The Multi-Task System
124
Operating Manual XCA 1100 / XCA 1200
●
Version 12/17
9.2.3
System tasks
System tasks and system programs (SPGs) are started automatically
by the operating system when an event occurs in connection with the
operating system. The SPGs which can be used are listed in the
following table:
No.
Name
Event
Actions
SPG 0
WARM_START
Is executed during a warm
start
Retentive data is not initialised
Non-buffered data is initialized
The open function of the I/O driver is
executed
User tasks are activated
PLC switches to run status
SPG 1
COLD_START
Is executed during a cold start
All data is initialised
The open function of the I/O driver is
executed
User tasks are activated
PLC switches to run status
SPG 2
TO_STOP
Is executed when program
execution is stopped
User tasks are deactivated
All outputs are updated
The close function of the I/O driver is
executed
PLC switches to STOP
SPG 10
WATCHDOG
Is executed when a task has
not been completed within its
watchdog time
User tasks are deactivated
All outputs are updated
The close function of the I/O driver is
executed
PLC switches to STOP
SPG 11
ZERODIV
Is executed if division by zero
occurs during program
execution
User tasks are deactivated
All outputs are updated
The close function of the I/O driver is
executed
PLC switches to STOP
SPG 12
STACKOVER
Is executed if a stack overflow
has occurred. Is only executed
if the “Stack-Prüfung” [“Stack
check”] checkbox in the
“Ressource ... einrichten”
[Resource ... Set up] dialog in
MULTIPROG was activated.
User tasks are deactivated
All outputs are updated
The close function of the I/O driver is
executed
PLC switches to STOP
SPG 13
BADCAL
Is executed if a non-existent
manufacturer-specific POU is
called
User tasks are deactivated
All outputs are updated
The close function of the I/O driver is
executed
PLC switches to STOP
SPG 14
IOERROR
Is executed if an error occurs
in the I/O driver while the
process is running
PLC continues execution
SPG 16
MATHERR
Is executed if a sliding point
error occurs in an arithmetic
function
User tasks are deactivated
All outputs are updated
The close function of the I/O driver is
executed
PLC switches to STOP