Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 137)

Publication AG-UM008C-EN-P - February 2005
Configuring MicroLogix 1100/1200/1500 Controllers 3-69
Controller Responds with Reply
If the data integrity check fails, the record is deleted and an error is
sent with STS of 0xF0 and ext STS of 0x0E.
For more information on writing a DF1 protocol, refer to
Allen-Bradley publication 1770-RM516, DF1 Protocol and Command
Set Reference Manual (available from
www.theautomationbookstore.com).
Conditions that Will Erase
the Data Retrieval File
The following conditions will cause previously logged data to be lost:
•
Program download from RSLogix 500 to controller.
•
Memory Module transfer to controller except for Memory
Module autoload of the same program.
•
Full Queue - when a queue is full, new records are recorded
over the existing records, starting at the beginning of the file.
You can put the following rung in your ladder program to
prevent this from happening:
Table 3.17 Reply Structure
SRC DST CMD 4f STS TNS DATA EXT STS
Field Function Description
SRC Source Node
DST Destination Node
CMD Command Code
STS Status Code
TNS Transaction Number Always 2 bytes
DATA Formatted string
IMPORTANT
The data in the retrieval file can only be read once.
Then it is erased from the processor.
B3:1
1
LEQ
Less Than or Eql (A<=B)
Source A
DLS0:5.RST
Source B
DLS0:5.FSZ
LEQ DLG
Data Log
queue number
5
DLG