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Home>AUTOMATION>Sensors >Making better sense of sensors

Making better sense of sensors

03 January 2015

Automation is at the heart of modern life, with the ability to provide effective use of valuable resources across the globe. Heiko Luckhaupt, category marketing manager, Automation & Control, at RS Components looks at the important role of sensors in this sector

Although the Internet of Things is currently being held up as perhaps the biggest thing ever, it’s relevant to point out that a major part of what will be the IoT is already, itself, a major horizontal market – automation. Industrial, process and factory automation is enabled by technology that has been evolving since before the semiconductor age, with a long history of being at the forefront of technological innovation. It enables all of the major industries that make modern life possible, such as energy, food, steel, paper, water and more. With a fundamental dependence on technology and the discipline to employ it reliably and effectively, it also follows that it will be one of the first markets to take full advantage of the IoT.

It is already apparent by the level of control that can be achieved, coupled with the more recent innovation of remote access and monitoring. This is, of course, enabled by global connectivity but more importantly its implementation relies on the development of more sophisticated and secure devices designed specifically for the harsh conditions present in almost every form of automation.

Developing devices suitable for these diverse applications requires a focus on three main aspects: data collection, signal conditioning and control. In automation, data is ultimately represented as a measurable electrical value comprising current, voltage and resistance, which may represent any number of physical properties such as temperature, vibration, rotational speed or strain. The level of accuracy and stability during signal acquisition is perhaps the most critical stage in process control, as any error introduced here will propagate throughout the system. Because of that it requires special consideration, with particular attention to temperature-dependent artefacts such as drift or offset, as stability over time is crucial in process control.

Sensors typically generate incredibly small signals


Many of these elements are particularly apparent in the sensor used, but the electronic interface to that sensor and its subsequent signal conditioning are aspects where system integration directly influences the quality of results. Sensors typically generate incredibly small signals, which means any unwanted ‘noise’ introduced at any stage must be identified and either removed or compensated for. Signal conditioning under these conditions represents the greatest challenge for system developers, something specialist supplier PR electronics understands; it develops and supplies signal conditioning and process control devices to all industries and holds a wide range of globally acknowledged industry approvals.

All automation installations can be described as ‘unique’ in their specific requirements and to meet this demand PR electronics offers a range of Temperature, I.S. (Intrinsically Safe), Communication, Multifunctional, Isolation and Display devices in four main formats: DIN Rail, Sensor Head, Panel and 11-Pole Socket. Together with its extensive quality management certification and compliance with globally recognised safety standards, this breadth makes PR electronics’ range (now available through RS Components) suitable for all automation/control applications.

Remote Control

A fundamental element of automation and control involves moving seamlessly between the analogue to digital domains, allowing sensor data to be used effectively. A significant advantage of data in a digital format is its relative immunity to noise; another important benefit is the ease with which that data can be distributed or accessed. Remote monitoring and control are becoming an integral part of automation and to support that manufacturers are developing devices such as the PR4511; a detachable display module that also adds Modbus RTU RS-485 serial communications to all current and future 4000/9000 units from PR electronics.

This device can convert a wide range of sensor and other analogue signals acquired — such as uni- and bi-polar mA/V signals, potentiometers, Lin, R, RTC and TC — to a Modbus communication line signal. In addition, when used with a 9000 device, it can convert any signal coming from or going to an intrinsically safe classified area to a Modbus network. It can be configured over a Modbus channel, as well as through its front panel, which houses the display.

Key Points

  • Developing devices for automation applications requires a focus on three main aspects: data collection, signal conditioning and control
  • Sensors typically generate incredibly small signals, which means any unwanted ‘noise’ must be identified and removed or compensated for
  • Moving seamlessly between analogue to digital domains, allows sensor data to be used effectively