Stand-alone, in-line or integrated? How your IO-Link amplifier choice can make all the difference
A BRIEF HISTORY OF SENSORS AND AMPLIFIERS
Things are changing in the world of measurement technology
For decades, traditional measurement chains for mechanical quantities including force, weight and torque have relied on the same setup – a passive strain gauge-based sensor, a sensor cable and an external instrument. The sensor and instrument must be connected (and the instrument parameterised) before measurement can begin. While this type of setup has worked well in industrial environments, it also demands specific requirements including a precisely controlled supply voltage, suitable low noise amplification for the sensor signal, and cables suited for strain gauge bridges to connect amplifiers and sensors. These cables also need shielding to avoid interference and ensure reliable measurement under critical circumstances. The next step in the market was the development of force and strain sensors that overcame the traditional setup by integrating analogue amplifiers, providing standardised and robust industrial signals with outputs of 4 – 20 mA or 0 – 10 V. However, as measurement technology evolves, we are witnessing a shift toward increasingly digital solutions in modern sensors. Microelectronics with new, more compact components make it possible to design in-line amplifiers (where instrument and sensor are hardwired), or even integrate the digital amplifier directly into the sensor as an integrated amplifier. For both in-line and integrated amplifiers, components form their own measurement chain, ready to measure right away. These types of setups are further enhanced by the addition of IO-Link – a modern, cost-effective interface that can be used for bidirectional data transfer with the sensor.
Here, we explore the differences between stand-alone, in-line and integrated amplifiers, and demonstrate how HBK’s innovative in-line and integrated IO-Link amplifiers simplify your measurement chains, improving precision while reducing your costs. We’ll also explain why integrated amplifiers are the preferred choice for tapping into the full potential of IO-Link technology.
THE DIFFERENCES BETWEEN STAND-ALONE, IN-LINE, AND INTEGRATED
Before deciding what setup to choose for your measure- ment chain, it is important to understand the differences between each type of amplifier.
Stand-alone amplifiers
Stand-alone amplifiers follow the traditional configuration of an amplifier and sensor as two separate components, as seen in the diagram. As stand-alone amplifiers are not pre-assembled, they require setup and adjustment before they can be used to measure any mechanical quantities. This can create a range of challenges for users, such as:
• The need for wiring to connect the amplifier and sensor
• Manual connection and parameterisation of the amplifier and sensor – this may involve connecting the components to a PLC, or even soldering the two components and wires together
• An increased risk of errors, such as human mistakes when manually entering incorrect values
In-line amplifiers
Unlike the setup for stand-alone amplifiers, the sensor and in-line amplifier consists of one unit, hardwired via a cable for a fixed connection. In-line amplifiers are the preferred choice for applications that require physically small sensor sizes (which do not provide enough space for integrated electronics), or when electronics should not be placed next to the sensor – for example, for applications using high temperatures.
Integrated amplifiers
As seen in the picture below, the U10M force transducer has an integrated amplifier. Because high-precision sensors are typically larger, there is enough space to integrate the amplifier. Integrated amplifiers, when combined with high-accuracy shear-web sensors, provide the most precise and reliable solution for a wide range of measurement tasks in production and monitoring. They are particularly valuable in assembly lines, end-of-line testing, and other industrial operations where precise measurements and rapid deployment are essential – whether within production environments or for certain testing applications. Examples include battery cell packaging, monitoring and controlling welding processes, and force or displacement control in joining processes.
THE BENEFITS OF IO-LINK: COMPARING IN-LINE AND INTEGRATED AMPLIFIERS TO STAND-ALONE AMPLIFIERS
1) Plug-and-measure
One of the major downsides of stand-alone amplifiers is the need for manual setup and adjustment before use. In-line and integrated amplifiers, such as those in IO-Link sensors from HBK, overcome this challenge by arriving pre-configured as a complete measurement chain. When connected to an IO-Link master, IO-Link sensors immediately provide readings in the correct physical units – such as Newton, kg, or Nm – without needing to enter parameters manually. This plug-and-measure functionality eliminates setup errors that can occur with traditional stand-alone amplifiers, and significantly reduces installation time. Instead of manually inputting sensor parameters into software, users can simply connect the sensor to the IO-Link master and begin measuring right away.
2) Improved precision and reliability
There are multiple different ways that both in-line and integrated amplifiers ensure consistent accuracy for their measurements. For instance, unlike stand-alone amplifiers, integrated amplifiers digitise signals at the source. As integrated amplifiers are already built into the sensor, this eliminates any cable effects of electromagnetic (EMC/EMV) interference. To provide even more advanced signal processing, HBK sensors feature adjustable Butterworth and Bessel filters to suppress noise and enhance signal clarity for consistent accuracy. Beyond electromagnetic interference, integrated amplifiers also digitally measure and compensate for temperature fluctuations in their surrounding environment. This minimises the impact of temperature changes on data collection, helping to ensure highly accurate measurements. Another way in-line and integrated amplifiers differ from stand-alone is in their linearisation functions. For instance, sensors with integrated amplifiers feature built-in digital temperature compensation, which significantly reduces measurement uncertainty and minimises sensor non-linearity, improving overall accuracy. Integrated amplifiers also feature a true game-changer for measurement precision and reliability – sensor health monitoring. This involves continuous diagnostics for static and dynamic forces, overload detection and operational limits, as well as temperature and environmental conditions. All of these technical limits are stored within the sensor itself. When the sensor detects that a limit has been exceeded, it alerts users with a warning before any critical failure can occur, allowing operational personnel to make any necessary adjustments immediately.
3) Cost efficiency
One of the most compelling benefits of in-line and integrated amplifiers is their cost-effectiveness. By eliminating the need for expensive measurement cables, and cabinet space, integrated amplifiers reduce the number of required components. This not only reduces the overall component cost but also results in a more compact and economical solution. With fewer components and simplified wiring, the setup time for integrated amplifiers is much faster, resulting in lower installation costs. For instance, sensors can easily be connected with an IO-Link Master via an M12 connection cable. This simple plug-and-play setup reduces labour costs even further by minimising the time needed to educate and train personnel. Since integrated and in-line amplifiers require no adjust- ment during installation, troubleshooting becomes much easier. Users can access the sensors directly from the control level for basic checks. This rapid deployment saves valuable production time and delivers long-term cost savings throughout the product life cycle.
4) Environmental and operational advantages
In integrated amplifiers, digital signal transmission eliminates the vulnerabilities associated with analogue signals. This resilience to electromagnetic (EMC/EMV) interference ensures consistent performance in environments with high electromagnetic activity. The resistance of integrated amplifiers to electromagnetic signals is particularly beneficial in environments with high electrical power consumption – such as factories – or when operating near sources of electromagnetic interfer- ence like inverters, electric motors, or digital devices. Integrated amplifiers are designed to withstand mechanical stress, vibration, and wide temperature ranges without performance degradation. Like their passive counterparts, they undergo the same rigorous type testing, providing durability in harsh conditions. Their robust environmental sealing enables reliable operation even in the most demanding industrial settings.
5) Additional functionalities
With the built-in statistical functions of the in-line and integrated amplifier, features such as minimum and maximum detection, span detection, and measurement statistics are processed directly within the amplifier. This saves expensive computational power in the programma- ble logic controller (PLC), which in turn reduces ongoing operational costs. Two independent limit switches are also available. In accordance with the IO-Link standard, the sensors feature hardwired digital outputs, allowing you to use the limit switches via a 24 V signal.
UNLOCK THE FULL POTENTIAL OF IO-LINK WITH HBK’S INTEGRATED AMPLIFIERS
Integrated amplifiers offer you the greatest benefits for your measurements. At HBK, we are revolutionising the world of measurement technology with our unique approach to integrating sensors and amplifiers into a single, calibrated unit. The seamless integration of the sensing element, signal processing and IO-Link interface is designed to function at the field level, including compatibility with PLC fieldbus systems. HBK’s smart sensors represent a fundamental shift from traditional measurement chains, which often rely on stand-alone amplifiers and manual adjustments. Instead, our true plug-and-measure design offers an unparalleled level of simplicity and reliability. With our proprietary sensor technology, we can help you transform your industrial operations for the better. With innovations such as digital temperature compensation, enhanced signal processing, built-in limit switches, comprehensive statistical functions, and robust sensor health monitoring, HBK continues to redefine the bounda- ries of measurement technology. These features not only improve performance but also provide users with a level of simplicity and reliability that is unmatched in the market.
Digital temperature compensation
Unlike traditional analogue methods, which struggle with non-linear temperature variations, our proprietary digital temperature compensation effectively handles these variations, significantly reducing temperature-related errors. This innovation ensures higher accuracy in measurements, providing a substantial advantage in applications requiring precision under varying thermal conditions.
Digital signal transmission and processing
By eliminating the reliance on analogue transmission, our technology removes the amplifier’s susceptibility to electromagnetic interference. This results in cleaner signals and therefore more accurate data. In addition, our smart sensors use high-precision linearisa- tion and filtering, including Bessel and Butterworth filters, to further reduce noise. For example, HBK’s U10M sensors have reduced linearity errors from 0.035% to less than 0.005% – a transformational improvement to the accuracy of measurement technology.
Statistical functions
HBK’s smart sensors embed statistical functions that measure in real time, including:
• Minimum and maximum peak detection
• Average number of measurement values since the last start-up
• Total number of start-ups
• Maximum span
By delivering processed results, such as peak values instead of raw data points, we simplify data analysis for the user and enhance the actionable insights our systems provide.
Sensor health monitoring
Finally, one of the most groundbreaking features of HBK smart sensors is their revolutionary health monitoring and diagnostic capabilities. Embedded health monitoring alerts users to overload conditions – critical in preventing sensor damage or failure during operation. It is this proactive approach to sensor maintenance that not only extends the lifespan of the equipment but also minimises downtime and maintenance costs, making it a valuable asset in any challenging industrial application.
FORTIFY YOUR MEASUREMENT FUTURE WITH HBK INTEGRATED AMPLIFIERS
When physical constraints permit, integrated amplifiers are the ideal choice for unlocking the full benefits of IO-Link, enabling maximum precision and reliability for your measurements. Integrated IO-Link amplifiers deliver simplicity, accuracy, and cost-efficiency unmatched by traditional methods. By combining sensing, signal processing, and communication into a single unit, these sensors remove the complex, manual setup and the inherent risks of human error associated with stand-alone configurations. At HBK, we have taken the lead in redefining measurement technology with advanced IO-Link solutions. Our unique approach integrates cutting-edge technology with deep expertise making us an industry leader in meeting the evolving needs of industrial applications. With our smart sensors, we help thousands of users achieve more accurate measurements, reduce maintenance and costs, and improve reliability in their operations.
