4. INITIAL PROGRAMMING
4.2.2. Basic
In the Basic Project Profile, the application has one user task of the Continuous type called MainTask, which executes the
program in a continuous loop (with no definition of cycle time) with priority fixed in 13 (thirteen). This task is responsible
for the execution of a single programming unit POU called MainPrg. It’s important to notice that the cycle time may vary
according to the quantity of communication tasks used, as in this mode, the main task is interrupted by communication tasks.
This profile also allows the inclusion of two event tasks with higher priority, that can interrupt (preempt) the MainTask at
any given moment: the task named ExternInterruptTask00 is an event task of the External type with priority fixed in 02 (two);
the task named TimeInterruptTask00 is an event task of the Cyclic type with priority fixed as 01 (one).
The Basic project template model includes three tasks already completely defined as presented in table below. The devel-
oper need only to create the associated programs.
Tasks POU Priority Type Interval Event
MainTask MainPrg 13 Continuous - -
ExternInterruptTask00 ExternInterruptPrg00 02 External - IO_EVT_0
TimeInterruptTask00 TimeInterruptPrg00 01 Cyclic 20 ms -
Table 34: Basic Profile Tasks
4.2.3. Normal
In the Normal Project Profile, the application has one user task of the Cyclic type, called MainTask. This task is responsible
for the execution of a single programming unit POU called MainPrg. This program and this task are similar to the only task
and only program of the Single profile, but here the application can integrate additional user tasks. These other tasks, named
CyclicTask00 and CyclicTask01, each one responsible for the exclusive execution of its respective CyclicPrg<nn> program.
The CyclicTask<nn> tasks are always of the cyclic type and with priority fixed in 13 (thirteen), same priority as MainTask.
These two types form a group called basic tasks, which associated programs can call other POUs of the Program, Function and
Function Block types.
Furthermore, this profile can include event tasks with higher priority than the basic tasks, which can interrupt (preempt)
these tasks execution at any time.
The task called ExternInterruptTask00 is an event task of the External type which execution is triggered by some external
event, such as the variation of a control signal on a serial port or the variation of a digital input on the NEXTO bus. This
task priority is fixed in 02 (two), being responsible exclusively for the execution of the ExternInterruptPrg00 program. The
task called TimeInterruptTask00 is an event task of the Cyclic type with a priority fixed as 01 (one), being responsible for the
execution exclusively of TimeInterruptPrg00 program.
In the Normal project model, there are five tasks, and its POUs, already fully defines as shown in table below. The developer
needs only to implement the programs content, opting, on the wizard, for any of the languages in IEC 61131-3 standard. The
tasks interval and trigger events can be configured by the developer and the unnecessary tasks can be eliminated.
Tasks POU Priority Type Interval Event
MainTask MainPrg 13 Cyclic 20 ms -
CyclicTask00 CyclicPrg00 13 Cyclic 200 ms -
CyclicTask01 CyclicPrg01 13 Cyclic 500 ms -
ExternInterruptTask00 ExternInterruptPrg00 02 External - IO_EVT_0
TimeInterruptTask00 TimeInterruptPrg00 01 Cyclic 20 ms -
Table 35: Normal Profile Tasks
4.2.4. Expert
The Expert Project Profile includes the same basic tasks, CyclicTask<nn>, ExternInterruptTask00 and TimeInterruptTask00
with the same priorities (13, 02 and 01 respectively), but it’s an expansion from the previous ones, due to accept multiple events
tasks. That is, the application can include various ExternInterruptTask<nn> or TimeInterruptTask<nn> tasks that execute the
ExternInterruptPrg<nn> and TimeInterruptPrg<nn> programs. The additional event tasks priorities can be freely selected from
08 to 12. In this profile, besides the standard programs, each task can execute additional programs.
35
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