Automation control vendors are targeting simpler packaging machines with technology solutions that create a balance between the need for higher performance and the lower controls budget that entry-level, lower axis count OEM packaging machines require. Increasingly, these solutions are finding ways to distribute intelligence and safety features into devices as a way to add network-type sophistication without the full overhead of a more complex controls approach.
One example of this trend shown at interpack 2014 featured an equipment demonstration of B&R Industrial Automation's fast response I/O slice, which can close the control loop in as little as one microsecond. Using the I/O slice working on a sensor, the demo had a white ball and a black ball being shot through the air. After identifying each ball in flight, the reject station would then fire a burst of air to redirect the ball to an appropriate bin.
By being able to respond so quickly, compared to a normal reaction time that might be hundreds of microseconds, the idea is to reduce the distance that the product travels between sensing and being rejected. In packaging applications, this might make the machine footprint smaller and cycle rates higher.
Distributed intelligent components
"Using an FPGA on the I/O slice adds intelligence and allows it to be its own processor which can be programmed in IEC 61131 within the Automation Studio software environment" John Kowal, director of business development at B&R, told Design News. "Instead of the signal being transmitted back to the PLC for processing, everything takes place within the I/O slice. More control is being distributed down into small, simple devices such as an I/O slice."
For line-oriented systems such as packaging systems where cycle times are extremely important, the technology offers a key throughput advantage. Kowal said a packaging machine manufacturer at the show told him that their wrapper machine is often going so fast that, if there isn't any product available, the system will still "wrap" and create an empty film. The speed of the process is preventing a no product, no fill option, and, if a product is rejected, the system will often reject three to five products to make sure the one defective product is removed.
"With the faster I/O slice technology, it's now possible that product rejects can be more immediate and the product doesn't travel as far before it can be removed from the line," Kowal added. "The one microsecond response rate, even though it sounds like something that wouldn't be needed if it was possible, is useful in practical applications. This is especially true in packaging systems where products are rapidly moving through a line-oriented process. Flow wrappers processing bite-size candy, for example, may be doing as many as 1,400 products per minute."
The keys to B&R's reACTION technology are that it combines centralized software administration with distributed program execution. It can be used for both low-end and high-end systems, and provides a fully integrated system using open IEC 61131 technology. The data exchange between reACTION I/O modules and the PLC in a typical system uses standard process variables.