10 CPU Unit Functions
10-76
CJ2 CPU Unit Software User’s Manual
The Error Flag (P_ER) will turn ON if instructions in the ladder program are outside the range for input
parameters. This flag can be referenced to check instruction errors when instructions are executed.
If the Stop CPU on Instruction Error Check Box is selected in PLC Setup, a program error will occur if
one of the following instruction errors occurs, and operation will be stopped. This function can be used
to check if an instruction error has occurred.
z Instruction Errors That Cause Program Errors (A295)
The stop position will be stored as described below when operation stops due to a program error.
z Program Error Task (A294)
It is possible to check what task the fatal error occurred in. When a fatal error is cleared, the Program
Error Task will be cleared.
z Program Error Position (A299: Upper Bytes, A298: Lower Bytes)
If execution is stopped due to a program error, the following program address for the stop position will
be stored.
Note The program address is valid only for ladder programs. It cannot be used with ST or SFC lan-
guage programs.
• Error in Ladder Program:
Address counting from the start of the ladder program
• Error in Ladder Action Program:
Address counting from the start of the ladder action program
• Error in Transition Program:
Address counting from the start of the transition program
• Error in Function Block
Address counting from the start of the function block program
10-7-7 Storing the Stop Position at Errors
Name Address Description
Instruction Processing
Error Flag
A295.08 This flag and the Error Flag (P_ER) will be turned ON when an instruc-
tion processing error has occurred and the PLC Setup has been set to
stop operation for an instruction error.
Indirect DM/EM BCD
Error Flag
A295.09 This flag will be turned ON when an indirect DM/EM BCD error has
occurred and the PLC Setup has been set to stop operation an indirect
DM/EM BCD error.
Illegal Access Error Flag A295.10 This flag will be turned ON when an illegal access error has occurred
(e.g., system area, R/W access to area converted to EM file, write
access to write-protected area, or indirect DM/EM BCD error).
Name Address Description
Program Error Task A294 Provides the type and number of the task that was being executed
when program execution stops as a result of a program error.
0000 to 007F hex (corresponding to tasks 0 to 127)
8000 to 80FF hex (corresponding to interrupt tasks 0 to 255, including
extra cyclic tasks)
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