大家好:
我是一名计算机专业的研究生,但跟的导师是工业控制方向的.导师的公司主要用plc和rtu做一些工程,硬件比较强.现在能够自己直接做出rtu等来,不过软件没什么人做.所以他让我看看61131-3以及rtos的东西,看看能不能以后自己开发一些类似的控制软件和编译器.
我觉得这个课题是不是太大了?还有我好象没怎么看见在国内有61131之类的人才需求.
各位前辈可以帮我分析一下吗?
谢谢!
欧美PLC多符合IEC61131-3标准。
所以，你的选择非常有前途。如你有兴趣，可以尝试作SoftPLC(当然要符合国际标准，不然没有人会学你独创的语言、语法，从而给推广带来难度)。
所以，你的选择非常有前途。如你有兴趣，可以尝试作SoftPLC(当然要符合国际标准，不然没有人会学你独创的语言、语法，从而给推广带来难度)。
04-10-31 18:36
不错，已经开始有人作“核”了，中国的工控界，属于自己的核心技术（包括软件与硬件），太少了。当然，军工不太了解，普通工业与民用属于前沿技术或核心技术的国货，太少了。普遍的是应用，业界里面的精英们，应用水平还是蛮高的。
04-10-31 19:38
What is IEC 1131?
The standard IEC 1131 has been established to standardize the multiple languages, sets of instructions and different concepts existing in the field of automation systems. The great variety of PLC concepts has led to an incompatibility between the different PLC platforms and manufacturers. The result was a great effort to be made for training, hard- and software investments.
IEC 1131 standardizes the programming languages, the interfaces between PLC and programming system, the sets of instructions and the handling and structuring of projects. The advantage of using IEC 1131 conform PLCs and programming systems is a portability of all platforms and the use of same concepts reducing costs for automation systems.
The standard consists of several parts and technical reports. The third part of the standard is dedicated to programming languages.
Obviously this standard has a great influence on the concept, structure, features and the handling of a programming system and the way to program a PLC.
The main changes that have come with IEC 1131-3 are:
Declaration of variables is similar to the variable declaration in higher programming languages.
Declaration of data types is possible.
Global and local data can be differentiated.
Programming means symbolic programming.
The standard IEC 1131 has been established to standardize the multiple languages, sets of instructions and different concepts existing in the field of automation systems. The great variety of PLC concepts has led to an incompatibility between the different PLC platforms and manufacturers. The result was a great effort to be made for training, hard- and software investments.
IEC 1131 standardizes the programming languages, the interfaces between PLC and programming system, the sets of instructions and the handling and structuring of projects. The advantage of using IEC 1131 conform PLCs and programming systems is a portability of all platforms and the use of same concepts reducing costs for automation systems.
The standard consists of several parts and technical reports. The third part of the standard is dedicated to programming languages.
Obviously this standard has a great influence on the concept, structure, features and the handling of a programming system and the way to program a PLC.
The main changes that have come with IEC 1131-3 are:
Declaration of variables is similar to the variable declaration in higher programming languages.
Declaration of data types is possible.
Global and local data can be differentiated.
Programming means symbolic programming.
04-11-03 19:55
Configuration elements in IEC 1131-3
An IEC 1131-3 conform PLC programming system reflects the hardware structure with the configuration elements. These configuration elements are basically configurations, resources and tasks.
Configurations in IEC 1131-3
A configuration can be compared to a programmable controller system, e.g. a rack. In a configuration one or several resources can be defined.
Resources in IEC 1131-3
A resource can be compared to a CPU which can be inserted in the rack. In a resource global variables can be declared, which are only valid within this resource. In a resource one or several tasks can be executed.
Tasks in IEC 1131-3
Tasks determine the time scheduling of the programs associated with them. This means that programs have to be associated to tasks. The settings of the task determine the time scheduling.
IEC 1131-3 describes different time scheduling models which results in three different task types:
Cyclic tasks are activated in a certain time interval and the program is executed periodically.
System tasks are called automatically by the PLC operating system if an error or a change of the operational state of the PLC occurs. They are also known as system programs or SPGs.
Event or interrupt tasks are activated if a certain event has happened.
Each task has a certain priority. In so called preemptive scheduling systems, an active task with low priority is interrupted immediately, when a task with higher priority becomes active due to a certain event. In systems with non-preemptive scheduling, task interruptions by tasks with higher priority are not possible.
The supported task types depend on the used PLC.
An IEC 1131-3 conform PLC programming system reflects the hardware structure with the configuration elements. These configuration elements are basically configurations, resources and tasks.
Configurations in IEC 1131-3
A configuration can be compared to a programmable controller system, e.g. a rack. In a configuration one or several resources can be defined.
Resources in IEC 1131-3
A resource can be compared to a CPU which can be inserted in the rack. In a resource global variables can be declared, which are only valid within this resource. In a resource one or several tasks can be executed.
Tasks in IEC 1131-3
Tasks determine the time scheduling of the programs associated with them. This means that programs have to be associated to tasks. The settings of the task determine the time scheduling.
IEC 1131-3 describes different time scheduling models which results in three different task types:
Cyclic tasks are activated in a certain time interval and the program is executed periodically.
System tasks are called automatically by the PLC operating system if an error or a change of the operational state of the PLC occurs. They are also known as system programs or SPGs.
Event or interrupt tasks are activated if a certain event has happened.
Each task has a certain priority. In so called preemptive scheduling systems, an active task with low priority is interrupted immediately, when a task with higher priority becomes active due to a certain event. In systems with non-preemptive scheduling, task interruptions by tasks with higher priority are not possible.
The supported task types depend on the used PLC.
04-11-03 19:56
POUs in IEC 1131-3
Program organization units or POUs are the language elements of a PLC program. They are small, independent software units containing the program code. The name of a POU should be unique within the project.
In IEC 1131-3 three types of POUs are distinguished referring to their different use:
programs
function blocks
functions
Each POU consists of two different parts: The declaration part and the code body part.
In the declaration part all necessary variables are declared.
The instruction or code body part of a POU is the part in which the instructions are programmed in the desired programming language.
Program organization units or POUs are the language elements of a PLC program. They are small, independent software units containing the program code. The name of a POU should be unique within the project.
In IEC 1131-3 three types of POUs are distinguished referring to their different use:
programs
function blocks
functions
Each POU consists of two different parts: The declaration part and the code body part.
In the declaration part all necessary variables are declared.
The instruction or code body part of a POU is the part in which the instructions are programmed in the desired programming language.
04-11-03 19:56