Rockwell Automation 1785-Lxxx Enhanced and Ethernet PLC-5 Programmable Controllers - Manual (Page 299)

Publication 1785-UM012D-EN-P - July 2005
Maximizing System Performance C-13
The amount of time that the messaging and block-transfers can be delayed is
proportional to the size (K words) of the ladder file. The following table
lists the performance effects (when using any of the 6200 Series PLC-5
Programming Software releases that support the controller you are using).
You should re-design your programs to avoid possible communication pauses
if you currently:
• use large ladder logic program files
• have time critical remote block-transfers and/or serial, DH+, and
channel 3A messages
• must edit the program online during run mode
For best controller performance, segment your program files by using modular
programming design practices, such as main control programs (MCPs),
sequential function charts (SFCs), and the jump to subroutine (JSR)
instruction.
Effect of Inserting
Ladder Rungs at the
56K-word Limit Performing run-time or program-mode editing of ladder files that approach
the maximum program file size of 57,344 words could:
• prevent the rung from being inserted
• cause suspension of the operation by 6200 Series PLC-5 Programming
Software (release 4.3 and later)
To avoid or correct this problem, segment your program file using modular
programming, such as main control programs (MCPs), sequential function
charts (SFCs), and the jump to subroutine (JSR) instruction.
If you cannot segment your program file, save the file often while editing it.
If you encounter the error
Memory Unavailable for Attempted
Operation
, then clear controller memory.
Effected Data
Transfers Online Operations via any DH+ Channel:
Perform a Page Up/Page
Down at the End of a
Program File Insert/Delete Ladder
Rungs
Remote block-transfers 20 ms/K words 50 ms/Kwords
DH+ messages 20 ms/K words 50 ms/Kwords
Serial port messages 200 ms/K words 50 ms/Kwords
Channel 3A messages no impact 50 ms/Kwords
This consideration applies to PLC-5/60,
-5/60L, -5/80, and -5/80E controllers
when you are editing a program file that
approaches the maximum file limit of
57,344 words.