Client: George Weston Foods
Project: Flour Mixer Controller Replacement
- PLC programming
- HMI design and programming
- MCB design and build
- Operation manual written
- Wiring and circuit diagrams
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Background
George Weston Foods (GWF) are a multinational company manufacturing and supplying a wide range of food products to New Zealand and Australia. At their factory in Wiri, they had a very old Electrical Controls Systems (ECS) weigh station that formed an integral part of their mixing plant. This mixing plant makes the dough for their high quality bread rolls. GWF’s National Projects Manager, Bruce Wheeler, identified this as a critical piece of equipment that needed to be upgraded. The existing controller was a propriety, printed circuit board based, controller that was no longer supported. The company that originally supplied the mixing station was no longer in business. There are no spare parts therefore if this controller failed it would affect the company’s ability to produce their saught after rolls. Bruce had a number of large projects on the go at the same time and needed someone to take over this entire project.
Problem
No one was sure what the existing ECS controller did. The controller was not one of GWF’s preferred equipment suppliers. The existing unit communicated to two separate controllers that dosed flour and yeast to the mixing plant. GWF needed someone to learn what the controller did, design and build a suitable replacement that matched their current factory requirements, install and commission the plant and supply operational manuals and full electrical drawings. All this had to be done within the Capex that was granted for this project a year ago that assumed it would all be completed in house. The mixing plant is used 24hrs a day 7 days a week except for one 8hr period per week. So whatever replacement that was to be installed, had to be installed and commissioned within this tight time frame.
Solution
N2P Controls met Bruce and was able to offer a fully package solution that not only replaced his existing controller but the entire MCC cabinet associated with this controller. Due to N2P Controls bulk purchasing power, and thanks to N2P Control’s supportive suppliers, N2P Controls was able to offer this fully package solution within Bruce’s original Capex budget.
N2P Controls senior engineer, Peter Taylor, spent several hours with the operator at the existing plant understanding its operation. He then studied the communication between the existing controller, the yeast controller and the flour controller. Based on his findings he designed a replacement. 
N2P Controls built an entirely new gear plate, upgrading the old equipment with new equipment, while taking care to ensure the operation and feel for the operators would be very similar. The advantage of a complete new gear plate was that it allowed a complete swap with the existing gear plate. This significantly reduced the required installation time on site. N2P Controls also took this opportunity to add some operator friendly interlocks to the program that would eliminate accidental product drops.
The Technical Stuff
GWF utilises Allen Bradley PLCs. For the size of this project a Micrologix 1100 CPU was deemed suitable with an analogue input, analogue output and digital output module added. A Ethernet hub was used for communicating between the modules. A PanelView 7000 was chosen as the operator’s interface.
The program had 26 inputs and outputs. These were a mixture of digital and analogue. The interface with the yeast and flour controllers were with discrete inputs/outputs. The program was designed with the ability to easily upgrade for different recipes in the future.
Outcome
During one 8 hr production break, N2P Controls successfully replaced the gear plate, commissioned the new controls and trained the staff. The new controller has run problem free since with operators commenting that there has been increased efficiencies already with no accidental product drops.
At a time when GWF had a large scale project being implemented, N2P Control’s package solution and commitment to the project, allowed them to complete the project in the tight time frame required. Bruce commented that he has been impressed by the ”professionalism” shown by N2P Controls and is very happy with the “great job” completed by N2P Controls. Just as important is that the Operators are also happy with the new system.
If you have a project that needs anything from PLC programming through to a total package solution, call N2P Controls and let them help make your next project a success.
