Trend file, Plc block transfer instruction data, Message operation – Rockwell Automation 1336T ControlNet Frn1.02 Rev 1.5 User Manual
Page 104: Example, Maximum trend size available
4–62
Using Unscheduled Messaging
Publication 1336 FORCE–5.18 ––March, 1999
The Maximum Trend Size Available function allows you to
determine the size of the trend buffer. This function always returns
500.
PLC Block Transfer Instruction Data
PLC Message Write instruction length:
3 words
PLC Message Read instruction length:
3 words
Header
Word 1
Header
Word 1
Header
Word 2
Header
Word 2
Header
Word 3
Maximum Trend Size
Message Structure
Header
Word 3
0
PLC Decimal Value
4097
PLC Decimal Value
4097 –– Message OK
–28671 –– Message Error
Message Length
3
Message Length
3
PLC Request –– PLC Message Write
Drive Response –– PLC Message Read
Message Operation
You can use the Maximum Trend Size Available function to
determine the size of the trend buffer. This function always returns
500.
Example
In this example, a Maximum Trend Size Available request was sent
to the drive. The drive returned a value of 500 in word 3.
1
0
N7:10
2
3
4
5
6
7
8
9
N7:90
PLC MSG
Write File
PLC MSG
Read File
Data Format
0
500
3
3
4097
4097
Trend File
Maximum Trend Size Available