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Bosch Rexroth AG
Introduction
PLCopen
IEC 61131
1.5.7
Function overview and system properties
General basic functions of the integrated PLC
–
A function can be called in textual languages as an operand used
in expressions.
–
A function has no "memory", i.e., the contents of variables are not
stored.
–
A function does not need an instance.
●
A function block has the following properties:
–
A function block can return several values.
–
A function block has a "memory", i.e., the contents of variables are
stored.
–
A function block requires an instance be specified.
●
Programs are globally known in the entire project. Programs are not in‐
stantiated. The variables of the program only exist once. Programs can
be called in a task. A task can call several programs and a program can
call functions, function blocks or other programs.
●
The boot project is a project loaded on the target (here a drive controller
from the "Rexroth IndraDrive" range with the functional firmware pack‐
age for "IndraMotion MLD") and started when booting up the drive con‐
troller depending on the setting (cf. "P-0-1367, PLC configuration").
PLCopen is an organization in which several manufacturers have collabora‐
ted to standardize programming interfaces, commissioning and maintenance,
and therefore harmonize programming access to motion control.
Independence from the control architecture is achieved by encapsulating
functionality and function block data, i.e., applications programmed according
to the standard developed by PLCopen ("PLCopen Motion Control Profile", a
set of IEC 61131-3 function blocks) are independent of the executing hard‐
ware and therefore can be reused beyond platform limits.
As is common in IEC 61131, libraries are provided with the IndraWorks
packages of "IndraMotion MLD". They contain ready-made functions, function
blocks and variables which are used as black boxes. There are two types of
libraries:
●
Firmware libraries: They do not contain any code, just declarations. The
code is hard coded in the firmware.
●
IEC libraries: They have been programmed in accordance with
IEC 61131-3 and, if required, their codes can be write- or read-protec‐
ted.
Freely programmable PLC in accordance with IEC 61131
By defining the industry standard for programming in automation,
IEC 61131-3 has for the first time established the basics of combined logic
and motion control. These are, in essence:
●
Defining the SFC (Sequential Function Chart) as a powerful program‐
ming tool for data flow-oriented programs, such as controllers
●
Defining the Pascal-esque ST (Structured Text) high-level language as
a powerful instrument even for programming complex (e.g., mathemati‐
cal) functionalities
LSA Control S.L. www.lsa-control.com comercial@lsa-control.com (+34) 960 62 43 01
DOK-INDRV*-MLD3-**VRS*-AP02-EN-P
Rexroth IndraDrive Rexroth IndraMotion MLD (2G) as of MPx-18
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