The world is now moving on to integrated safety which integrates safe and standard data on a common network. Even in a decentralized architecture, communication is possible over a single bus, thus harvesting the benefits of integrated safety. In plants users have machines from different vendors communicating on different fieldbuses. These fieldbuses need different safety protocols. These safety standards are proprietary and not compatible with one another. openSAFETY is the only open source and fieldbus independent safety protocol.

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safety & security APPLICATION
Impact of integrated safety
The world is now moving on to integrated safety which integrates safe and standard data on a common network. Even in a decentralised architecture, communication is possible over a single bus, thus harvesting the benefits of integrated safety. ■ Ninad Deshpande
Sep/Oct 2011 | EMover the present system can be highlighted in a number of ways; a few have been described below.
Reduced wiring
■ The present systems have inputs and safety devices. Safety devices have to communicate data to the PLC, this requires wiring. In case of failure of the standard inputs and outputs safety will be adversely affected.
■ Integrated safety will give the benefit of transferring safe and standard data over the same communication network. This avoids unnecessary wiring.
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Present safety systems consist of discrete components like PLC, inputs and outputs, safety relays, safety devices. All these components have to be connected to each other through wires. The safety devices have to transfer safe data to the PLC. The PLC in turn needs to control safe actuators and outputs. Both require intense wiring. Advanced applications also contain motion and in case of motion, speed monitors form a very important feature. Last but not the least, shutting down the entire system should be in a synchronised method. Thus, these can be treated as primitive methods of implementing safety in any machine.
The differentiation of integrated safety
Ninad Deshpande
Application Engineer
B&R Automation
Ninad.Deshpande@br-automation.com

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| 78 | s a f e t y & s e c u r i t y A P P L I C A T I O N
Decreased response time
■ When using the safety relays some delays are induced in the network which can be up to tens of milliseconds. Safety relays will induce some latency in the network.
■ With integrated safety the response time is reduced to less than ten milliseconds. With reduction in the response time danger levels are
also reduced.
Elimination of setup errors
The most important factor in using safety instruments is to parameterise the equipment. In case of wrong parameterisation the system will not be safe. This is very well portrayed in an example in any system plant present in any corner of the world. In the scenario of the failure of a safety device, it needs to be replaced, rewired, and reconfigured. If rewiring and reconfiguration is done with errors, the system will run, but problems will only come to the surface on occurrence of an accident. In another scenario if the system configuration was erroneous at the beginning and this device is replaced, rewired, reconfigured exactly as present in the system thus leading to a replication of error, then this error will be observed in the occurrence of an accident. These sort of human errors are inevitable in case of such
safety systems.
Integrated safety contains the possibility of automatic parameterisation. This parameterisation is through EDS files thus maintaining consistency of
the configuration.
Intelligent safety features
We need large number of safety devices in order to implement complex features. Large number of safety devices lead to extensive wiring and configurations. Handling this can be a nightmare to all. Even after implementing these systems and complex features the problem occurs when we stop the machine. Resuming the process after an emergency stop needs re-initialising of the entire system and synchronisation. This can take an awfully long time and result in a major downtime and production loss. With these systems there are only two options - machine operating with maximum efficiency or stopped due to reasons like emergency, safety breached etc.
Integrated safety offers features like SOS (safe operating stop), SLS (safety limit speed). With SOS one gets benefits of machine stopping synchronously on safety breached or emergency and the process can be resumed with a single push of a button immediately. Thus, due to synchronisation being maintained on stopping, the downtime is reduced extensively. There are certain maintenance activities or safety breaches where the machine need not be stopped completely, this is achieved by SLS. The machine speed is reduced to a safe operating speed.
openSAFETY
openSAFETY is independent of the bus system and interoperable with all transport protocols thanks to the black channel principle. This means that any transport protocol can be used to transfer the safety-oriented data which is packed in a special frame format. When implementing openSAFETY in products one does not need to sign contracts or license for using it. With openSAFETY it is possible to utilize the maximum advantages and features of integrated safety. If component manufacturers develop devices complying with openSAFETY standards the major advantage is the one time development cost incurred. They have to invest only once and the device will function with all fieldbuses. The development and the testing time are also reduced as the openSAFETY standard stack is readily available and the best part is that it is certified and people are legally permitted to use these stacks. The certifications are easy with the TUV certified conformance tests already completed and the interoperability between fieldbuses is
also guaranteed.
The usage of openSAFETY is also of key importance to end users. Any plant might have machines from different manufacturers working on different fieldbuses. The example of a plant shows four machines which can be seen on working over Modbus, Powerlink, Sercos. With openSAFETY different machines will be able to exchange safe data over the same network without problems. Cost reduction, less downtime, higher productivity and easy maintenance are the benefits of openSAFETY.
A case in point
Nestle which is a major player in the food and beverage market has understood the importance of openSAFETY and has requested machine and component manufacturers to implement openSAFETY as a standard for safety in all the plants worldwide. Currently, a Nestlé engineering team in Switzerland is preparing the pilot implementation of a packaging line in cooperation with these automation suppliers in order to develop manufacturer- independent standards for the integration of different control systems. The team is focusing on the use of open communication technologies. “Nestlé uses automation and safety components from various manufacturers. An integrated standard for safety communication allows for a reliable transfer of safety data within the complete plant, irrespective of the manufacturer of its components. Additionally, the standard also facilitates engineering with regard to system design, commissioning, and maintenance and diagnosis of the safety systems.”
openSAFETY is also supported by users like ALSTOM, SIDEL. Thus, the usage of openSAFETY is not limited to any one industry. openSAFETY is even being considered as the next generation standard for safety in air and space
industry in Europe. ■
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The usage of openSAFETY is also of key importance to end-users