Introduction

Blocking conditions caused during the execution of the safety or the process program result from either the detection of system errors, or of the HALT state of a task in which the error was detected.

NOTE: The M580 safety PAC presents two independent HALT states:

  • Process HALT applies to the non-SAFE tasks (MAST, FAST, AUX0, and AUX1). When any process task enters the HALT state, all other process tasks also enter the HALT state.

  • SAFE HALT applies only to the SAFE task.

Refer to the M580 Safety PAC Operating States topic for a description of the HALT and STOP states.

Diagnostics

When the CPU detects a blocking condition causing a system error, a description of the detected error is provided in system word %SW124.

When the CPU detects a blocking condition causing a HALT state, a description of the detected error is provided in system word %SW125.

%SW124 system word values and corresponding blocking condition description:

%SW124 Value (hex)

Blocking Condition Description

5AF2

RAM detected error in memory check

5AFB

Safety firmware code error detected

5AF6

Safety watchdog overrun detected on CPU

5AFF

Safety watchdog overrun detected on Coprocessor

5B01

Coprocessor not detected at startup

%SW125 system word values and corresponding blocking condition description:

%SW125 Value (hex)

Blocking Condition Description

0•••

execution of an unknown function

0002

SD card signature feature (used with SIG_CHECK and SIG_WRITE functions)

2258

execution of the HALT instruction

2259

execution flow different than the reference flow

23••

execution of a CALL function towards an undefined subroutine

5AF3

comparison error detected by CPU

5AF9

instruction error detected at start-up or runtime

5AFA

comparison error detected on CRC value

5AFC

comparison error detected by coprocessor

5AFD

internal error detected by coprocessor; sub-code in %SW126: 1 (unknown result), 2 (CRC application), 7 (incorrect activity counter)

5AFE

Copro synchronization error detected - CPU only; sub-code in %SW126: 3 (diagnostic), 4 (end UL), 5 (comparison), 6 (BC out), 8 (HALT during UL), 9 HALT during comparison), 10 (HALT during BC out).

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 detected 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 an SFC object: NULL pointer

91F4

action identifier not authorized

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

9690

error detected in the application CRC check (checksum)

DE87

calculation detected floating point error

DEB0

task watchdog overrun (%S11 and %S19 are set)

DEF0

division by 0

DEF1

character string transfer detected error

DEF2

capacity exceeded

DEF3

index overrun

DEF4

inconsistent task periods

DEF7

SFC execution detected error

DEFE

SFC steps undefined

Restarting the Application

After a blocking condition has occurred, the halted tasks need to be initialized. If the HALT occurred for a:

  • process task (MAST, FAST, AUX0, or AUX1), initialization is performed by either the Control Expert PLC > Init command or by setting the %S0 bit to 1.

  • SAFE task, initialization is performed by the Control Expert PLC > Init Safety command.

When initialized, the application behaves as follows:

  • the data resume their 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 or tasks to be restarted.