Home >End of the line for traditional PLCs in packaging?
End of the line for traditional PLCs in packaging?
11 February 2019
Over the last ten years there have been have significant increases in the speed and flexibility demands of packaging lines that are challenging the use of traditional PLCs and, therefore, legacy standardisation strategies. Martin Walder reports
The traditional Programmable Logic Controller (PLC) has dominated the global control landscape across food and beverage plants for the last twenty years from process to materials handling and packaging. Having just one manufacturer's range of equipment has brought a range of benefits to the End User lowering downtime and increasing efficiency – but things are changing.
Today, one the biggest focal point for investment in the food and beverage sector is in the packaging side of the business. You may ask why? Well, quite simply it’s because this is the most likely area to generate added profit.
In the UK, the basic products and processes for making our food does not change frequently. The only reason this would change significantly is if there were a seismic change in technology, such as the introduction of the freeze-dry coffee process in the nineties.
The biggest drivers in the packaging industry include: shelf ready packaging, maximising product shelf density, utilising safer and more sustainable materials, customisation of products and the use of lighter packaging for refills.
In food and beverage production, the largest proportion of factory labour resides in the packaging areas. This means greater saving, if automation and robotics can take over the repetitive tasks integrated on the factory floor. There is an ever-compelling case for the use of automation and robotics as access to low cost labour becomes more difficult, the minimum wage increases and there is more focus on health and safety at the same time the cost of the technology is reducing.
Whilst PLC based automated packaging equipment was commonplace twenty years ago, packaging equipment was often synchronised with mechanical cams and product picking done almost entirely by humans.
In 1999, the picker robot was introduced and was controlled by a standard automotive type of robot controller. This was able to pick, orient and place products from one location to another, running up to 150 moves per minute.
At the same time, the motion capability of a number of leading PLC manufacturers was beginning to change. Additional modules were added to the PLC backbone to control motion axes and as a number of axes and machine speeds increased, the CPUs continually needed upgrading to keep up and on top of the end machines.
In the 2000’s we saw many picking and packing lines with a combination of PLC’s and robot controllers each with their own programming environments but joined by a network.
In the last 5-10 years we have witnessed OEMs building or buying standalone mechanical robot arms and integrating PLC based motion control of the same type used to control the rest of the packaging line. Whilst the control systems are consistent they require multiple controller and often many control cabinets for the complex lines.
New generation control
Picking and packaging lines have come a long way. Manufacturers no longer have to convince end users to use them – and this is key. We’re witnessing increasing demands for faster lines that require multiple robots (3,4,5 feeding one wrapper) and sequenced motion axes. These need to fit into existing factories that have limited space and be fully IIOT enabled.
The traditional PLC based architecture becomes more and more limited as the number of robots increases – since fast robots each typically require one PLC system.
For this reason, I feel traditional PLC based control architecture will be phased out for this type of line in favour of a new generation of ultra-high-performance motion and robotic controllers, that also have PLC sequence capability. These controllers can sequence 120 high speed axes of motion across multiple robots and multiple machines.
Ultimately, not only do these controllers outstrip the PLC for this control, but they also offer full IIoT connectivity and benefit from a whole series of digital tools for remote tracking, monitoring, optimisation and remote services including the latest augmented reality support tools.
Schneider Electric’s compact PacDrive3 is leading the way in this technology and can be used to control a series of Schneider Electric picking robots and a wrapping machine all from the one controller. Furthermore, by using motors with integrated drive electronics panel space is kept to an absolute minimum - very compelling when updating brown field facilities.
Martin Walder is VP Industry at Schneider Electric