The T2550 is capable of both analog, logic and sequence control and is self-contained up to a capacity of 128 I/O points.

Larger systems may be implemented by interconnecting multiple T2550 units to form a distributed system where the ELIN peer to peer communications is used to the best advantage.

Alternative Ethernet and serial communications protocols are available to facilitate the simple connection to other equipment.

Large systems or complex sequence and batch applications are treated in a ‘layered’ fashion by decoupling front-end closed-loop control and its associated I/O and control modules (logical devices) from the main strategy, following the S88.01 standard for batch control. This is achieved by assigning the role of strategy coordination to the T2550 or the ‘short’ version of the T2550. This T2550, which uses the same processor as the standard controller has no I/O, it provides coordination and sequence control of the lower level elements.

The T2550 units are responsible for local control loops as well as interlocks and override logic, etc. The decoupling of front-end and co-ordination control facilitates strategy modification on a running plant, and changes to the Unit Supervisor (or even complete replacement) may be carried out without affecting the operation of loops in the T2550 Unit Controllers, which continue to be accessible from the workstations.

Using the T2550 as a redundant controller pair you no longer have to be concerned about controller or communications failure as your process is automatically protected. If external communications or field I/O communications to the active controller, or the active controller itself fails then the secondary controller automatically takes over, providing uninterrupted control and bump less transfer of the communications and process I/O. An alarm warns the operator that the changeover event has occurred.

Replacement of a processor for any reason can be done with the power on.

Commissioning of the redundant capable processor is simple, plug the second processor into a redundant base unit and press synchronize, all the rest is automatic. No special cabling is required.

The T2550 supports the level of block structuring normally only found in advanced DCS systems. The continuous strategy is built up by interconnection of function blocks from a rich library of analog and logic elements.

Sequences act in a supervisory role relative to the continuous database and may thus be loaded and unloaded independently. This is increasingly important for batch sequences, which relate to the process rather than the physical equipment, as these must be changed to meet the requirement of flexible plants. The capacity of the local filing system allows storage of a large number of sequences. Their operation is controlled through specialized blocks in the continuous database.

The ELIN control network is the backbone of the control and data acquisition network that provides peer-to-peer communications between control nodes and seamless access to all data by operator and configuration workstations.

All nodes appear as part of a coherent distributed database. The database in any networked element is accessible to any other network element, allowing complete flexibility in strategy interconnection.

ELIN supports OPC with a readily available server and direct connection of operator, configuration workstations and other Eurotherm control and logging units including the T800 Integrated Loop Processor where standalone or panel-mounted display and control is appropriate.

Connection to existing networks LIN networks via T225 ELIN – ALIN bridge.

At the heart of the system is the LINtools configuration and engineering station. LINtools is a comprehensive set of configuration, test, documentation and commissioning tools for strategy elements distributed over the LIN control backbone.

The LINtools suite includes graphical configuration of block structured continuous control, sequence control SFC’s, ladder and graphics for any LIN based product. VIEW and Online reconfiguration modes allows dynamic monitoring and editing of running databases and flow charts.

LINtools follows the IEC 61131-3 standard for sequence configuration, while adopting a decoupling of continuous and sequential strategy appropriate to complex process control.

Underlying the design of LINtools are the concepts of simplicity and productivity. Online help, free-format text annotation and area editing are just some of the features included not only to make LINtools easy to use in itself but also to make work done understandable and reusable. LINtools runs on a standalone or networked PC.

Languages appropriate for the I/O type and for the application

• Function Block Diagram
• Sequence Function Chart
• Structured Text
• Relay Ladder Logic Control

Control systems can be large and complex, they are expected to serve many needs and work well for long periods without shutdown under ever varying workloads, Online reconfiguration provides a useful foundation for enhancement of the deployed control system and allows modification of the systems application software after it has been deployed and is running.

With generic support for adding and hot swapping I/O. Online reconfiguration allows active strategy components to be modified, wrapped with additional functionality or replaced with a different implementation. This may be used the same or new I/O interfaces and any internally available variables.

You can tentatively add and delete, function blocks, wires, rungs elements steps and transitions to create a new or improved control strategy for your application while the process is running. You can then try and entry the strategy, ensuring it’s correct for your application before finally applying.

Continuous strategies are configured graphically on screen using ‘block structured’ techniques implemented across system.

The control configurator supports a comprehensive library of functions together with powerful editing and compound definition facilities. Merging allows the re-use of similar sections of databases avoiding duplication of effort. Free text may be placed on the screen or attached to function blocks, simplifying descriptive documentation. Context-sensitive help reduces the need to keep referring to manuals.

Sequences are configured graphically using Sequential Function Charts (SFCs) following the IEC 61131-3 standard. Steps initiate Actions which may be Structured Text statements (ST) or nested SFCs. Transitions determine when control passes from one step to the next. By accessing the continuous control strategy this configurator presents the available points through a menu system, eliminating the need to remember the names of points and reducing the likelihood of typing errors.

Like the control configurator this configurator supports text annotation and context-sensitive help.

ACTION blocks in the continuous control strategy have their functionality defined in Ladder diagram or Structured Text (ST) within a standard template. These are particularly appropriate for implementation of plant control modules. The configurator is used to generate reusable structured text definitions.

Action functionality can also be configured using ladder logic graphical tools

The instrument is capable of automatically creating its own LIN Database, including all necessary module and I/O Function Blocks based on the I/O detected in the Base Unit.

When the detection is complete, an operational database is created and runs automatically.

Automatic database creation is available from within LINtools when connected to a network containing T2550s.

Documentation and file utilities allow the strategy and graphics to be fully documented and transferred across the network.

Hard copy documentation consists of the graphical representation of the control strategy supplemented by a listing of the block parameters and connections. Output can be to a printer or in PostScript or AutoCAD compatible file format. User annotations may be added either directly to graphical screens, or associated with blocks and steps. In this way LINtools provides an electronic documentation environment.