Installation manual

5/8
5
Software structure
Modicon TSX Micro
automation platform 0
PL7 Micro/Junior/Pro programming software
PL7 Micro/Junior/Pro software offers two types of structure:
b Single task: this is the simplified structure offered by default, where a single master
task consisting of a main program, comprising several sections and subroutines, is
executed.
b Multitask: this structure, which is better suited to high-performance real-time
applications, consists of a master task, a fast task and event-triggered tasks, which
have the highest priority. Master and fast tasks are divided into sections.
PL7 program tasks comprise several parts called sections and subroutines. Each
section can be programmed in the appropriate language for the processing to be
carried out.
Such division into sections enables a structured program to be created and program
modules can easily be generated or added.
Subroutines can be called from any section of the task to which they belong or from
other subroutines in the same task.
There are two types of cyclic execution:
b Normal cyclic execution. This is the default option.
b Periodic execution. This type of execution, as well as the period, are selected by
the user during configuration.
At the end of each scan, the PLC system launches the execution of a new scan.
The execution time of each scan is monitored by a software watchdog whose value
is defined by the user.
In the event of overrun, a fault occurs causing:
b The scan to stop immediately (STOP).
b A display on the front panel of the PLC.
b The alarm relay of the main rack power supply to be set to 0.
A new scan is executed at the end of each period. The execution time of the scan must
be less than the time of the period defined (1 to 255 ms). In the event of overrun, the
latter is stored in a system bit (%S19), which can be set to 0 by the user (by program
or by the terminal).
A software watchdog which can be configured by the user monitors the scan time. In
the event of overrun, an execution fault is signaled (see normal execution).
Software structure
Structured and modular programming
M
ast
Sas(LD)
PRE(LD)
Furnace_1(Grafcet)
CHART
POST(IL)
Cleaning(ST)
SR0
SR0
Alarm_Cleaning(ST)
Alarm_Furnace(ST)
Safety_Mon(LD)
Fast
Alarm_Sas(LD)
Simple task software structure
Normal execution (cyclic)
RUN STOP
Program
processing
Input acquisition
(%I)
Internal
processing
Update of
outputs (%O)
Periodic execution
Launch
of the period
Input acquisition
(%I)
RUN STOP
Program
processing
Update of
outputs (%O)
Internal
processing
End of period
P
resentation:
p
age 5/5
Functions:
pages 5/12 to 5/15
Characteristics:
pages 5/16 to 5/18
Reference:
pages 5/18 to 5/19
Courtesy of Steven Engineering, Inc. ● 230 Ryan Way, South San Francisco, CA 94080-6370 ● General Inquiries: [phone] ● www.stevenengineering.com
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