TwinCAT System Overview


Overview 1:

The TwinCAT software system is a complete automation system for PC-compatible computers, which is referred to as "The Windows Control and Automation Technology": 

TwinCAT transforms every compatible PC into a real time control with multi-PLC, NC axis control, a programming environment and a control station.

TwinCAT substitutes PLC and NC controllers as well as control stations with:

TwinCAT unites the real time control capability with the open and world-wide largest software platform of Microsoft's Windows operating systems.

TwinCAT components

TwinCAT embraces a large number of system components which, together, constitute a complete solution for automation tasks:

Overview 2:

Programming of PLC programs for sequential logic in conformity with IEC61131-3,

Overview 3:  Overview 4:

Programming of NC point-to-point (PTP) and interpolation (I) positioning in conformity with DIN66025,

Overview 5:

Real time system for the execution of PLC and NC programs in an exactly timed (deterministic) fashion, regardless of how the PC is used for further tasks,

Overview 6:

I/O linking for all widespread field buses and the PC interfaces and also for third-party interface cards,

Overview 7:

Programming and data link with Windows applications ranging from visualisation to spreadsheet applications using OCX or DLL

TwinCAT real time system: Real time expansion for Windows NT

Overview 8:

TwinCAT features a real time expansion for Windows NT for the execution of automation programs in cycles as from 1 ms timed deterministically exact with a very small timing fluctuation (jitter) of only a few microseconds. The TwinCAT real time expansion is a multitasking environment for the exactly timed control of "servers" that handle a very diverse range of tasks such as PLC, NC, PID and cam switching mechanisms etc. TwinCAT is integrated in Windows NT and, during the run time, it adds real time functions to it that are not intrinsically available in NT. The user does not modify NT for the operation of TwinCAT, i.e. it can be purchased, installed, used and maintained in the usual fashion. All properties of Windows NT are available without change during the operation of TwinCAT. The computing capacity that TwinCAT demands of the computer for real time tasks can be limited. This setting remains fixed under all circumstances. A load display facilitates adjustment for the user.

TwinCAT IEC61131-3 programming based on a manufacturer-independent standard

Overview 9:

"TwinCAT PLC Control" is the programming environment for the PLC (PLC server) in the system: a powerful 32-bit programming environment for programs whose code size and data areas far exceed the possibilities of conventional PLC systems. TwinCAT PLC offers all languages defined in the IEC61131-3 standard. The programming environment makes it easy for programmers of conventional PLC systems to become acquainted with IEC61131-3 through the use of support tools. Its "object-oriented" structure suppresses side effects during analysis (online status display). Program and data changes are executed online in any code and the detection and remedying of errors (debugging) are supported with a very powerful link to the run time systems (servers) which, incidentally, is also network-compatible. Programs are compiled for PC and additionally for a number of mini PLC-hardware. All usual characteristics of a PLC are available.

TwinCAT PLC Server: up to 4 PLCs on one PC

The PLC server processes programs at fixed cycle times. TwinCAT starts the tasks of the run time systems in a deterministic fashion, i.e. up to 4 PLC run time systems can be run simultaneously on one PC. The run time systems, in turn, have multitasking abilities with 4 tasks each. Therefore, the PLC server offers 16 tasks in 4 run time systems, each task with its own priority and cycle time. In total, up to 32 Mbytes of program and 4 Mbytes of data can be used. The execution time on PC processors is extremely fast. I/O data is organised by the System Manager. Start and stop behaviour are identical to that of a "hardware" PLC (which, as we know, is also operated with software). PLC booting on PC startup and remanent data are supported; while Windows NT is executing a user change, the PLC continues to operate.

TwinCAT NC PTP and NC I axis control PTP on a PC

The NC server processes the motion control tasks for positioning of switched motors, stepper motors, frequency-controlled (FU) motors and servo-controlled (servo) motors. All widespread kinds of drive amplifiers (servo, FU, stepper motor controllers) and contactors can be integrated via the known interfaces. Position detection is absolute, incremental, by encoder or via the drive. The controller characteristic is defined precisely by way of the acceleration, deceleration and jerk: fine adjustment of the trapezoidal profile of PTP positioning is possible. Commissioning is supported by online menus and measurement tools help to determine the following error, for instance.

Contouring control to DIN66025

Overview 10: Overview 11:

Contouring control tasks are executed in groups of 3 drives in space. They are defined and run in conformity with DIN66025.They are integrated in the PLC in a form that is similar to plain language, i.e. by using function blocks: drive control is integrated in IEC61131-3.Up to 256 axes (depending only on the PC processor used) can be moved simultaneously. Thanks to PC technology, TwinCAT's performance capabilities are constantly increasing.

TwinCAT System Manager links the world with TwinCAT

Overview 12:

The System Manger is the system's configuration centre. The number and programs of the PLC systems, configuration of axis control and the connected I/O channels are related to one another. The System Manager links all system components and their data relations with one another, and data areas and process images are exchanged synchronously or asynchronously. TwinCAT supports all widespread field buses - even simultaneously if necessary. Thus, Beckhoff Lightbus, Profibus DP, Interbus, CANopen, DeviceNet, ControlNet, Modbus, Sercos, RS485/232, Ethernet TCP/IP and USB with a series of master and slave interfaces are currently supported. The PC peripherals (parallel and serial interfaces) and third-party interface cards are becoming available. The System Manager allows a link between server process images and I/O channels in a bit-by-bit fashion and provides tools that consecutively connect 100 channels, for example, with only one command. At the field bus and process image levels of the servers, commissioning and maintenance are facilitated by online display and by "Write and Force". Watch windows show an individual selection of variables. Diagnostic data is offered in a standard representation for all I/O devices.

TwinCAT AdsOCX integrates TwinCAT in Windows NT

Overview 13:

An OCX software or a DLL library provides the link to Windows NT applications (ranging from visualisation through SCADA to Office applications such as Excel). The data transfer methods are defined by the operating systems market leader (e.g. DCOM+, ActiveX, OCX, OLE), with the result that the integration of TwinCAT in Windows NT is based on a very wide-ranging standard. Data transport and method exchange are organised by means of AdsOCX: Windows users can access data and functions of the automation software directly, i.e. without any further driver implementation.