Electronics with flair: Sensors for construction machinery

Machines do not feel like we do; they use sensors to measure their status and environmental parameters. What works reliably and repeatably in a controlled laboratory environment can be tricky in the harsh reality of construction sites. GEMAC Chemnitz has over 30 years of experience in sensor technology and produces systems that master the balancing act between the desired sensitivity to measuring stimuli and the required robustness against environmental influences. We spoke to Managing Director Tilo Rothkirch about the crucial details in sensor technology and fieldbus diagnostics, the company's two main business areas.

"We have 30 years of experience in these areas. At GEMAC, development and production occur entirely in Germany, with 71 employees at the Chemnitz site. We sell our products worldwide via a selected dealer network." Tilo Rothkirch, Managing Director GEMAC

What is GEMAC's specialty?

Tilo Rothkirch: On the product side, we serve two main business areas: Firstly, sensor technology with inclination sensors and inertial measurement technology, and secondly, fieldbus diagnostics with products for physical fieldbus diagnostics for CAN-based networks. A third business area is EMS services, i.e., PCB assembly for selected customers. We have 30 years of experience in these areas. Development and production at GEMAC are carried out entirely in Germany, with 71 employees at the Chemnitz site. We distribute our products worldwide via a selected distributor network. Our target group is manufacturers of mobile machinery. Gemac products are used in construction machinery, in forestry and agriculture, in crane and lifting technology and in ships.

GEMAC was one of the first suppliers of dynamic inclination sensors and has built up a lot of know-how in this field. We use our knowledge of the application and the physics of the sensor for sensor fusion and do not just sell a 'dumb' sensor with a Kalman filter as a purely mathematical model. Instead, we use a sensor fusion algorithm developed in-house that outperforms classic filters, such as complementary or Kalman filters, in terms of accuracy and performance. We also prioritize performance and customer benefit in the field of fieldbus diagnostics. The aim is the simple, comparable evaluation of all physical bus parameters. We use the same software on the device and the PC. So there is no need to get used to it; the tool can be used both mobile and stationary. Our Fieldbus diagnostics device works with a remote measuring head and has short measuring cables to prevent interference with the bus signal.

Sensorfamilie GEMAC MOTUS

The configurable GEMAC MOTUS sensor measuring unit enables 6-axis motion detection on mobile power machines. Three product lines with three different performance classes offer the right solution for every application.

What products does GEMAC develop and manufacture for the construction sector?

Tilo Rothkirch: Our entire GEMAC MOTUS sensor range can be used in the construction sector. Different variants cover different customer-specific requirements. GEMAC MOTUS is the premium version, installed in a die-cast zinc housing. The sensor with 6-axis motion detection achieves an extremely high accuracy of up to ±0.1° (static) and ±0.25° (dynamic). The special feature here is the sensor fusion algorithm developed by GEMAC with the 'Enhanced Kalman Filter', which is specially optimized for motion detection and performs the high-precision orientation calculation. The GEMAC MOTUS is available in three basic types with different technical specifications: Firstly, the XB/XC as an inertial measurement unit (IMU) with a recording of static/dynamic inclination, acceleration and rotation rate, then the IB version as an inertial measurement unit (IMU) with a recording of acceleration and rotation rate and thirdly the NB/NC variant as a dynamic inclination sensor.

The GEMAC MOTUS Blackline is the basic version in a plastic housing. The highest accuracy is up to ±0.1° (static) and up to ±0.5° (dynamic). The Blackline also works with GEMAC's own 'Enhanced Kalman Filter'. We offer the sensor in three basic types: XB/XC as an inertial measurement unit (IMU) recording static/dynamic inclination, acceleration and rotation rate, NB/NC as a dynamic inclination sensor and SB/SC as a static inclination sensor.

We call GEMAC MOTUS Greenline the cost-benefit-oriented variable compact version in a plastic housing. There are two standard housing variants for 2- or 4-point mounting. The accuracy is ±0.1° to ±0.5° (static) and up to ±0.8° (dynamic). We also offer the Greenline in three basic types: XE as an inertial measurement unit (IMU) recording static/dynamic inclination, acceleration, and rotation rate, NE as a dynamic inclination sensor, and SE as a static inclination sensor.

In addition to the sensors, our fieldbus diagnostic devices can be used in the construction sector, as the CAN bus is used in many machines. Many of the PCBs we assemble are also used in construction machinery.

What are the special requirements for sensors used in construction machinery?

Tilo Rothkirch: There are many external influences, such as movement, unevenness, soiling, vibrations, impacts, jerky rotations, temperature fluctuations, etc. GEMAC MOTUS, as a power IMU, is a robust and precise measuring instrument that has fulfilled the required measuring tasks with maximum reliability for many years, even under these demanding and harsh conditions. With the GEMAC MOTUS, our self-developed algorithm enables highly accurate orientation calculation and corrects non-linear disturbance variables, supported by sensor fusion filters that suppress externally acting accelerations. The sensors, therefore, deliver even more reliable values for highly dynamic applications and the permanent movement of a mobile machine. In addition, our sensors have robust housings made of die-cast zinc or plastic, depending on the product line, which are encapsulated with polyurethane.

What advantages does the GEMAC MOTUS series offer construction machinery manufacturers?

Tilo Rothkirch: The sensors feature automatic configuration of the mounting position and flexible zero-point adjustment. All product lines are available for five interfaces: for the analog interfaces current and voltage and for the digital interfaces CAN, CANopen and SAE J1939. GEMAC MOTUS Blackline and GEMAC MOTUS Greenline are also available in different colors for customer-specific projects.

Another significant advantage is that by combining and calculating all measured values directly in the measuring unit, only one measuring system needs to be integrated into the mobile application for a wide range of requirements. The sensor measuring units, which can be easily parameterized via a programming kit, allow users to optimally adapt their applications with the sensors to the existing technical requirements.

GEMAC advertises with "Made in Germany". What are the customer benefits of domestic development and production?

Tilo Rothkirch: GEMAC has been developing all products in sensors and fieldbus diagnostic devices in-house for over 30 years. Each sensor is calibrated at the factory and is available with a certificate of accuracy on request. The products can be pre-configured according to the customer's specific application. Extensive initial consultation to find the right product for the customer is a matter of course for us. We also offer support with sampling at the customer's premises. The quality of our support is therefore very high. We also assist with the implementation of the sensors if required.

In the field of fieldbus diagnostics, we offer a unique physical measuring device with direct qualification of the signal quality. Intuitive operation is the same as with tablets and smartphones. The quality of support is also very high here. We assist with the use of Fieldbus diagnostic devices, support troubleshooting, and also offer general advice on the possibilities in CAN systems.

Presentation of the CAN Bus Tester GT3 at AGRITECHNICA 2023

The highlight at Agritechnica 2023 was the newly presented CAN Bus Tester GT3 with an extra robust 10" touch display.

Managing Director Tilo Rothkirch at AGRITECHNICA 2023

"With the GEMAC Academy, we have set up our online training portal. We also offer face-to-face training either at our premises or directly at the customer's premises." Tilo Rothkirch, Managing Director GEMAC

What are GEMAC's new plans?

Tilo Rothkirch: We are currently working intensively on further innovations and improvements, particularly in the field of fieldbus diagnostics. The integration of an OBD-II analysis for the functional level is planned as an extension of the GT3's scope of services. The aim is to offer a complex overall solution for fieldbus diagnostics for mobile power machines that combines the physical, digital and functional levels in one diagnostic solution. The WiFi connection of the tester and measurement methods for determining the CAN bit timing of a subscriber is also being planned.

What are customers struggling with in sensor/bus systems, and how can you help?

Tilo Rothkirch: A typical problem is that the customer himself is not aware of the interferences that occur in his application. In these cases, the experience of GEMAC engineers in algorithm development comes in handy. Findings from data analysis at other customers often also help. We are also regularly confronted with the fact that a participant is added to the CAN bus, which is then held responsible for a subsequent bus failure. Sometimes, however, this is not the actual cause but the straw that breaks the camel's back. GEMAC Chemnitz helps here with its field bus diagnostic tools to assess the situation and find the exact cause of the fault.

You have introduced the CAN bus tester GT3. What features does the device offer?

Tilo Rothkirch: The GT3 has robust outdoor housing with a VESA mount. It has a high-resolution 10" rugged touch display as the ideal basis for harsh working environments. The great advantage of the GT3 is the combination of physical measurement and protocol analysis, both in CAN-FD and classic CAN. Its areas of application are development, final acceptance, service and troubleshooting. The device works with a remote measuring unit for direct connection to the CAN bus without signal-distorting stub lines and enables measurements even in hard-to-reach places. Its high-resolution 12-bit 2-channel oscilloscope offers comprehensive decoding and adjustable time and voltage ranges. The GT3 software can be adapted to the protocol used by the application using a license key. Physical measurement is possible in all CAN and CAN FD-based protocols. On the protocol side, we support symbolic decoding, CANopen, DeviceNet and SAE J1939 with the ISOBUS and NMEA2000 extensions.

The measurement system will offer an extension to include a database solution for various machine documents such as circuit diagrams, maintenance intervals, data sheets, etc. At the physical level, even more comprehensive measurements in the CAN bus are possible, including evaluations of the signal quality in CAN FD and bit timing measurements. The combination of dual-channel oscilloscope with decoding and automatic signal quality determination makes the GT3 a powerful tool for troubleshooting, signal analysis, protocol monitoring and developing CAN-based circuits and systems.