Rockwell Automation 1336T Function Block Prog. Manual, Series A/B - Manual (Page 58)

3–10 System Interactions
1336 FORCE — 5.9 August 1995
Only one function block application is active within the drive at any
one time. However, multiple execution lists can be present in the
terminal devices attached to the drive. You can connect up to seven
terminal devices to the PLC Communications Adapter board, and
each terminal device can have its own copy of an execution list. In
addition, the DriveBlockEditor can even have multiple OFFLINE
execution lists in RAM or stored in the PCs hard drive.
Even though multiple execution lists can appear to be on the system,
only one function block application is active within the drive at any
one time. The drive’s execution list reflects what is currently
running. The only other execution list stored within the drive is a
copy in BRAM, which is used during BRAM recall or power up.
Terminal devices such as the DriveTools’ DriveBlockEditor and the
GPT maintain their own copies of the execution list. Because you
can initiate download and compile operations from any of the
terminal devices, do not initiate download and compile operations
from different terminal devices at the same time.
The drive uses a checksum value to differentiate between the running
application and the application stored in BRAM. If the checksum
values are the same, then the current application has not been
modified.
Understanding Multiple
Execution List Copies