Blocking Errors

General

Blocking errors, caused by the application program, do not cause system errors but prohibit execution of the program. When such an error occurs, the PLC stops immediately and goes into HALT mode (all tasks are stopped on the current instruction). The ERR LED flashes.

Restarting of the Application After a Blocking Error

To end this status it is necessary to init the PLC or to set the %S0 bit to 1.

The application is then in an initial state:

The data resumes its initial value.
Tasks are stopped at end of cycle.
The input image is refreshed.
Outputs are controlled in fallback position.

The RUN command then allows the application to be restarted.

Blocking Error Diagnosis

Indication of a blocking error is signaled by the ERR and RUN LEDs flashing on the processor front panel.

The system words %SW126 and %SW127 indicate the address of the instruction which caused the blocking error.

The nature of the error is indicated by the system word %SW125.

The following table presents the errors signaled by the values of the system word %SW125.

Hexadecimal Value of %SW125	Corresponding Error
23•••	Execution of a CALL function towards an undefined subroutine
0•••	Execution of an unknown function
2258	Execution of the HALT instruction
9690	Failure of the application CRC check (checksum)
DEB0	Watchdog overrun
DE87	Calculation error on numbers with decimal points
DEF0	Division by 0
DEF1	Character string transfer error
DEF2	Capacity exceeded
DEF3	Index overrun
DEF7	SFC execution error
DEFE	SFC steps undefined
81F4	SFC node incorrect
82F4	SFC code inaccessible
83F4	SFC work space inaccessible
84F4	Too many initial SFC steps
85F4	Too many active SFC steps
86F4	SFC sequence code incorrect
87F4	SFC code description incorrect
88F4	SFC reference table incorrect
89F4	SFC internal index calculation error
8AF4	SFC step status not available
8BF4	SFC memory too small after a change due to a download
8CF4	Transition/action section inaccessible
8DF4	SFC work space too small
8EF4	Version of the SFC code older than the interpreter
8FF4	Version of the SFC code more recent than the interpreter
90F4	Poor description of a SFC object: NULL pointer
91F4	Illegal action identifier
92F4	Poor definition of the time for an action identifier
93F4	Macro step cannot be found in the list of active steps for deactivation
94F4	Overflow in the action table
95F4	Overflow in the step activation/deactivation table