response –– PLC Message Read
Message Operation
The Parameter Value Read function specified in the PMW (PLC
MSG Write) reads a parameter value from the drive and places that
value (or an error code) in word 4 of the PMR (PLC MSG Read)
data file. The value shown is in device units.
If an error has occurred:
•
Word 2 of the PMR returns a value of -31999.
•
Word 4 contains the status code.
Parameter Read
Parameter Value Read