Many new features in the PLC
One of the most important new features for regular machine programming is incremental compilation of a PLC program. Only changes to the program are compiled, and are loaded into the controller by "online change". This makes the process of compiling and running a changed program much quicker. The declaration sections for the individual blocks and the global variable lists are precompiled at the editing stage. Since only code that is actually referenced is loaded into the controller, the memory requirement for executable code is reduced. Smaller memory requirements for code and memory optimization in TwinCAT Version 2.8 symbol manager is very important for the memory sensitive Bus Terminal Controllers and the PLC Box modules. All the source code information can now be stored together with the executable compiled code (boot project). This makes it possible to load the project from the controller.

The free, graphical Control Function Chart (CFC) editor has benefited from the addition of macro facilities. This allows a number of blocks to be grouped together. This can be done in several hierarchical levels, so that the program code becomes much easier to understand. Full support of monitoring, break points and program check are also new to CFC.

Single step operation has been integrated as an additional commissioning tool into the sequential function chart (SFC). It is possible here to follow a bit from one step to the next, independently of transitions. In the case of problems at the machine or equipment, it is often interesting to know which bit in a combination of Boolean signals has caused an output not to operate. Criterion analysis can help here: it traces back to find the root cause of a problem, and makes it available in a string. This string can easily be displayed in the visualization system, and helps the maintenance personnel to find the fault in the process quickly - they do not have to understand the PLC program.

TwinCAT 2.8 now makes it possible to adapt the complete PLC program with comments, symbols etc. in the local language. This means that local service personnel can work in their own language. To do this, all comments, variable names, string constants and folder names are specially exported to an ASCII file. Following translation, this file can be imported again.

It is also possible to compare two PLC programs by means of a project comparison. Detailed differences are displayed, and can be transferred from one project to another. All IEC languages, including graphical languages such as SFC and CFC, are supported.

Libraries for building automation and Motion Control
The TcPlcUtilities PLC library has had a number of conversion functions (BCD_to_INT, DEG_to_RAD etc.) added. For building automation applications, functions for the control of lights, roller blinds and for temperature controls have been provided in a library. The Motion Control blocks, standardized in the context of PLCopen, have been implemented as a TwinCAT library. This provides a simple, flexible, manufacturer-independent set of blocks available for control tasks extending from simple axis movements up to complex multi-axis movements.

There are also innovations in the PLC development environment: The help system for the development environment is now directly linked to the already familiar TwinCAT Information System. This makes sure that the help is always up-to-date. Many points related to operations in the PLC development environment have also been improved. The IntelliMouse is supported, and accessibility is structured. If a block is inserted, the list displayed is no longer simply linear, but a structured list of all libraries and every folder is shown. All the graphical IEC editors now offer continuously adjustable levels of zoom. If allocated addresses are used, it is now possible to carry out a check for address overlaps. The compiler then reports these as warnings. A further new feature is that the complete list of all the variables and all the data types used in a project are now stored in an XML file. The System Manager and the OPC Server access this file.

TwinCAT NC - when the slave becomes a master
In the axis coupling field, more flexibility has been provided to the treatment of axes following decoupling. If a slave is released from a master-slave relationship, it can continue without interruption as a fully functional master. A new end position and a new velocity can be specified once it has been uncoupled.

For single axis it is now possible to have more than one encoder and more than one controller per axis. This can be switched over by the PLC. This makes it possible to implement a changeover from, for instance position control to torque control using different encoders. For special requirements it is also possible to substitute an application-specific set value generator in the PLC for the existing set value generator.

The System Manager - hands-off management
The System Manager now provides COM interfaces for the automatic generation of TwinCAT system configurations. This allows machine-specific configurations to be created and existing configurations to be modified. Script languages (VBScript, JavaScript) can also use the interfaces. XML export/input of devices, boxes etc., is also possible. The export/import files are in XML format, and can be edited in any XML editor of choice.

The BK9500 USB Bus Coupler and the CP9035 Control Panel PCI card are now supported by TwinCAT. Automatic address assignment for PLC variables is also new in the System Manager. The time-consuming assignment of fixed I/O addresses to variables is no longer necessary. The variables are created with a wild card address, and the System Manager generates an optimized address on to which they are mapped. It is of course, nevertheless, possible to assign addresses manually.

New in TwinCAT OPC
The Beckhoff TwinCAT OPC Server is now available in Version 4.0. As well as Data Access 1 and 2 it now supports the OPC Alarm & Event 1.0 specification. The server is parameterized by auto-configuration through a link from PLC projects, or by uploading the symbols. This means that data exchange can take place with variables in all TwinCAT ADS devices: TwinCAT I/O, TwinCAT CP, TwinCAT CAM, TwinCAT NC, TwinCAT PLC runtime systems, Bus Terminal Controllers and PLC Box Modules. XML is used again here: namespace, eventspace, simulation signals and conversions can be configured by means of an XML file.

XML for data maintenance
XML is steadily turning into the standard language for data descriptions in IT circles. TwinCAT supports XML from the moment the system starts up. All the initialization data necessary for TwinCAT to start is provided in an XML file. This means that a TwinCAT configuration can be passed from one controller to the next by transferring this file. There are also other components in the TwinCAT system - the Eventlogger - that understand XML. The TwinCAT Eventlogger can display and manage messages from the system and from the PLC. The messages have classes and priorities, and may require acknowledgement. Preparing the messages for display as text (conversion to the local language, colours etc.) is carried out by what is known as the formatter. This obtains its own configuration and that of the messages from an XML file.

If needed - send an SMS
The new TwinCAT SMS Server allows an SMS to be sent to a mobile phone from the PLC. A server is offered for this purpose having a COM interface on one side, but which can also be addressed on the other side by the PLC via ADS. A PLC library for use with the Bus Terminal Controller is also offered for this purpose. As well as sending an SMS, it is possible to establish a modem connection from one GSM device to another GSM device in order to transfer user-specific data.

TwinCAT and Windows XP