CEMEX benefits from Integrated Architecture approach from Rockwell Automation.
Background
CEMEX, a global building materials company, provides high-quality products and reliable service to customers and communities throughout the world.
Its operations network produces, distributes and markets cement, ready-mix concrete, aggregates and related building materials in more than 50 countries, and maintains trade relationships with more than 100 nations.
Challenge
With its use of Climafuel expanding – from 30 to 60% – CEMEX’s Rugby plant, the largest cement works in the UK, needed additional unloading and conveyor capacity to complement the pair of bays already in existence.
The loading bays use a combination of screw conveyors and walking floors to transport the Climafuel from the lorry unloading area to the kiln.
As well as the automation demands, the new loading bay also needed a safety infrastructure to help protect employees and fuel delivery drivers.
The company originally specified an Allen-Bradley ControlLogix programmable automation controller (PAC)-driven solution from Rockwell Automation, but with automation and safety components supplied by different third parties.
Solution
Westbury Control’s solution was still based on the ControlLogix PAC, but all the other primary components were also from Allen-Bradley – running on an EtherNet/IP network. In addition to the PAC, the automation and safety solution comprised of PowerFlex 755 drives for driving the motors, E1Plus solid-state overload relays, Stratix switches, SmartGuard 600 Programmable Safety Controller, GuardShield safety light curtain, SensaGuard RFID Coded non-contact safety switches and actuators, RightSight™ photoelectric sensors and 440T ProSafe coded key exchange switches.
According to Daron Shaw, electrical plant development engineer at CEMEX’s Rugby plant: “The unloading pod, which resembles a large cube with one open face, could have potentially been a dangerous place to be because of the exposed screw conveyors, hence our requirement for the safety solution. What is more it had to be automatic and not reliant on the actions of the drivers.”
Paul Knott, from Westbury Controls, explains the principal: “In operation, lorries are reversed into the bay and the drivers enter via side doors to undo the clasps on the back of the trailer.
The safety solution, driven by the SmartGuard 600, uses a safety light curtain to detect personnel and photoelectric sensor array across the open face of the cube to detect the presence of a lorry.
If either the safety light curtain is operated or the side doors are opened (protected by the 440T Prosafe coded switches and monitored by the SensaGuard switches), the system shuts down by interrupting the power to the motors.
The safety logic dictates that the system only re-activates when a lorry is present, both side doors are shut and a restart button is pressed by the driver. The unloading pod side doors are also fitted with a trapped-key interlocking system to make sure that the driver cannot become locked inside the pod while undoing the trailer clasps.”
Westbury Controls has also written all the software for the installation.
Results
“After a visit to Rockwell Automation’s UK headquarters in Milton Keynes for a demonstration of the technology we became convinced that this was the way to go,” Shaw elaborates. “The E1Plus is a revelation, as it will allow us to easily justify the investment of intelligent components on a cost basis.”
The beauty of this system,” Knott explains, “is that CEMEX has been able to achieve more intelligence and greater functionality at no additional cost compared to the initial specification.
“The intelligence now available to CEMEX will allow them to target specific timeslots for downtime,” Knott elaborates. “As motor performance details can now be collated, historic data will allow them to identify trends and formulate maintenance plans accordingly.”
