How Trutegra’s intelligent bridge crane controls, with SCALANCE wireless broadband technology, save an automotive supplier hundreds of thousands of dollars.
Automakers are buying huge volumes of high-strength steel as they attempt to build solid, lightweight cars. Annealing and galvanizing plants throughout the Midwest process these thin steel sheets, creating steel coils that weigh up to 40 tons.
Hoisting and moving these huge coils through the plant is no simple task, it requires large bridge cranes that are precisely controlled. When multi-ton loads are being moved, slips, bumps and drops can’t be tolerated. Accidents can have grave impact on nearby personnel, equipment and infrastructure.
One Midwestern annealing and galvanizing company uses four giant bridge cranes to hoist and transfer these massive coils through its plant. The bridge for each crane spans 120 feet, while it runs overhead on two rails 2,000-feet long.
The facility’s bridge has a trolley with a powerful hoist system to lift loads. The hoist is connected to a rotating mast, so loads can be turned. This system lets crane operators move massive loads quickly around a facility. However, the basic system doesn’t have technology that prevents accidents.
To prevent collisions and other catastrophes, the steel processor turned to Trutegra, a Charlotte, N.C.-based developer and integrator of comprehensive control and automation solutions.
“Trutegra is globally known for its sophisticated crane control solutions, especially those offering intelligent positioning of cranes and hoists,” says Mike Martin, Trutegra’s Information Technology Manager. “With industrial cranes, control is everything. Our customers count on us to help them ensure their cranes operate efficiently and safely.”
Modern bridge cranes are usually fully automatic, but older models can be manual or semi-automatic. Manual cranes can be operated from an onboard operator cabin or remotely from a control room via video cameras.
Real-time communications between the operator and the crane’s components is vital to their efficient, safe operation. For years the plant’s bridge cranes had used a 900 MHz leaky coax cable communications that ran along the rails.
“Although their cranes could operate automatically, they could also guide loads manually, if necessary,” says Martin. “In that case, a worker would walk onto the production floor to use a belted set of wireless controls called a ‘belly box.’ That puts the operator in harm’s way.”
The company decided to overcome that hazard by upgrading the facility with 802.11n wireless broadband. One reason was for the upgrade was a plan to put cameras on the cranes so operations could be monitored from a remote control room.
Another reason was that they could collect operational data and store it on a DVR so they could analyze the actions that preceded mishaps. Unfortunately, they chose a vendor with a wireless solution that they couldn’t get to work, even after a year of trying.
“The crane’s vehicles would lose communication long enough that it would stop production eight to twelve times per shift,” Martin says. “When these outages occurred, they’d have to send someone out there with a belly box remote control, and manually drive the crane to a maintenance location. They’d then shut the power off the crane and reboot it, so the radio would reboot and come back on. The disruptions probably cost the plant hundreds of thousands of dollars in lost productivity.”
When Trutegra got the call, its engineers visited the plant and quickly determined that it needed a proven broadband wireless control system that worked flawlessly. The Trutegra team recommended an industrial wireless LAN comprised of Siemens SCALANCE W788 Access Points and W748 Client Modules. It offers a combination of capability, reliability and security in a solid-state, ruggedized aluminum package.
Using MIMO (multiple-input, multiple-output) technology to multiply the capacity of their radio channels, they achieved bandwidth throughputs of up to 450 Mbit/s, more than enough for the customer’s requirements. The access points and client modules can be rail or wall mounted, with Power-over-Ethernet (PoE) to minimize cabling. Protection against unauthorized access is provided by data encryption and standard user authentication mechanisms.
Reliability was obviously a critical factor for the steel processor. Trutegra designed a redundant system for one of the plant’s cranes, placing one SCALANCE W788 Access Point high on the wall at each end of the plant’s building.
Connected via Ethernet cabling and powered via PoE, they communicate back to plant’s SCADA system as well as bring the video signals to the control room and DVR, all via Profinet. The crane’s vehicle control box was outfitted with a SCALANCE W748 Client Module. Trutegra set the units to their highest security encryption using technology Siemens builds into the modules.
Martin notes that Siemens sent its top wireless network expert in the region to ensure a smooth installation and configuration for the SCALANCE W wireless LAN.
“That’s typical of the kind of support we get from Siemens,” Martin reports. “Our installation took about eight hours to mount the units, hook them up to the network, and tune everything.”
According to Martin, his customer is delighted. They haven’t had a single outage since the installation.
“That alone has saved them the hundreds of thousands of dollars in productivity they were losing with their previous wireless system,” Martin says. “And they don’t have the safety issue of putting a person out on the floor 12 times a shift to manually drive the crane to its maintenance position and reboot it.”
Trutegra’s customer recently decided to upgrade its three other cranes at the first facility and five more in another location. Now that they know how easy the installations are, plant maintenance people handle installations.
“We documented the installation steps for them and their own staff took care of installing the units, connecting them to the network and setting them up,” says Martin. “They were so confident that the Siemens SCALANCE W system would run out of the box, they didn’t ask us to be on site but would call if they needed us. And they didn’t call.”
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