Beckhoff: TwinCAT 2 (TX1260 Series)

The Windows Control and Automation Technology

The Beckhoff TwinCAT software system turns almost any compatible PC into a real-time controller with a multi-PLC system, NC axis control, programming environment and operating station. TwinCAT replaces conventional PLC and NC/CNC controllers as well as operating devices with:

TwinCAT architecture

TwinCAT consists of run-time systems that execute control programs in real-time and the development environments for programming, diagnostics and configuration. Any Windows programs, for instance visualization programs or Office programs, can access TwinCAT data via Microsoft interfaces, or can execute commands.

A practically oriented software solution

TwinCAT offers a precise time base in which programs are executed with the highest deterministic features, independently of other processor tasks. The real-time load on a PC is set with TwinCAT; defined operating behavior is achieved in this way. TwinCAT indicates the system load for programs that are running. A load threshold can be set in order to assure a defined computing capacity for the operating programs as well as for Windows NT/2000/XP/Vista or Windows 7. If this threshold is exceeded, a system message is generated.

TwinCAT supports system diagnosis

The general use of hardware and software from the open PC world requires some checking: Unsuitable components can upset the PC system. Beckhoff has integrated a practical indicator of the real-time jitter, giving administrators an easy way to evaluate the hardware and software. A system message during operation can draw attention to incorrect states.

Start/stop behavior

Depending on the setting, TwinCAT is started and stopped manually or automatically. Since TwinCAT is integrated into Windows NT/2000/XP/Vista and Windows 7 as a service, an operator is not needed to start the system: switching on is enough.

Restarting and data backup

When a program is started or restarted, TwinCAT loads programs and remanent data. To backup data and to shut down Windows NT/2000/XP/Vista and Windows 7 correctly, a UPS (uninterruptible power supply) is of great value.

TwinCAT and “Blue Screen”

The TwinCAT system can be configured such that real-time capability is maintained in the event of a BSOD (Blue Screen of Death) operating system crash. Real-time tasks such as PLC and NC can therefore continue to run and bring the controlled process into a safe state. Ultimately, it is the decision of the programmer whether or not to utilize this feature, bearing in mind that data or programs may already have been destroyed by the BSOD.

World-wide connection through message routing – “remote” connection is inherent to the system

According to the requirement for operating resources, the TwinCAT software devices can be distributed: TwinCAT PLC programs can run on the PCs or on Beckhoff Bus Terminal Controllers. A “message router” manages and distributes all the messages, both in the system and via TCP/IP connections. PC systems can be connected with each other via TCP/IP; Bus Terminal Controllers are integrated via serial interfaces and fieldbuses (EtherCAT, Lightbus, PROFIBUS DP, CANopen, RS232, RS485, Ethernet TCP/IP).

World-wide access

Since standard TCP/IP services of NT/2000/XP/Vista/CE and Windows 7 can be used, this data can be exchanged across the world. The system offers scalable communication capacity and timeout periods for the supervision of communications. OPC provides a standardized means for accessing many different SCADA/MES/ERP packets.

TX1260 | TwinCAT NC I

Follow the path with the PC

The TwinCAT NC Interpolation (NC I) is the NC system for interpolated path movements. TwinCAT NC I offers 3-D interpolation (interpreter, set point generation, position controller), an integrated PLC with an NC interface and an I/O connection for axes via the fieldbus. All well known Fieldbus systems and programming standards in the CNC world, such as DIN 66025, are supported. TwinCAT NC I delivers open PC solutions for standard axial components and CNC controls. TwinCAT NC I uses the power of the PC and allows axis regulation under Windows NT/2000/XP/Vista/CE or Windows 7. Hardware modules are simulated in the software, and are thus superfluous.

TwinCAT NC I – interpreter

The syntax which is laid down in DIN 66025 is a reliable descriptive language for machine sequences. There is also an additional extension to the DIN syntax with a number of useful functions:

3-D interpolation

The following geometries are supported by the interpreter:

TwinCAT NC I – operating interface

An operating interface integrated into the TwinCAT System Manager provides information on all set and actual values and on the physical and logical state of the interpolation channels and interpolation axes. The NC structure and many NC parameters are also set using the System Manager.

Online changes of configuration of the axes

Individual PTP axes can be collected flexibly, when the axes are stationary, into new interpolation groups, after which they can be reconfigured as PTP axes. In this way all PTP characteristics such as reference run, tool change, etc. can be used.

PLC blocks for interpolation

In order to create a simple interface for axis interpolation, PLC blocks which can create positioning commands for the interpolation channel, using easily understood descriptions organized as tables are available.

TwinCAT NC I – pathway dynamics

A rate-of-change limited profile, which at any moment describes the acceleration, speed and position on the path as well as the associated transformed Cartesian axis values. The maximum allowed dynamic limiting values can be changed at any time in the NC program.

TwinCAT NC I – path override

TwinCAT NC I possesses a speed override function which can synchronously work on all of the axes.

Speed reduction at curves

TwinCAT NC I offers different reduction methods for reducing the speed on neighboring geometrical crossover points. The parameter for this speed reduction can be changed in the NC program.

TwinCAT NC I axes

For each channel three path axes (X, Y, Z) can be used. In addition, five further auxiliary axes can be integrated into the channel. These are interpolated with the path, i.e. they start with the path segment and arrive in the target position with the path segment.

“Look Ahead”

The “Look Ahead” function calculates the maximum possible path velocity at segment transitions. It can take into account all entries in the NC core and connects neighboring geometries so far as this is possible.

Slave coupling on the path axes

A master/slave coupling on a path axis is possible, independently of which slave type is involved.

Geometric-dynamic smoothing

Various options are available in order to achieve optimum geometrical and dynamic smoothing at segment transitions (e.g. Bezier smoothing). In this way, the path velocity can be kept constant at segment transitions if the boundary conditions are suitable. This is particularly important for pick-and-place tasks and manipulations (e.g. laser welding).

Diagnostic and optimization possibilities

All machine state variables can be extracted and displayed for diagnostic and analysis purposes. An ideal tool in this respect is TwinCAT ScopeView, which allows all internal and external variables to be recorded. These variables include path values (set and actual values) such as path speed, path acceleration, tangential and orthogonal path error as well as Cartesian values such as position, speed, following error, etc.