The Allen-Bradley ControlLogix and GuardLogix programmable automation controllers (PAC) offered the necessary performance with an easy-to-use development environment. The high degree of integration of the PAC, I/O modules and the programming software also reduces the time required for development and commissioning.
Standard PACs and safety PACs are installed in a common rack in order that the safety functions can be implemented easily alongside the control program, addressing the functional safety requirements in conformity with the Machinery directive. Integrated motion modules simplify the control of the servo axes and their incorporation into the process program.
To control the process plant, various measurement and control tasks must also be undertaken using an array of instruments and features, all of which are connected to the PAC using a variety of communication interfaces.
The control of pumps, valves and analogue measurements is realised using remote Flex I/O nodes that are accessed via ControlNet. The pressure measuring equipment is accessed via DeviceNet as are the gas controllers. The control unit that controls the electron beam, which is a powerful real-time system, is also operated via DeviceNet. Commands and set points can be sent directly from the PAC, making it possible to react very quickly to feedback from these control units.
From a safety perspective, the CompactBlock Guard Safety I/O is connected to the GuardLogix PAC over DeviceNet using CIP Safety. The requirements relating to the safety of machine control systems in accordance with DIN EN ISO 13849-1 can be realised efficiently and with significant cost advantages by means of integrated safety. This usage of common components for standard control systems and safety control systems also minimises costs for hardware, software, development and support.
The motion solution comprises an Allen-Bradley Kinetix 6000 multi-axis controller, which is integrated into the control system using Sercos. The complex multiple-axis motion control for the manipulation of the turbine blades was implemented in the RSLogix 5000 development environment and therefore did not require any interfaces to external systems.
Thanks to the integrated safety option for torque shutdown (Safe Torque-Off) the Kinetix servo drives meet the safety standards up to SIL3/PLd. The stop categories can be realised within the safety routine.
The system is operated using an HMI PC and an Allen-Bradley PanelView Plus. The PC is used for recipe preparation, operating mode selection, process information display and logging, while the PanelView Plus attached to the loading chamber is used to operate the manipulator's servo axes.