Rockwell Automation 9323-S5500D A.I. SERIES MICROLOGIX 1000 AND PLC-500 SOFTW - Manual (Page 417)

Online Editing and Monitoring
18-7
Effects of Online Editing on Your System
This section covers the effects of online editing on your system. Keep these items in
mind while using the online editing function.
System Impacts
•
The scan time and interrupt latency can be extended up to 10 ms when accepting a
rung, assembling, or canceling edits. Use the following formula to calculate the
number of scans impacted:
10 +
# of rungs
50
+ # of ladder files (2-255) =
# of scans impacted
by an online edit
•
Processor memory is limited. Online editing can be performed until the program
area in the processor is exhausted.
•
The program execution time will be increased up to 117µs per edit rung. The
increased execution time occurs regardless of the current editing state. For
example, an “I/R” edit zone pair will impact the execution time of the program by
234µs.
Communication Break
If a communication break or other critical error occurs while the processor is receiving
online edit changes from PLC-500 A.I., an error message will appear and the software
will allow you to exit normally and save the project to disk. PLC-500 A.I. retains your
online editing changes in memory as well.
Data Table Files
Online editing cannot change the size of existing data tables nor can new ones be
created. Programming some ladder instructions, however, does cause data table values
to change. These instructions are those requiring timer, counter, and control addresses
to be specified.