Compact strain gage instrumentation amplifier with IO-Link

Digitizing strain gage signals in the field at the sensor

Sensors with strain gages are used to measure forces or torques on shafts or components. Their design principle is that they use analog signals. For reliable transmission over longer distances in the field, the sensor experts at burster offer the robust IP65 plug & play model 9210 instrumentation amplifier in an aluminum housing. This digitizes the analog signals close to the sensor, and outputs them as an IO-Link protocol (see fig. 1). The high-precision amplifier electronics work with a non-linearity of < 0.005 % of full scale, and a 24-bit A/D converter ensures a maximum transmission rate at a measurement speed of 1000 values per second. As a result, the output voltage from the strain gages – which is typically only a few millivolts – is reliably amplified and transmitted over long distances, regardless of interference from electric motors, frequency converters, etc. in the field. To achieve this, the amplifier is connected to the master via the standardized IO-Link interface (M12). A single-shielded 4-core cable with an M8 plug is sufficient for the sensor connection. This makes wiring simpler and cheaper, as there is no need for complex analog shielding.

Practical bonus

Multi-channel measurement tasks often arise when using force, torque or pressure sensors because, for example, forces in different axes and additionally a torque have to be measured. In this case, several of the inexpensive instrumentation amplifiers can be connected to an IO-Link master without any complex wiring. Features such as peak value memory, a hold function, two digital switching points and filters further extend the range of applications, for example to monitor peak values. Flexible configuration via a standardized IO Device Description (IODD) file simplifies setup during installation or replacement.

Picture captions:

Figure 1: Robust and very precise: the new strain gage amplifier with protection class IP65 (source: burster)

Company box: About burster

burster supplies measuring technology ranging from individual sensors to system solutions. Its customers are mainly in mechanical and plant engineering, automation, the automotive industry and its suppliers, electrical and electronic engineering and the chemicals industry. The range includes measuring instruments and testers as well as standard sensors for mechanical and electrical measured values, such as load cells, pressure, torque and displacement sensors, milli- and megohmmeters, and resistance decade boxes. In addition, individual custom OEM solutions are possible, including for many other sectors and future markets such as medical engineering, biotechnology and e-mobility. Many years of experience in designing and building measuring instruments and sensors guarantee optimum solutions every time. Developed and manufactured in Germany, burster sensors, amplifiers and transmitter modules, precision instruments and measuring systems for sensor signal processing are shipped to customers all around the world.