Automatic control function programming manual ladder language

2.1.1.3 «System» I/O Card Refresh Task
Processing Performed
This task refreshes the card I/Os:
- read of %I. card inputs,
- write of %Q. card outputs,
- update of I/O card diagnostic variables.
2.1.1.4 «System» UNITE Server Task
Processing Performed
This task processes the UNITE requests sent to the automatic control function server.
Service Performed by the UNITE Server
The automatic control function server mainly processes the following UNITE requests:
- Read/write of variables (%I, %Q, %R, %W, %M, %V),
- load/unload of automatic control function tasks (%TS0, %SP30, etc.),
- automatic control function STOP (stopping of user tasks),
- automatic control function INIT (CPU intialisation),
- automatic control function RUN (running of user tasks).
2.1.2 «User» Tasks
2.1.2.1 Start up Task
Structure of an Application
The %INI task is called by the system before any other user tasks when the automatic control function is started.
This task can re-configure the I/O cards.
! CAUTION
The system reads the I/O card configuration returned by %INI. Any changes made later to
the configuration are ignored until the next restart.
2.1.2.2 Cyclic Tasks
The cyclic tasks are %TS0 to %TSn where n is incremented from 1 to 5 each RTC cycle.
The execution period of %TS0 is equal to an RTC cycle, i.e. 20 ms.
The execution period of %TS1, %TS2, %TS3 and %TS4 is equal to five RTC cycles, i.e. 100 ms (the fifth RTC cycle
is used by system task %TS5).
Tasks %TS are not interruptible:
- by occurrence of the RTC (1060 series I and series II multicard),
- by the IT set by parameter P99 (1060 series II - USCII).
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