Opened in June '96, the plant produces more than 200 products at capacities up to 20,000 pieces per hour - about three and one-half times the capacity of the firm's former facility. Teeny is best known for its patented Pocket Bread, the Middle Eastern pita break introduced to the U.S. in 1964 by Sam and Minerva Teeny.

"We needed more space, but we also wanted to improve our production process...while maintaining our high standard of quality," says President Rick Teeny. "We added variable-speed motor control and integrated the controls with OEM equipment so we could communicate on one network. This enables us to coordinate production throughout the plant. In the long run, the new system will dramatically reduce our cost per piece."

Small size was one reason why Teeny selected the Bulletin 160 SSC. The controller measures only two and one-half by five inches, allowing Teeny to fit as many as 24 controllers into a single cabinet and reduce expensive wiring while saving space.

The SSCs regulate the speed of AC motors driving conveyors on both the sheeting and baking/cooling lines. Variable speed control matches recipe requirements and time/temperature relationships while baking and cooling different products.
Each recipe, for example, calls for dough of slightly different thickness and shape. On the sheeting line, Bulletin 160 SSCs synchronize the speeds of conveyor and rollers to sheet dough to specified thickness and weight before it reaches the cutting station. Accurate speed is critical because the dough will not bake correctly if it isn't the right thickness.

Prior to proofing, precise conveyor speeds synchronize dough transfer to trays that carry the dough through the proof box. Uncoordinated conveyor speeds can cause product to drop to the floor. The SSCs coordinate conveyor speeds to minimize discarded product.

After proofing, the trays are loaded onto the oven line and the dough transferred from the trays to the oven conveyor. Transfer speed depends on the product. Pizza bread, for example, is larger than Pocket Bread products and requires a slower transfer speed. Product transferred at the wrong speed will either stick to the tray or transfer unevenly, causing damaged product. Bulletin 160 SSCs match conveyor speeds to product, reducing waste.

An Allen-Bradley 1336 PLUS variable-frequency AC drive controls conveyor speed in the plant's two-story I.J. White spiral cooler/freezer, which has belt capacity for up to 6,000 pieces of pocket bread. Cooling time for pocket bread is typically 20 minutes; freezing time 30 minutes. This drive "acts as a timing function, [controlling] the length of time it takes the product to go through the cooling rack and achieve the desired temperature," says Teeny Engineering Manager Jim Georgioff.

The ability of a single Bulletin 160 SSC to control two motors minimizes slack time on a 180° conveyor turn, Georgioff adds, as well as on two S-curves in the conveyor that returns empty pans from the baking line to the sheeting line.

DeviceNet links all control devices, allowing them to communicate with each other and allowing operators to monitor and control the line from any of three Allen-Bradley PanelView operator-interface terminals on the plant floor. It also transmits information like current status, speed, level and temperature of the motor controllers to Georgioff's terminal, where he can "monitor the entire process, download information, and identify where fine-tuning can be made."

DeviceNet incorporates diagnostic functions that immediately notify operators of line problems, and self-diagnostics for each device. This minimizes maintenance and troubleshooting time. "You don't need background in programming to locate the problem," says Tom Hatch of C-Tech Services, the systems integrator who helped Teeny Foods upgrade its system.

Easy to install and program, DeviceNet contributed to quick startup of the new plant. Teeny Foods lost only three days moving into its new location. DeviceNet dramatically reduced the wiring that would otherwise have been needed to integrate 34 controllers.