Elettrolinux

ClassicLadder is a type of programming language originally implemented on industrial PLC's (it's called LadderProgramming). It is based on the concept of relay contacts and coils, and can be used to construct logic checks and functions in a manner that is familiar to many systems integrators. But ClassicLadder is, also, a project to have a free ladder language in C. Generally, you find this type of language on PLC to make the programs; free ladder & sequential (grafcet) languages as used on many PLC for programming automation process. Ladder language allows to realize programs on PLC in an electric way. Modbus protocol for SCADA cnx and remote I/O modules. The following elements are available in the ladder:

• Booleans elements;
• Rising/Falling edges;
• Timers;
• Monostables, counters and compare of arithmetic expressions;
• ...and many other!

• Add a rung after the current rung;
• Insert a rung before the current rung;
• Modify the current rung;
• Delete the current rung.

It has support to the real time; RTLinux, RTAI, Xenomai and Comedi project.

           

OpenSCADA represents opened SCADA system constructed on principles of modules, multiplatform and scalability. (Supervisory Control And Data Acquisition) is the term which it is often used in sphere of automation of technological processes. The system OpenSCADA is intended for: acquisition, archiving, visualization of the information, delivery of operating influences, and also for other related operations, which are characteristic for full-function SCADA systems. The system OpenSCADA can be used:

• On industrial targets as full-function SCADA system;
• In built in (embedded) systems, as an environment of performance, including inside PLC (Programmed Logic Controllers);
• For construction of various models (technological, chemical, physical, electric processes);
• On personal computers, servers and clusters for acquisition, processing, representation and archiving of the information about system and its environment.

• Reliability: vast majority of servers and clusters works on GNU/Linux;
• Safety;
• Flexibility/Scalability: in view of the openness and modularity allows to build decisions under any requirements;
• Availability: owing to license GPL it is completely free system, and at high qualification of the user and free-of-charge;
• Popularity, development, support, prevalence (the system is actively developed by set of enthusiasts, firms and official bodies from all over the world, it gets greater and greater support in the user and corporate market, it is actively implemented into the state structures of the various countries).

As the system OpenSCADA is developed on standard of POSIX OS, by principles of mutiplatform its adaptation on other OS will not make a problem. Heart of system is the modular kernel. And depending on that, what modules are connected, system can to act both in a role of various servers, and in a role of various clients, and also to combine these functions in one program. It allows to work in practice client-server architecture of SCADA system on the basis of the same components/modules, saving thus: machine memory, disk space, and also valuable time of programmers. Modules of OpenSCADA system are stored in dynamic libraries. Each dynamic library can contain set of modules of various type. Filling of dynamic libraries by modules is determined by functional connectivity of modules. Dynamic libraries suppose hot replacement, that allows during functioning to update separate parts of system. The method of storage of a code of modules in dynamic libraries is the main for OpenSCADA as far as it is supported practically by all modern operational systems(OS). However it does not exclude an opportunity of development of other methods of storage of a code of modules. On the basis of modules the following functional parts of OpenSCADA system are realized:

• Databases;
• Archives (messages and values);
• Protocols of communication interfaces;
• Communication interfaces, transports;
• Sources of data and data acquisition;
• Iinterfaces of the user (GUI, TUI, WebGUI, speech, signal...);
• The additional and special modules.

Management of modules is carried out by a subsystem "Management of modules". Functions of a subsystem are: connection, switching-off, updating of modules, and also other operations connected with modules and libraries of modules. In total the OpenSCADA system contains 9 subsystems from them 7 subsystems are modular: 9 subsystems of the OpenSCADA system are basic and are present at any configuration. To the list of 9 subsystems new subsystems by means of modules can be added. Subsystems of the OpenSCADA system:

• Archives (modular);
• Databases (modular);
• Safety;
• Interfaces of the user (modular);
• Management of modules;
• Data acquisition (modular);
• Transport protocols (modular);
• Special (modular);
• Transports (modular).

For more information click here.

               

PLC's are real time controllers whose function is to periodically read inputs, run several real time tasks, and control outputs, in a steady time period. PLC's are the standard platform for automation applications, and can they can be programmed in one or more of the 4 programming languages as defined by IEC116131-3; Instruction List, Ladder Diagram, Function Block Diagram, or Structured Text. PLC-EMU emulates this function: in a configurable time cycle, it will read the inputs from your card, run a task as programmed by the user, and send the appropriate outputs back to the card. PLC-EMU stands for Programmable Logic Controller EMUlator, this means that PLC-EMU is a tool for emulating PLC's on a Linux box, using I/O cards. This way you can build a cheap alternative to PLC's, for use with automation applications; it consists of a text-based Ladder Diagram parser, a minimal C API and an optional ncurses-based interface for online control. You need to install one or more PCI/ISA digital I/O card (analog I/O not supported yet.); it works in two modes: through comedi, and in user space. In Comedi mode, all you need to do is install and set up the apropriate Comedi driver for your card, and copy the setup values to PLC-EMU's config file. For more informations, and download, click here.