Automatic control function programming manual ladder language

2.2 Structure of an Application
Structure of an Application
An application includes a set of modules created under the PLCTOOL programming tool and loaded onto the NC to
control the system.
Detail of Modules
Ladder Task Modules
Ladder task modules are associated with:
- task %INI,
- tasks %TS0 to %TS4,
- tasks %TF0 to %TF15,
- tasks %TH0 to %TH15.
These modules are called by the system task manager. They cannot be called explicitly. The user manages these
task modules by means of the task management functions (see Chapter 7).
Ladder task modules are files of the *.XLA type.
Ladder subroutine modules
Ladder subroutine modules are associated with tasks %SP0 to %SP255 . These modules can be called from a task
module or another subroutine module using function sp(..) or spy(..).
A PLC subroutine written in Ladder language and called by the SP function from a C module must not include ANY
function calls (except functions goto 0 and call 0).
Ladder subroutine modules are files of the *.XLA type.
Executable Modules
Executable modules are produced by a C compiler (MCC68K). These modules can be called from a ladder task module
or a ladder subroutine module using function exec(..).
All tasks can be written in C. If the same task is written in C and in ladder language, it is the C code that is executed
by the automatic control function.
Executable modules are files of the *.XCX type.
Note on Initialising a C Module (.XCX)
Implementation of global memory code in the local PLC memory.
Execution of the following directives in the «main()»:
- Import(),
- Export(),
- Possible initialisation of certain variable types: global C variables of the XCX module, uninitialised variables (saved)
of Ladder language.
Resolution of imports/exports (imported variables cannot be used in the «main()»)
Initialisation of initialised Ladder variables
Execution of %INI module
Normal PLC cycle start.
REMARK On a PLC Stop/Start (without INIT), only the last three steps are executed.
The saved variables are %M, %C, %CQ; the initialised variables are %I, %Q, %R, %T,
%TQ, %V. The so-called «pulse» variables %W are reset by the RESET or power
off button.
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