Tag Archives: Industry 4.0

Modern RTD-Based Sensors

The popular belief is to not fix things that aren’t broken. The idea is to not tamper with something performing reliably and proving its worth. This advice aptly applies to circuit designs using RTD sensors that efficiently and quietly measure temperature in industrial manufacturing facilities worldwide.

However, in meeting the requirements of Industry 4.0, where smart factories are the norm, it is now evident that the current RTD sensors in use are not fitting the purpose. Automation engineers today want industrial temperature sensors to be of smaller form factors, flexible with communications, and capable of remote reconfigurability. Incumbent solutions, sadly, are unable to support them. However, it is possible to easily redesign these sensors to equip them with the necessary features to meet the new industrial design.

The RTD industrial temperature sensor translates temperature, a physical quantity, into an electrical signal. The typical range of such sensors is between -200 °C and +850 °C, with a highly linear response across it. RTDs commonly use metal elements like copper, nickel, and platinum. Among these, PT1000 and PT100 platinum RTDs are the most popular. While an RTD can use either two, three, or four wires, the 3-wire and 4-wire versions are the most popular. Being passive devices, RTDs require an excitation current for producing an output voltage. A voltage reference generates this current, with an operational amplifier acting as a buffer for driving the current into the RTD, which produces an output voltage signal varying in response to changes in temperature. The voltage signal may vary from tens to hundreds of millivolts depending on the type of RTD in use and the measured temperature.

An AFE or Analog Front End conditions and amplifies the low amplitude voltage signal from the RTD before the ADC or Analog to Digital converter digitizes it. A microcontroller runs an algorithm over the digitized signal, compensating for any non-linearity in it. The microcontroller then sends the processed digital output to a communications interface for transmission to a process controller. A typical implementation of the AFE is by a signal chain of components with each performing a dedicated function.

This discrete approach requires a large PCB or printed circuit board for accommodating all the ICs and power and signal routing, setting a minimum size for the sensor enclosure. Rather, modern RTD-based sensors use a superior and more minimal approach—the AD7124-4, an integrated AFE.

The AD7124-4 is a compact IC in a single package. It includes a multiplexer for accommodating multiple-wire RTDs, a voltage reference, a programmable gain amplifier, and an ADC using the sigma-delta operating principles. The IC has the capability to provide the necessary excitation currents for the RTD. The entire arrangement effectively replaces five of the signal-chain components from the traditional setup. Not only does this significantly reduce the amount of board space necessary, but it also enables the sensor to use a much smaller enclosure.

Next comes the communications interface. Modern RTD-based sensors typically use the IO-Link which eliminates the use of expensive ASICs for implementing specific network protocols. IO-Link is a 3-wire industrial communications standard for linking sensors and actuators with all industrial control networks.

Future Factories with 5G

The world is moving fast. If you are a manufacturer still using Industry 3.0 today, you must move your shop floor forward to Industry 4.0 for being relevant tomorrow, and plan for Industry 5.0, for being around next week. 5G may be the answer to how you should make the changes to move forward.

There has been a sea of changes in technology, for instance, manufacturing uses edge computing now, and the advent of the Internet of Things has led to the evolution.

At present, we are in the digital transformation era, or Industry 4.0. People call it by different names like intelligent industry, factory of the future, or smart factory. These terms indicate that we are using a data-oriented approach. However, it is also necessary to collaborate with the manufacturing foundation. This approach is the Golden Triangle, based on three main systems—PLM or Product Lifecycle Management, MES or Manufacturing Execution Systems, and ERP or Enterprise Resource Planning.

With IoT, there is an impact on the manufacturing process, depending on the data collected in real-time, and its analytics. Of course, it complements existing systems that are more oriented to the process. Therefore, rather than replace, IoT actually complements and collaborates with the existing systems that help the manufacturer to manage the shop floor.

IoT is one of the major driving factors behind the movement that we know as Industry 4.0. One of its key points is to enable massive automation. This requires data collection from the shop floor and moving it to the cloud. On the other end, it will need advanced analytics. This is necessary to optimize the workflow and processes that the manufacturer uses. After the lean strategy, there will be a kind of lean software, acting as one more step towards process optimization within the company and on the shop floor.

However, manufacturers will face several challenges as they grow and scale up their IoT initiatives. These will include automation, flexibility, and sustainability. Of these, automation is already the key topic in the market—the integration of technologies to automate the various manufacturing processes.

The next in line is flexibility. For instance, if you are manufacturing a product in a line, it takes a long time to change that line for making another product.

The last challenge is rather vast. Sustainability means making manufacturing cost-effective by improving the processes and the efficiency of the equipment. It may be necessary to minimize energy consumption, and decrease lead time and manufacturing time. It may involve using less material and reducing wastage.

With the advent of 5G, manufacturers will be witnessing many new and exciting possibilities. The IoT of today has two game-changers that will affect the IoT of the future. The first game-changer is 5G, while edge technology is the other. Ten years ago, IoT was only a few devices sending data to the cloud for human interaction and analytics.

Now, there has been a substantial increase in the number of devices deployed and the amount of data traffic. In fact, with the humongous increase of data, many a time, it is not possible to send everything to the cloud. While 5G helps with the massive transfer of data, edge computing helps standardize the data and compute it locally, before the transfer.