Parameter write, Plc block transfer instruction data, Message operation – Rockwell Automation 1336T ControlNet Frn1.02 Rev 1.5 User Manual
Page 60: Example, Parameter value write
4–18
Using Unscheduled Messaging
Publication 1336 FORCE–5.18 ––March, 1999
This message sent by the PLC Communications Adapter Board reads
the 16-bit parameter data value for the parameter number selected.
PLC Block Transfer Instruction Data
PLC MSG Write instruction length:
4 words
PLC MSG Read instruction length:
4 words
Message Length
4
Header
Word 1
Header
Word 1
PLC Decimal Value
-31999
Header
Word 2
Parameter Number
Data
Word 3
PLC Decimal Value
769 –– Message OK
Header
Word 2
Data
Word 3
Parameter Number
-31999 –– Message Error
Data
Word 4
Parameter Value
Data
Word 4
Message Structure
0
PLC Request –– PLC Message Write
Parameter Value or
Status Word
Drive Response –– PLC Message Read
Message Operation
The Parameter Value Write function specified in the PMW sends a
new value (specified in word 4 of the PMW header message) to the
parameter specified in the PMW header word 3. The value must be
in device units.
If an error has occurred:
•
Word 2 of the response returns a value of -31999.
•
Word 4 contains a status code.
Example
In this example, a value of 4096 was sent to parameter 20. 4096 is in
drive units and indicates a value of 100% of rated drive volts as
defined by parameter 147, Drive Rated Volts.
1
0
N7:10
2
3
4
5
6
7
8
9
N7:90
PLC MSG
Write File
PLC MSG
Read File
Data Format
20
4096
20
4096
4
0
-31999
769
➀
➀
➀
➀
➀ These values vary depending on parameters and products.
Parameter Write
Parameter Value Write