When safety communications use the same cabling used to link equipment, installations and diagnostics are simpler and less costly
Safety has become one of the watchwords in industrial environments over the past few years. However, enhancing safety is often perceived to counter two other common goals: reducing costs and simplifying installations.
The transition to Ethernet connectivity is helping developers meet these conflicting objectives. Industrialized versions of the ubiquitous network let system integrators use the same network for operations and safety. While this trend began with wired connections, it’s rapidly expanding to include wireless links. The hardwired safety networks of the past are rapidly disappearing.
Those who are reaping the benefits of eliminating hard-wired safety range from main stream industrial users to the Statute of Liberty and Disney’s California Adventure. Using a single network for data and safety brings a number of advantages.
Hardwired connections weren’t an option on Disney’s Cars Land, a 12-acre ride based on the popular animated movie. In a Disney amusement park, reliability and safety are paramount. Cars Land has become one of the most popular rides, so an unplanned shutdown or an injury caused by a technical issue isn’t an option.
Disney’s imagineers employed a wireless PROFINET architecture to pull safety and operational data from vehicles and remote stations. That data is fed into an Ethernet backbone that routes data to managers throughout the California Adventure site.
“PROFISAFE, a safety protocol that runs over PROFIBUS and PROFINET, can be just as reliable on wireless connections as with tethered networks that use cables,” says Greg Richards, Safety System Engineer at Siemens. “PROFISAFE wireless has been certified by TUV to meet the requirements of SIL 3, which is the highest safety integrity level under IEC62061 for Industrial Machine Safety.”
Wireless links have been approved by safety agencies. For example, the National Fire Protection Agency included wireless safety networks in NFPA 79 2012, Richards added. One of the keys for wireless safety networks is to run a site survey to determine signal strength and time delays. That ensures that all areas are covered and signals will arrive in a timely manner.
The growing focus on wireless doesn’t diminish the importance of tethered connections, which remain the mainstream for safety. The engineers who updated a rescue elevator in the Statue of Liberty saved plenty of space by using PROFINET. The elevator was installed in the early 1980s to remove visitors who had trouble scaling the spiral staircase. When it was redesigned, product planners eliminated a hardwired safety network, replacing the bulky wiring with conventional networking cables.
“When you have a single Ethernet cable for all your I/O, it’s a lot easier to install than running a big bundle of cables for the safety connections,” Richards says. “It’s also easier to troubleshoot, since PROFINET has extensive diagnostics.”
Those benefits are also attractive for companies using more conventional industrial applications like automotive, aerospace and food processing. Using a single network for safety and operational connections makes it much easier to reconfigure facilities to meet the rapid changes that can occur in modern manufacturing facilities.
Networks also help companies improve safety when they upgrade their facilities to speed up production. An automotive manufacturer wanted to add safety to its widely-used PLCs, while also improving diagnostics. They installed Siemens ET 200S fail-safe motor starters, connecting them to other systems via PROFINET. That saved space and time, while also providing excellent diagnostics, while still meeting the original goal of improving performance. Reduced downtime was an added benefit.
The benefits gained in that work cell can be multiplied in large facilities. It’s not just the cost and complexity of connecting multiple wires. Some pieces of equipment may not be able to support the necessary wiring.
“If you’ve got 10 drives in your system, you’re looking at a lot of wiring, if you are hardwiring the safety functions. Another factor is that some of the hardware may not have connections capabilities for all that wiring, thus limiting the safety functions you can use” Richards says.
Simplifying the networking architecture can also make it simpler to keep abreast of current software and technology advances, while also simplifying the task of updating security technology. Security has become an important factor over the past few years as Ethernet connections gave hackers and others more access to industrial networks.
Constant vigilance is needed to thwart those who create malware or attempt to extort plant managers by taking control of some equipment. Security technology must adapt to the latest malware techniques, making common networking technology a critical element.
An aerospace manufacturer wanted to employ off the shelf automation equipment that could be easily upgraded while providing life cycle security. They integrated an ET 200F CPU & SINAMICS 120 gear using PROFINET, bringing three separate functionalities together. After seeing the equipment architecture in operation over time, the manufacturer was pleased with the improvements, in improving response times and providing life cycle security along with the ability to upgrade equipment as new products were acquired.
These concepts have been used in a broad range of industrial environments, from chemical and pharmaceutical manufacturing to construction equipment to semiconductor production. In these fields and others, users have gained a number of benefits when they upgraded to improve safety. In some instances, these additional advantages overshadow the improvements in safety, in part because the lack of safety failures moves injuries into the background.Have an Inquiry for Siemens about this article? Click Here >>