65
Checking Programs Section 2-3
Multi-word Operands Memory area boundaries are checked for multi-word operands for the pro-
gram check as shown in the following table.
2-3-3 Program Execution Check
Operand and instruction location checks are performed on instructions during
input from Programming Devices (including Programming Consoles) as well
as during program checks from Programming Devices (excluding Program-
ming Consoles). However, these are not final checks.
The following checks are performed during instruction execution.
Instruction Processing Errors
An instruction processing error will occur if incorrect data was provided when
executing an instruction or an attempt was made to execute an instruction out-
side of a task. Here, data required at the beginning of instruction processing
was checked and as a result, the instruction was not executed, the ER Flag
(Error Flag) will be turned ON and the EQ and N Flags may be retained or
turned OFF depending upon the instruction.
The ER Flag (error Flag) will turn OFF if the instruction (excluding input
instructions) ends normally. Conditions that turn ON the ER Flag will vary with
individual instructions. See descriptions of individual instructions in the CS/
CJ-series Programmable Controllers Programming Manual (W340) for more
details.
If Instruction Errors are set to Stop Operation in the PLC Setup, then opera-
tion will stop (fatal error) and the Instruction Processing Error Flag (A29508)
will turn ON if an instruction processing error occurs and the ER Flag turns
ON.
CX-Programmer Programming
Consoles
The following functionality is provided by the CX-Programmer
for multi-word operands that exceed a memory area boundary.
• The program cannot be transferred to the CPU Unit.
• The program also cannot be read from the CPU Unit.
• Compiling errors are generated for the program check.
• Warnings will appear on-screen during offline programming.
• Warnings will appear on-screen during online editing in
PROGRAM or MONITOR mode.
Checked when pro-
grams are input, i.e.,
operands that
exceed a memory
are boundary can-
not be written.
Type of error Flag that turns ON for error Stop/Continue operation
1.Instruction Processing Error ER Flag
The Instruction Processing Error Flag
(A29508) will also turn ON if Stop
Operation is specified when an error
occurs.
A setting in the PLC Setup can be used
to specify whether to stop or continue
operation for instruction processing
errors. The default is to continue opera-
tion.
A program error will be generated and
operation will stop only if Stop Opera-
tion is specified.
2.Access Error AER Flag
The Access Error Flag (A29510) will
turn ON if Stop Operation is specified
when an error occurs.
A setting in the PLC Setup can be used
to specify whether to stop or continue
operation for instruction processing
errors. The default is to continue opera-
tion.
A program error will be generated and
operation will stop only if Stop Opera-
tion is specified.
3.Illegal Instruction Error Illegal Instruction Error Flag (A29514) Fatal (program error)
4.UM (User Memory) Overflow Error UM Overflow Error Flag (A29515) Fatal (program error)
To Next Page
Loading...
Need help?
General
