Adopting an integrated control approach for primary and secondary manufacturing processes through available automation solutions can deliver many benefits for food manufacturers – especially in terms of raising operational efficiency performance, improving production flexibility, lowering lifecycle costs and tracking product details for legislative commitments. Simon Ellam from Siemens Industry Automation explains more

Food manufacturing typically involves both primary and secondary manufacturing processes. Primary covers bulk material handling, mixing (often in batches), as well as continuous manufacturing. A secondary process involves the filling, packaging and final manufacture stages of products before onward delivery to the consumer via the retailers’ shelves.

Traditionally, we have seen different manufacturing philosophies supporting either the primary and secondary processes. Primary (or process manufacturing) concerns ingredients, liquids and powders being moved and mixed together using vessels and pipes.  Such processes require a highly intuitive and informative operator environment. To be able to understand and control a process that could be spread over a large geographic plant area and which has extremely limited or a lack of visibility, a distributed control system (DCS) or process control system offers the most effective solution.

Alternatively, when looking at the secondary or discrete manufacturing element, this will typically involve linking multiple filling and packaging machines to create a finishing process for the product.  Such an operating environment requires autonomous PLCs for the purpose of machine supply, together with small, non-complex HMI operator displays. As the workings of the machine are clearly visible, problems can be easily diagnosed by operators.  In essence we often see two separate control technologies in play within the same manufacturing plant.

However, as competitive pressures mount and seeking operational efficiencies become ever more crucial, it is clear that to support food manufacturing requirements, control system manufacturers have to offer a best fit for both operating environments and end user companies need to seriously examine the benefits integrated automation can bring.

This type of combined manufacturing environment is classed as ‘Hybrid’ from an automated control systems perspective. A ‘joined-up’ automation strategy to control a hybrid manufacturing environment is massively important in driving operational efficiency objectives across the many production processes that are inherent in the food industry.

In the past, integration could not be achieved between the process and discrete manufacturing environments because of the differences between the DCS and PLC/Scada architectures and associated hardware/software. But times have changed and currently a number of the largest control system manufacturers are offering a single equipment solution for both environments. In Siemens’ case all our hardware and software platforms can be used for both environments with just a differing engineering and operational philosophy placed on that platform.

Production flexibility

Through an integrated approach to the control of the process and discrete environments, major benefits can also be achieved by creating closer links between the shop floor and Enterprise Resource Planning (ERP) levels through a homogeneous approach to the adoption of manufacturing automation. A single database used to capture all manufacturing data offers a high level of flexibility to the end user when it comes to processing works orders and automatically cascading the required materials and manufacturing sequences down to the production line.

Automation technology solutions such as the S88 Batch Standard provides food manufacturers with a highly flexible and standardised way of producing differing products using myriad combinations of raw materials – whilst creating clear and proven provenance and repeatability for the end product.

Many companies often ‘de-couple’ the associated batch software from the process control system and have it handled entirely at the SCADA or visualisation layer. The use of PLC and SCADA for process control requires two engineering environments and the potentially troublesome ‘stitching’ together of these environments. This has traditionally provided limited flexibility for batch manufacturing, as well as requiring further engineering in both PLC and SCADA environments should any changes to batch structure be required.

However, a process control system or DCS ‘linked’ to batch control provides a single, tightly integrated batch manufacturing approach and changes can be performed in a single place which can then proliferate through the whole control system. This provides both operators and ensuing engineering tasks with a truly flexible foundation when it comes to the necessary and regular amendments and additions to SKUs that often occur within a fast changing market.

Finally, in modern manufacturing food manufacturers will often want to be able to track all the relevant details of how and when a product was produced. This type of information is generally required to be proven by legislative bodies for compliance purposes.  In such circumstances a tight integration of control system into the ERP level allows all the correct data and documentation to be in place without the need for time-consuming and unproductive paper trails.