The “Fruits” of Carefully Integrated Automation: Controlled Atmosphere Storage

Automation behind controlled atmosphere storage helps keep apples fresh for up to one year.

Keeping fruit fresh until it arrives at the grocery store is no easy feat: Temperature, oxygen and nitrogen levels, carbon dioxide levels and humidity all must be controlled. When these controls function properly, produce can be kept fresh in “controlled atmosphere” storage for many months from harvest until stores are ready to stock. For example, certain varieties of apples can stay fresh for 12 months and some pears can stay fresh for 10 months.

Designing a “controlled atmosphere” storage facility requires careful coordination and integration of many systems to maintain the delicate balance needed to keep produce fresh.

Consider the plans that go into designing new controlled atmosphere (CA) rooms for Central California, the nation's top producer of fruits and vegetables. The food producer seeks expertise from California Controlled Atmosphere (CalCA) to keep CA rooms within specifications, as the company is known for engineering expertise and has much application-specific knowledge when serving the industry, which is heavily regulated for food safety.

In the past CalCA would use programmable logic controllers for CA room and facility controls, only to find the software was made obsolete or became unsupported after five years. To achieve longer operational life––around 20 years––it needed a new option, one that could also offer flexibility for changes on the fly and ability to be deployed at small control environments and scaled up when required.

After researching the market, CalCA chose Opto 22’s SNAP PAC control and I/O system for automating and controlling CA facilities and rooms. The SNAP PAC System consists of programmable automation controllers (PACs), I/O modules and racks, and “brains” (I/O and communication processors) that interface physical I/O signals with Ethernet networks. To develop control programs and an HMI, the SNAP PAC System comes with the PAC Project Software Suite, which includes PAC Control for control program development and PAC Display for building a PC-based HMI.

Learn more about the automation behind CalCA’s support for controlled atmosphere rooms.

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