Autonomous machines and the Internet of Things have brought sensors to the forefront of electronics design.
As the Internet of Things continues to expand and more applications feature autonomous functions, sensors have become an integral part of many electronic products. They capture the information that brings capability, autonomy, and precision to products in markets ranging from transportation to consumer products to medical diagnostic and treatment equipment. Every sensor depends on a connector and cable assembly. In recognition of the integral role these components play in modern systems, several connector companies are fine-tuning their offerings to offer products that optimize sensor placement in new designs, and a growing number of connector companies are acquiring sensor companies to bring that expertise in house and develop new products in tandem.
“The sensor market is very diverse right now, and that’s opening the door for companies to offer whole solutions for engineers who need to solve issues involving a sensor. A challenge might start with a sensor but looking at it as part of an integrated system brings opportunities to come up with a series of solutions to make the whole package more successful,” said Brian Wellhouse at TTI Inc, a distributor that has seen demand for sensors rise exponentially.
We talked to Wellhouse and Josh Slater at TT Electronics, a company that has one of the industry’s largest selections of sensor products, to find out more about how sensors are impacting the electronics world.
What types of sensors does your company offer?
Josh Slater at TT Electronics: Optoelectronic assemblies, pressure sensors, temperature sensors, flow sensors, level sensors, position sensors, and steering sensors (EPS sensors), among others.
Brian Wellhouse at TTI Inc.: We offer all different technologies, including pressure, force, flow, motion and position, temperature, humidity, and optical. We have a wide selection of sensors from companies like TE Sensors, Sensata, Omron, Murata, and Honeywell.
When did the company make sensors a priority, and what spurred that move?
TT Electronics: Sensors have been a prioritized part of TT Electronics’ portfolio for over 50 years, with a specific focus on providing our customers with value-add sensor assemblies to solve their most challenging problems.
TTI Inc.: Sensors have been a part of our business for a very long time, but they have recently become a much more important part of our offering. The sensors part of our business is growing by 25% a year. It’s huge. Application usage of sensors is increasing, and sensors were a door-opener for us with engineers. It’s a great product that engineers can think about “What’s next” for their application. Efficiency, added features, or just adding more data to its function can all be done with sensors.
What role do connectors and cable assemblies play in maintaining the reliability of sensors?
TT Electronics: With the majority of critical solutions, sensors are often fitted with highly reliable connectors. To the user, all the technology may appear to sit within the sensor, but quite often, the only item the user interacts with is the connector. Any fault picked up within the connector impacts the sensor solution and could lead to the sensor being labelled as a “bad product.” That makes the connector choice within the application that much more important. TT Electronics has the capability to supply both the sensor and the connector individually or as a complete unit with the quality of both products guaranteed.
TTI Inc.: Quality connectors and cables are especially important in harsh environments. High vibration in factory automation or transient blocking unit applications have a lot of off- board sensors, so the connector reliability can be an issue, just as soldering can be for a PCB sensor. We are looking at whole systems with every customer to make sure they are getting the most compatible components. We could just sell sensors, but that’s not really how it works with this product. You want the customers to understand safety, efficiency, and compatibility. You want them to understand why we choose this one and not that one, so they get the best fit and the most functionality from that choice.
Sensors such as those used in vehicles are exposed to debris, moisture, etc. What can be done to minimize that impact?
TT Electronics: An ordinary passenger car might travel 160,000 km over its entire lifetime whereas some commercial vehicles are expected to cover more than 400,000 km in just three years. Moreover, the operating environment in a commercial vehicle is more prone to noise and vibration, which places an even greater demand on the performance and reliability an electronic power steering (EPS) system must deliver. The heavier steering loads presented by commercial and off-road industrial vehicles require a higher power assist. Steering column mounted EPS units typically produce a force of about 5 kN. Moving the EPS closer to the wheels to drive either the pinion shaft or steering rack can increase this to between 5 kN and 12 kN but will subject the EPS to higher temperatures and vibration. Larger vehicles are likely to require even greater force, at least 15 kN and potentially much more for the most demanding off-road applications. EPS systems for such vehicles will need to operate from higher voltages, e.g. 42V, and be capable of delivering output powers greater than 3 kW.
A better solution is to use non-contacting position and torque sensors, based on either magnetic sensing principles, and mount them on the steering rack. With these, the system is less affected by vibration, which reduces noise and increases reliability. TT Electronics offers the Magnetorque Plus steering sensor that is specifically designed for rack-based EPS systems and can be customized to fit larger shafts such as those found in trucks, buses, and off-road vehicles. This sensor has been rigorously tested to meet the vibration challenges posed by commercial vehicles.
Non-contact position and torque sensing can both be implemented using Hall effect technology, which detects the influence of a magnetic field on a current-carrying conductor and generates a voltage difference across that conductor but transverse to the current flow. Hall effect sensors are implemented as integrated circuits where the effect of the magnetic force on the charge carriers in the semiconductor can be measured as an output voltage of the chip.
TTI Inc.: Using a quality product to start with makes all the difference. TTI carries the top of the line suppliers for a reason and our sensors are made to withstand these environments. Also, it’s about using the right sensor technology. If there is high debris, we’d want to stay away from optical solutions, for example. Hall effect sensors would be better suited to that type of application.
How can connectors support data integrity in sensor-involved systems?
TT Electronics: A reliable, robust, and efficient connector ensures that both the integration of the system is easily made, a secure connection is established, and data integrity is not compromised. TT Electronics MIL-DTL-26482 (AB05) and MIL-DTL-5015 (ABCIRH) connectors ensure that, even within the harshest of environments, the data collated is efficiently maintained and easily retrievable.
TTI Inc.: This goes back to a lot of the environmental issues. It’s important to use the right connector, not the lowest cost one. If you have a connector that you prefer in your system that has a proven record, many manufacturers can configure those assemblies to incorporate that connector, so take advantage of that.
How much stress do sensors place on an electrical system in terms of heat generation, energy consumption, and space? What can be done to minimize that?
TT Electronics: Hydraulic power-assisted steering is steadily being replaced by EPS systems in many new vehicle designs. In the passenger-car market, the use of electric motors to drive the steering rack is largely motivated by the resulting, albeit small, improvement in fuel economy. EPS also contributes to greener vehicle end-of-life by having no hydraulic fluid to dispose of. It also continues the inexorable trend towards computer-controlled drive-by-wire systems, which started with anti-lock braking and traction control and is now taking us towards fully autonomous vehicles. Despite the poor experience of early EPS designs, with criticism of their lack of “feel,” it is generally accepted that refinements in electric power steering systems, with improvements in sensor and control technology, have overcome such concerns.
TTI Inc.: I think that the sensor has been optimized for the system so that we are seeing more options on the lower-level consumption, and sensors with multiple sensing capabilities (sensor fusion, for example), in which temperature and humidity can easily be put into one component. Minimizing stress could mean really just updating the sensors in your system. Most of the new development in sensor fusion has been over the last five years. So those older technologies are still working great, but new products have been made to mitigate the energy consumption or really just provide an optimized solution.
Look back two years: What can sensors do today that they couldn’t do in the recent past?
TT Electronics: The adoption of electric power steering in passenger vehicles is proceeding apace, but its adoption in heavier commercial and industrial vehicles has been slow. Such applications, and especially the industrial off-road class of vehicle, present particular challenges for EPS systems, which need to achieve reliable, long-life operation in harsh environments and yet still deliver precise and responsive control. Increased system accuracy is now possible with customer programmable torque offsets, and custom torque output slopes are available along with other custom design options. The integrated approach is smaller, lighter, and more cost-effective than alternatives using two separate sensors, while the fully calibrated solution simplifies the route to EPS system design for the harsher and tougher requirements of larger vehicles.
TTI Inc.: I don’t know if it’s about the function as much as it is in the packaging. Temperature sensors, for example, are still sensing temperature, but when we add a humidity sensor to the same package the accuracy jumps and makes a better part for the system, saves some space on the PCB, and lowers the current consumption. So overall, same parts, in improved packaging, and many times at a better cost.
What new functions do you predict they will have in the next two years?
TT Electronics: Commercial and industrial vehicle applications are likely to adopt autonomous or semi-autonomous driving technology sooner than regular road vehicles, making EPS a prerequisite. Long-haul freight delivery is one such early candidate. An area where it is already happening is in factories and warehouses, where forklift trucks are rapidly being replaced by driverless vehicles operating entirely under computer control.
TTI Inc: I see more wireless solutions coming out. With Bluetooth and other wireless modules shrinking in size, it allows them to be embedded within the sensor package.
This is a quickly evolving area. What does your company do to stay ahead of or support sensor development?
TT Electronics: TT Electronics continually invests in our R&D, operations, facilities, and capabilities. We’re expanding through a series of acquisitions, adaptations to market demands, and the development of advanced electronics capabilities. We focus on building leading positions in areas of the market where there are structural growth drivers and the proliferation of electronics is driving demand for our solutions. In October, we are debuting the latest generation in the Magnetorque steering sensor family, the MT4. It is highly accurate, reliable, and affordable.
TTI Inc.: As a distributor, we look to our customers. I meet with engineers across the country who are interested in sensors but may not be able to find the perfect fit. We take that back to our suppliers, and that can lead to new product developments. With so many sensors being configurable or customizable, I try to keep them in standard packages, but find a part that fits their system perfectly.
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