Using Raspberry Pis to Collect Manufacturing Data

Ever since the advent of programmable logic controllers (PLCs), manufacturing engineers have been trying to find more reliable ways to improve production efficiency through data monitoring and management. The Raspberry Pi and other programmable logic controllers have reduced the cost of these pieces of hardware and because of their flexibility, they provide a wonderful basis for the development of devices for collecting manufacturing data.

The History of Manufacturing Data Collection

In the early days of PLC development, plant automation was also on the rise, as engineers found that they could automate complete sections of their process with the press of a key. PLCs were ideal for plant usage as they could stand up to a lot of environmental stresses that would have led to the demise of any comparable system made up of switches and wires. Data collection in many companies gives them a basis for their competitive edge against their rivals. However, because of the technological know-how needed to create and maintain these systems, they remain very complex and sometimes proprietary solutions. While investing in these systems do mean a more efficient production cycle, their costs can severely hamper a company’s bottom line. Thanks to the Raspberry Pi, PLCs that perform the same tasks as the expensive, proprietary hardware are now available to just about anyone at a fraction of the cost and complexity.

Ease of Use

The Raspberry Pi has a pretty good reputation for usability and that status stems from a number of different factors. Firstly, thanks to the single board on the system, the Pi can effectively create its own singular interface. The easy-to-use UI can allow for any member of staff within a company to quickly and easily access the data collected. The Pi also allows for storage of collected data on an external database via Ethernet. With a little skilled manipulation of code and with libraries such as Data-Driven Documents in JavaScript, a very stylish human-readable output can be generated quickly and accurately. Don't forget that developers need to be fully aware of the numerous industry-specific regulations concerning data collection. Understanding policy enables you to stay compliant with product liability laws, regulations, legislation, and legal text.

Multiple Applications

The reason the Pi is such an exciting development is because of how easy it has become to apply PLCs to almost any manufacturing process. Heatworks Technologies Inc. have developed a Raspberry Pi system to deal with data collection from test stations dealing with water heaters. In this system multiple different types of PCBs are integrated together, each one collecting a specific input. With a MOSFET board, the system can also be adapted to deal with output in order to control tests. This demonstrates that the Pi can be used in a most unlikely manufacturing situation and opens the door for its application in fields that haven't yet realized the benefits a PLC can provide.

Even More Options

ThreeML has recently introduced a series of modular boards built on a modified Raspberry Pi system called the Rhubarb. This system can be built to take inputs from 4 - 20 mA or 0 - 10V DC and can be used to send outputs making it ideal for a simplistic version of process control. Alternatively, an Arduino Mega input module can be used which allows for Ethernet I/O capability as well as serialization of data into JSON — something that is quite remarkable for the technological limitations of such a device.

Retail PLC usage, at least in these handfuls of cases, make for a compelling argument towards replacing complicated technologically advanced controllers with a series of smaller, more easily accessible PLCs. However, it overlooks some of the background work that the professionally produced processing systems do and while the Raspberry Pi is indeed an innovative system, the truth is that it is mostly a novelty when it comes to process controllers for large plants. On the bright side, it provides a very useful learning platform for staff as well as a platform which a company can build upon in order to produce in-house data collection and processing systems of their own.