Client Goal

Faced with increased demand for its products, a large Portland cement manufacturer had to expand and modernize its Pack-House production operation. To successfully fulfill the project’s primary goal of improving customer satisfaction, our client had to sack and palletize its product with more consistency and uniformity as well as load the trucks faster. The project required the replacement of the inflexible, outdated relay logic based control system from 1960’s and the automation of labor-intensive tasks. The new control system had to offer an automated solution to configure product flow from storage silos to the processing equipment and offer an intuitive means for fault handling as well as a seamless interface to a new Bagging and Palletizing system.

Project Overview

Tegron Solution

The control system solution for the Pack House Controls Modernization project was based on an Allen-Bradley ControlLogix PLC, Allen-Bradley industrial control hardware, and Rockwell software products. The MCC was built from a basic Allen-Bradley IntelliCENTER® Motor Control Center. Each bucket was custom wired to our customer’s standards. The MCC was fitted with two extra sections. The first contained all PLC hardware and communication modules and the second was a pre-wired marshalling cabinet. With the new design all field devices are wired to a single location, simplifying system maintenance and troubleshooting.

ControlNet was utilized as the means of communications between the PLC and the remote I/O located within the new MCC. ControlNet was also used as the interface to the new PanelView Plus 1500 human machine interfaces. One PanelView 1500 was located in the Pack-House and the other in the plant’s Central Control Room. DeviceNet was used as the in-MCC communication network. Each motor control bucket contained an Allen-Bradley E3 Plus electronic overload relay for monitoring of each motor and to provide I/O within each MCC bucket. The signals were utilized throughout the PLC program for controlled shutdown and for motor status displayed on the PanelView for maintenance purposes.

Customer Benefits

The overall performance of the new control system has increased the uptime of the facility. The plant has increased production from a 700 bags per hour average to a 1000 bags per hour average. With the new packaging system the plant experiences less wasted product, cleaner bags, more consistent bag weights and evenly stacked pallets. The time to load each truck decreased, satisfying their customers request for faster service.

The new recycle system allows the plant to sack all products and recycle at the same time, a feature the old system did not support. Also the recycle system has increased from about 80 tph (tons per hour) to 100 tph with one compressor and at present about 140 tph with both compressors.

Supporting Services

The project included a comprehensive electrical documentation package, documented PLC and HMI configuration files, and a detailed functional specification on CD to ensure proper maintenance and service of the system. The project also included comprehensive training for system operators and maintenance personnel.

Scope of Supply

Services Delivered:

• Project management.
• Electrical design including architecture and detail
• Electrical documentation
• UL 508 MCC fabrication
• Integrated testing of motor control center base control system
• Functional specification development
• PLC and HMI software programming.
• Startup and commissioning of power, controls, and I/O
  wiring.
• System training

The Outcome

Production Benefits:

• Increased our customer’s customer satisfaction
• Decreased over-all “Truck Load” time
• Increased quality of sacked products
• Added consistent uniformity to pallet stacks
• Increased bagging capacity from 700 per hour to 1000 per hour
• Increased product recycle from 80 tph (tons per hour)
  to 100 tph with one compressor, 140 tph with both compressors.