TECHNOLOGY: Two-A-Day Keeps It Fresh
Recent Western Cape Business News
THE Grabouw-based Two-a-Day Group, one of the leading fruit growing, packing and marketing companies on the African continent has met the challenge of controlling and monitoring its cold storage and packaging plants with the assistance of solutions from specialist in energy management, Schneider Electric.
Located in the Elgin Valley near Grabouw in the Western Cape, Two-a-Day needed to install a monitoring and control system that would be able to record the sequence of events for faults as well as ensure correct operating conditions within its pack sheds, which run 24 hours for the months between February and November, in order to meet the growing demand to supply fresh apples and pears.
Says Andries Le Roux, regional sales manager at Schneider Electric: “A vital factor in the great success of Two-a-Day has been its controlled atmospheric long term storage technology, which allows a reliable, year round supply of quality fruit that is quite literally as fresh as the day it was picked.”
The organisation’s cold storage facilities regulate the oxygen content by taking it to extremely low levels to prevent the fruit from ripening. “Only the best apples and pears are put into Controlled Atmosphere (CA) storage and kept there for up to ten months,” explains Hennie Barnard, senior electrical technician at Two-a-Day. “We have enough capacity to keep up to 80 percent of our crop in CA storage. The fruit not going into CA storage, which is also normally the first fruit that is packed during harvest time, is cooled down in regular cold storage where oxygen levels are not regulated. When the fruit reached a set temperature, it goes to the pack sheds where it is packed. In addition, Two-a-Day has carton re-cooling stores, where all cartons that have been packed are re-cooled after packing to a prescribed setpoint. The fruit is then moved to the warehouses, where it is kept under strict control conditions, before being shipped to clients.”
In order to automate these sensitive systems, Two-a-Day opted to install a wide range of Schneider Electric products from PLCs, soft starters for pumps and fans, medium and low voltage equipment, HMI (Human Machine Interfaces) equipment and Variable Speed Drives (VSD) as well as networking and switching solutions for 113 CA storage warehouses, 13 Regular Atmosphere (RA) rooms, four pack sheds and compressor rooms.
“An installation of this type – maintaining the right temperature and regulating the gas, O2 and CO2 contents to extreme low levels – can only be handled successfully with an optimised control strategy,” states Le Roux.
“The main objectives of this project were to enable Two-a-Day to connect a wide variety of different sensors and actuators, time tag events, easy configuration and commissioning, debugging and simulation support and, most importantly, the emergency stock and availability of all products.”
After a detailed evaluation phase, Schneider Electric’s Modicon Premium programmable controllers were chosen for the automation of the project.
Almost 50 Premium PLCs automate the packaging and cooling plants and have been programmed with PL7 and Unity Pro programming software.
The programming of the PLCs was completed quickly and efficiently via an Ethernet network, in both standard wire and fibre optic.
Modicon TSX Premium PLCs support the system structuring approach by having Ethernet integrated into the CPUs. Each packing department’s PLCs are located in control cabinets and communicate with each other via Ethernet.
“Due to the open and flexible architecture of the Premium PLC series, the automation system could be adapted completely to the requirements of the plant,” explains Le Roux.
Each control room within the pack sheds has its own HMI (Human Machine Interfaces) system, using the 4, 5, and 7 inch screen sizes of the Magelis range. The connection of the PLCs to the HMI systems was done via Ethernet.
Each cooling facility also has its own HMI, which connects the information to the central control supervisory centre in the administration building, from where the refrigeration foreman and standby personnel can also control and monitor via a dialup connection.
A combination of Schneider Electric’s M340 Ultra-Compact PLCs, a hard-working controller designed especially for small control systems, Premium PLCs, Ethernet technology and PT100/PT1000 platinum resistors for temperature measurement were used within the CA storage warehouses.
“The Two-a-Day Group is proof that upgrading automation technology and keeping up to date is critical,” states Le Roux. With the constant update in technology, the supply chain can be enhanced without huge costs.”
“Automation downtime has been reduced from eight percent to two percent by automating all the packaging plants (monitoring start up sequences in packaging houses),” adds Barnard. “Each operating house functions independently although all of the PLC data can be controlled from one central point which makes control so much easier.”
The system integration, including the configuration and commissioning of the automation, was done by the engineering division of Two-a-Day.
Technoserve, an authorised partner of Schneider Electric, supplied all of the Motor Control Centre (MCC) panels using Schneider Electric’s Prisma panel systems.
Two a Day is currently undergoing an expansion exercise and is in the process of building 16 new CA storage rooms.
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