There has always been some form of Safety systems implemented in industrial manufacturing automation. The manually driven, hardwired safety systems of the past are losing their place in the modernized plant. In the last five to six years, you would not even see these integrated systems. Today, the trend is moving toward making safety more methodical and even more safe by integration into the core of the control systems – not just added as an afterthought. We find that integrating safety systems into the line control systems at the plant floor is now a part of the safety system design and a requirement in the electrical specs of most of our clients. We certainly encourage all customers to follow this methodology.
In old style architecture, you would see hardwired safety systems that were certainly functional, but they lacked key areas to protect against possible failure creating an unsafe situation. There is now redundancy in the devices, the mechanics, the electronics and the software/hardware. Now, we can centrally manage all of the safety devices such as pushbutton E-stops, pull cords and light curtains that are integrated directly into the line control system and programmed for flexibility to easily control these devices in zones while maintaining safety ratings.
The safety system converges with the line control systems and is held separate and managed based on safety level requirements. This allows the safety system to be validated separately and provide plant wide consistency. Key benefits of an integrated system are:
Some Operators tend to use the E-stop as a convenient method to stop the machine. E-stops are designed for emergencies, but are used in non-emergency scenarios all too often to stop the line. This generally causes longer downtime and impacts production related to restarting of the machines. An integrated Safety System provides the ability to create safety zones to control how the line is stopped or areas of machines are safe for access to clear jams without stopping the machines or the entire line. Now criteria can be developed and programmed into the integrated safety software to provide safe access and maintain productivity on the line. Before, those changes had to be made with hardwiring and machine changes.
Disparate controls and data slow down operations. By integrating all of the safety controls, plant managers and operators can easily view the data, identify the problems and decide the best course of action. Diagnostics and alarms can be designed from collected safety information. The customer would determine how they want to monitor the system and what data they want to see, such as downtime monitoring. Before it was nice to have data; now it is required to have data. Supervisory software can drill down to interrogate each device to allow the engineering staff the data to access the device to monitor the equipment for failures, frequent incidents in order to make adjustment for OEE improvements. The fault-codes provided will tell engineering exactly what happened. Our objective is to provide a data-rich environment.
Flexibility on a line has become increasingly important for manufacturers to meet changing customer demands. Where hardwired safety systems were analogous to casting concrete or carving stone, digitally integrated safety systems are designed to be nimble. Standardized design allows for changes on the line and expansion efficiencies. The installations typically only require a couple wires and new parts and old parts can be swapped out in minutes.
OSHA requires, in general, that the employer is to provide a safe work environment and that there is a proven method used to assure that one exists. Therefore OSHA relies on ISO-13489-1 to define what makes an integrated safety system safe. The ISO-13849-1 standards helps define the safety (Performance) level, the safety functions required, the safety control system to be used, and the safety devices to be used. This is all done by identifying the hazards defined in a Risk Assessment. By understanding these requirements, designing and integrating the system to these standards, and properly documenting the safety system customers can be assured that OSHA requirements are met and that a safe system has been integrated.
If you would like to see what an integrated safety system can do for your operations, please reach out to us today.