Wherever pressure sensors are needed, a solution can normally be found in the Keller product catalogue. However, there are often great benefits to optimising a product specifically for integration and use in complete existing systems. In addition to outwardly identifiable components such as housing parts or plugs, this also includes the inner workings of the sensor. Keller by Instrotech offers a large number of individual parts in-house, and establishes close working relationships with its suppliers, enabling them to make a wide variety of modifications with ease.
Shared expertise for the perfect sensor solutions
Keller by Instrotech’s customers are specialists in their field. They know the requirements and operating conditions best. Since 1974, Keller has been harnessing the potential of piezoresistive sensor technology to see numerous challenging projects through to completion. In all of these projects, a mutual exchange of expertise was essential to their success. Sharing Keller’s knowledge is what enables them to find the best sensor solution.
Even applications that may appear trivial at first glance can prove highly complex upon closer analysis. By taking the actual usage conditions of the sensor into consideration right from the outset, Keller can achieve major improvements in effectiveness and durability. This holds true whatever the application – from fill-level sensors in rainwater tanks to ultra-precise laboratory instruments, and even rocket science.
No matter the task at hand, expert advice from Instrotech’s sales engineers and developers is a vital piece of the puzzle. Together, Instrotech and Keller look at the requirements to determine the properties needed for flawless measurement. Armed with many years of experience, they take a close look at all the factors involved and their various interdependencies.
Measuring ranges and performance
First of all, they define the basic sensor specifications such as overall measuring range, accuracy, calibration to specific measuring points and units of pressure, or scaling of the output signal. Products with a digital signal output have additional factors that also need to be determined, such as sampling rate or signal resolution. The values defined at this stage form the starting point for selecting components.
Keller’s technical director, Bernhard Vetterli says, “We can make even the impossible possible, thanks to our technological expertise, longstanding experience and mastery of the many processes involved in manufacturing pressure sensors, coupled with a high level of vertical integration.”
Perfectly tuned to the ambient conditions
Another crucial requirement is considering the ambient conditions. Not only does this increase the service life of the sensor, but it is also an essential prerequisite for correct measurements. If the pressurised system operates with a large overpressure or with dynamic loads, the sensor design must be optimised for these particular demands. With some applications or neighbouring system parts, there is a risk of signal distortion or component failure due to vibration or shock.
Temperature also has a major impact on all materials and their resistance. Complications can be caused not just by extreme temperature values, but also by rapid changes in temperature. Another equally important factor is chemical resistance. The materials used for housings and seals must be carefully selected, otherwise they risk being damaged by aggressive media. External factors, such as petrol fumes, UV radiation, salt water ,or even microorganisms, can also cause problems. It is therefore essential that all relevant factors be considered. Of course, even finely-tuned designs still have limits, and additional protective measures may be needed.
Head of quality assurance at Keller, Stefan Fehr, adds, “Our experience has taught us that material and physics hardly know any limits when it comes to creating new challenges for us to solve.”
Mechanical design
When designing a sensor, all the above points must be taken into consideration. A device’s performance is heavily influenced by the sensor design, from the choice of the sensor chip and coupling medium through to the materials and production techniques used. In addition, customers may have particular requests concerning shape, size or pressure connections. Any specific requirements about the area of application must also be complied with, along with all the applicable legal regulations and standards.
Head of mechanical engineering, David Bollinger, says, “Customer-specific constructions are an important driver of innovation, and inspire us to develop new ideas and approaches to finding solutions. Ultimately, new findings are always incorporated into the further development and improvement of our existing product range.”
Electronics and configuration
The main function of the electronics is to prepare the measurement signal, and also possibly to save it and output it via a suitable interface. Customers can also request that application-specific calculations be integrated into the firmware, or ask for special device and software configurations. Once again, other requirements depend on the environment, such as extended lightning protection, EMC or explosion protection. Intrinsically safe products can also be specially configured to match the parameters of the customer’s overall system.
Electrical interfaces and connections
Digital interfaces can be configured for specific communication protocols, or modified to suit the customer’s needs. Meanwhile, analogue interfaces also continue to play a vital role in sensor technology. Keller is highly experienced in developing application-specific solutions based on both of these principles, including devices with light wave and frequency outputs. For electrical connections, the necessary plugs can be integrated into the design, while cable outlets can be specified by the customer.
Keller’s head of product management, Daniel Hofer, says, “The success of a project hinges on the exchange of information at the interfaces. We are committed to offering a wide range of protocols and electrical interfaces for seamless system integration and loss-free transmission of pressure values.”
Labelling
In addition to customer logos, it is also possible to have functional markings applied to the product, either employing laser inscription, or by printing information on labels. These may include part codes, serial numbers, data matrix codes, or guide marks. Customers can also specify a colour-coding scheme for the connecting wires. For consumer products such as manometers, a personalised design that includes the customer’s logo can be applied to the front panel.
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| Tel: | +27 10 595 1831 |
| Email: | [email protected] |
| www: | www.instrotech.co.za |
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