Omron CX-PROGRAMMER V8.1 Operation Manual page 151

Procedures
Note
Canceling Changes to Function Block Definitions
Effects on CPU Unit Operation
Maximum Cycle Time
Extensions for Online
Editing
Note
!Caution If synchronous unit operation is being used, an increase in the synchronous
Restrictions in Online Editing of Function Block Definitions
126
Source Code and Object Code
Before transferring a program, the CX-Programmer normally compiles the
source code into object code so that the CPU Unit can execute it and then
transfers both the source code and object code to the CPU Unit. The CPU
Unit stores the source code and object code in user memory and built-in flash
memory. Only when both the source code and object code exist in the CPU
Unit can the CX-Programmer transfer and restore the program for the upload
operation.
Select FB online Edit - Cancel to discard any changes made to a function
block definition. The function block definition will not be transferred to the CPU
Unit and the original definition will be restored.
The following will occur if online editing is performed with the CPU Unit oper-
ating in MONITOR mode: 1) The cycle time of the CPU Unit will be extended
by several cycle times when the program in the CPU Unit is rewritten and 2)
The cycle time will again be extended when the results of online editing are
backed up to built-in flash memory. (At this time, the BKUP indicator on the
front of the CPU Unit will flash and the progress will be displayed on the CX-
Programmer.)
The maximum extensions to the cycle time are given in the following table.
During online editing
12 ms max. 4% of cycle time
Cycle Time Monitor Time
Be sure that the cycle time monitor time set in the PLC Setup is not exceeded
when the program is rewritten as a result of online editing in MONITOR mode.
If the monitor time is exceeded, a cycle time exceeded error will occur and
CPU Unit operation will stop. If this occurs, switch to PROGRAM mode and
then to MONITOR or RUN mode to restart operation.
processing time caused by online editing may result in unexpected operation
timing. Perform online editing only after confirming that an increased synchro-
nous processing time will not affect the operation of the main and slave axes.
The following restrictions apply to online editing of function block definitions.
• For CJ2-series CPU Units, there is no restriction on the number of steps
that can be added to or deleted from a function block definition during one
online editing operation.
• Online editing is not possible for function block definitions that exceed
4 Ksteps. (except for CJ2-series CPU Units)
• A maximum of 0.5 Ksteps can be added to or deleted from a function
block definition during one online editing operation. (except for CJ2-series
CPU Units)
• Input variables, output variables, and input-output variables cannot be
added or deleted.
• New function block instances cannot be added.
• Instance names cannot be changed.
During backup
Section 3-2