The Challenge:
Replacing ineffective automation to promote recipe consistency and boost production for large-scale ice cream production.

The Solution:
Using National Instruments Lookout to create an inexpensive and easy-to-use PC-based human-machine interface (HMI) to control the ice cream batching system.

"In the past, much of the recipe was mixed manually, leading to a possibility of human error that Lookout has virtually eliminated by removing mechanical switches and counters from the system."

Since 1907, Blue Bell Creameries has been producing and distributing premium ice cream. This Texas company is fastidious in protecting its homemade secrets and in maintaining the quality and consistency that has made their products favorite desserts over the years. Today, Blue Bell products are available in 12 states, along with Mexico, Greece, Guatemala, and in several Middle Eastern countries. To accommodate the growing demand for its products, the company combined homemade recipes with National Instruments Lookout to control their batching system.

The Process

The recipe management Lookout provides is essential to making Blue Bell ice cream. In the past, much of the recipe was mixed manually, leading to a possibility of human error that Lookout has virtually eliminated by removing mechanical switches and counters from the system. Because Lookout automates the batching system, Blue Bell can concentrate their efforts on maintaining product quality.

With the field-proven object-based architecture of Lookout and its ease of use, Lookout helps control the process of mixing flavors and ingredients in various labeled tanks. In these tanks we can adjust the exact percentage of fat, butter fat, milk, and other ingredients we are using to create different products. Once Lookout appropriates the correct ingredients from the control room interface to the mixing tanks on the floor, the initial mixture is blended. Using the automated production system and Lookout, Blue Bell produces three mixes at one time and can make 10 to 12 different flavors (out of 30) year-round.

System Configuration

At Blue Bell, we use a Pentium computer running Windows NT that connects to a TCP/IP Ethernet hub. The Lookout PC communicates over TCP/IP to Siemens TI545 controllers to call up recipes for different ice cream flavors. The application currently has 171 preset I/O, 2 screens, and two programmable logic controllers (PLCs). Lookout has a driver for the Ethernet card and interfaces with Visual Basic to couple with PLCs from TI which control valves, pumps, and mixers. Lookout connects between the Visual Basic package and PLCs for three blend room units, which draw and mix ingredients. Unit one has a single blending operation with one pasteurizing section, while the second unit controls two blending and one pasteurizing section. The third unit is a processing sequence run in manual. The PLCs are polled every three seconds, and the system responds rapidly to commands. We can input a command in Lookout and then watch while the system responds

While the system is running, Lookout communicates with unit one or two directing how to adjust preset counts for meters that tie directly into the PLCs. The data is then logged to a material usage database so Blue Bell can keep the proper amount of seasonal inventory. Also, with the easy-to-use graphical interface in Lookout, the lab can monitor all three blending operations at once. Operators use an HMI to begin the process of drawing raw ingredients and mixing them. When the process is complete, operators push a confirm signal in Lookout to verify that the batch has been made. Once Lookout stamps a batch as complete, it then informs Visual Basic that the batch is made, marks the batch as complete, and queues the next batch. We send the interface I/O to a Visual Basic application via a dynamic data exchange (DDE) link. Visual Basic, having had mixes input by lab personnel, then prepares batches that are loaded into I/O. Lookout then notifies Visual Basic when batches are completed, and Visual Basic records the raw material usage and the completion times data for the inventory system.

Benefits of Lookout

Lookout has been a key in maintaining the integrity of Blue Bell products. With the advent of Lookout, Blue Bell can manufacture three flavors without significant halts in production. Lookout helps minimize modification to internal information systems and keeps cost low because it integrates well with other applications.

With this flexibility, Blue Bell can import material usage and completion times data into the internal inventory system for easy bookkeeping updates. We used our Brenham, Texas, facilities as a pilot plant to modify our process. Now, with the success we have had with Lookout, we have implemented the system in our other plants in Broken Arrow, Okla., and Sylacauga, Ala. Overall, Lookout is an easy-to-use product that supports our commitment to quality as the scale of production increases.

http://sine.ni.com/cs/app/doc/p/id/cs-200