40 n SENSORS AND ENCODERS February 2024 www.drivesncontrols.com Let’s talk about Teds The biggest challenge when acquiring data using sensors is understanding what you are measuring and getting the right sensor for the job. For accurate and meaningful measurements, engineers must be able to calibrate their sensors so that their measurements have traceability This means converting an electrical output, such as a voltage or current, to a measurement in engineering units. For example, in weighing applications, a measurement of 0mV/V could equal a mass of 0kg and 3mV/V could equal a mass of 100kg. This calibration information must be entered into the measurement device by an engineer. Many sensors cannot store calibration information. Instead, time-consuming manual calibration is needed. To do this, the sensor is fed with known inputs, and the electrical output for each is recorded. If there are many calibration points, it takes a lot of time and e ort simply to apply the known inputs. Furthermore, if an engineer uses the wrong measurement device to collect data, the mismatch could go unnoticed, adding human error to the process and costing valuable time and money. Teds-enabled devices can help prevent this. Teds (transducer electronic datasheet) are tiny memory chips that use a single-wire bus communication system. When integrated into a sensor, they can store information on the type of sensor being used, operating information and calibration details. This means that when a user connects a measurement device to the sensor, any setup information can be transferred automatically to the measurement device. This is great for identifying mismatches between tools and sensors, thus avoiding the risk of human errors. Furthermore, because all of the information is stored in the sensor, Teds-enabled sensors can be swapped easily without needing to recongure the system. Although a Teds-based system may incur higher upfront costs, the return on investment should not be underestimated. For example, the increased calibration options for Tedsenabled sensors save time during system conguration and avoid downtime because of erroneous data readings. Long-term thinking All Teds-enabled devices have a basic twopoint calibration which may be enough in most cases to minimise measurement errors. However, sensors that are non-linear over a measurement range may require multi-point calibration to achieve accurate measurements. Teds chips allow more calibration points to be stored in a sensor, improving the accuracy and precision of the data. So, while the sensor may cost more, the measurement data is likely to be extremely accurate. Moreover, measurement devices can be used with several Teds-enabled sensors, allowing readings to be taken from any sensor with a unique Teds ID at any time. By contrast, in non-Teds systems, measurement devices are tied to just one sensor. While most Teds-enabled sensors will have a predened template ID set up by the manufacturer, engineers can also collaborate with sensor suppliers to dene their own templates for enhanced sensor functions. For example, in load cells used to measure both tension and compression, di erent calibrations are needed for each direction. Furthermore, a sensor is sometimes used over a small part of its measurement range and more complex calibrations are needed to capture accurate data. Custom templates such as this can be designed by the manufacturer to give end-users much more exibility over the data they are collecting, and allow more data points can be taken at any one time. Sensing specialists, such as Mantracourt, can help businesses to develop their own proprietary Teds templates, which can be supported in their measurement devices. For example, there is a range of portable sensor displays that o er Teds support for up to ve extended calibrations, with any mixture of multi-point and polynomial functions. n Calibrating sensors can be time-consuming and costly business, which can be avoided by incorporating Teds (transducer electronic datasheet) chips in the sensors. Dr James Slader, deputy engineering manager at telemetry specialist Mantracourt, explains the advantages of upgrading legacy sensors to Teds technology. This portable display shows measurements from strain-bridge-based sensors such as load cells, providing Teds support for up to ve extended calibrations Teds chips simplify the process of calibrating sensors
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