Rockwell Automation 1336T ControlNet Frn1.02 Rev 1.5 - Manual (Page 53)

4–11 Using Unscheduled Messaging
Publication 1336 FORCE–5.18 ––March, 1999
The Continuous Parameter Value Read function reads a continuous
list of parameters beginning with the starting parameter number.
You define the number of parameters to be read.
PLC Block Transfer Instruction Data
PLC MSG Write instruction length: 4 words
PLC MSG Read instruction length: 5-64 words
Message Length
4
Header
Word 1 Header
Word 1
PLC Decimal Value
1
PLC Decimal Value
1 –– Message OK
-32767 –– Message Error
Number of Parameter
Values to Read
Starting Parameter
Number
Number of Parameter
Values to Read
Starting Parameter
Number
•
•
•
•
Data
Word 64
Message Structure
Header
Word 2
Data
Word 3
Data
Word 4
Header
Word 2
Data
Word 3
Data
Word 4
Data
Word 5
Data
Word 6
Data
Word 7
Value Number 1 or
Status Word
Value Number 2 or
Status Word
Value Number 3 or
Status Word
Value Number 60 or
Status Word
0
PLC Request –– PLC Message Write
Drive Response –– PLC Message Read
Message Operation
The Continuous Parameter Value Read function specified in the
PMW reads a consecutive group of parameter values from the
device, beginning with the starting parameter number defined in
word 4 of the PMW message. Word 3 of the PMW message defines
the number of parameters to be read. The values return in the PMR
response, beginning with word 5 of the message.
If an error has occurred in reading any of the values, the PMR
returns a status word with a negative value instead of the parameter
value.
Parameter Read
Continuous Parameter Value
Read