kubler articles

When Things Get Tough

Kubler 4/1/2016

When Things Get ToughAdvantages such as a new magnet technology make the encoders of Kubler's Sendix M36 series very attractive for all kinds of construction machines. This is also reflected in an extremely robust variant for toughest applications. 
Freely adapted from Anna Karenina, all factors must be met for the success of an undertaking. This is particularly visible especially in technical components. The users must be sure they can rely on them, and this is the challenge for the manufacturers. In the multiturn encoder technology area, the sensors manufacturer Kubler meets this challenge with three different variants. Besides two optical methods, the company now presents the magnetic 
Harvesting Technology, which is based on Hall sensors and allows a revolutions count without battery and without gears. So the required energy is produced directly by the rotating magnetic field. According to the manufacturer, components equipped this way are first of all compact and robust and moreover branch and application-optimized. He wants this way to set up a wide multiturn portfolio able to meet any requirement.

Mobile automation has been the promoter of the Energy Harvesting Technology, as the advantages of this method are best visible in cranes or mobile construction and working machinery. Even though this solution has been used for many years for absolute position acquisition in singleturn encoders, there still was no possibility to count several revolutions without external power supply.

With Kubler's Energy Harvesting, the user can now dispense both with a gear and with a buffer battery. This is expressed in the new magnetic encoder Sendix M36, which generates itself the energy it needs for the multiturn sensor signal and for the counting and saving of the measurement signals. When it is not powered, the new component counts the revolutions autonomously, gaining the energy it needs directly from the movement of the drive. Also the very robust housing of the new magnetic encoders of the Sendix M36 series contributes to meet all requirements of extreme applications such as in mobile cranes or construction machinery. Their total insensitiveness to dust and condensates allows using them even in unprotected systems in such harsh environments.

According to Kubler, even though the priceperformance ratio is attractive, the really important point is that this progress benefits the work and process safety in mobile machines. As all Sendix appliances, the M36 series is equipped with Safety-Lock, the magnetic version even with Safety-Lock plus. Here, the shaft seal has an additional mechanical protection. This allows high protection levels such as IP67 or IP69K. With a size of 36 millimeters, the new magnetic encoders are extremely compact. They are available both with analog outputs and with an SSI and CANopen interface. The solid shaft versions are mounted using a coupling, while the hollow-shaft encoders are mounted directly on the motor shaft.

The extremely robust variant Sendix M36xxR, intended for demanding outdoor applications, ensures even more robustness and safety. It includes a stainless steel housing and offers higher bearing loads. These encoders are tested extensively, for example in compliance with a special standard for "road vehicles". Particular focus is set on environmental requirements such as the combination of temperature, humidity and dust.

Extremely robust, extremely reliable

Kubler provides the Robust variants with a flange diameter of 42 and 58 millimeters and as a shaft variant. Thanks to the robust bearing structure in Safety-Lock-plus design, they withstand shocks, vibrations and installation errors. Extra large bearings ensure high bearing load capacity, and therefore high reliability and plant availability. Its magnetic scanning makes this device insensitive to dust and condensation, and the wide temperature range from -40 to +85 degrees Celsius ensures high resistance. The total resolution reaching 38 bits results from the combination of a multiturn encoder with a maximum of 24 bits and of a highly accurate singleturn stage with up to 14 bits, making this encoder very versatile.

This appliance is used as a standard in mobile automation with a CANopen or SSI interface and with various analog outputs. Nevertheless, Kubler goes on relying on its optical methods, as these are the most usual method in all branches for applications requiring highly accurate measurements. Optical encoders use rotating coding disks with special patterns to generate measuring data. These disks let light reach photoreceptors at periodic intervals, generating light patterns on the sensor plate to indicate the current angle. Multiturn encoders do not simply measure the current axis angle, but they also monitor the number of revolutions. Optical encoders based on the gear technology are fast and highly accurate. As they operate without any magnetic sensor, they are moreover insensitive to strong magnetic fields and operate without battery - which makes them the first choice for the feedback of geared motors. This is true also for hard-to-reach locations such as wind power plants or harbor cranes.

Encoders with Intelligent Scan Technology (IST) are gearless and compact. The patented chip-based technology ensures even higher resolutions and more accurate measurement results. An output of up to 16,777,216 unequivocal revolutions is an argument for their use in highly-integrated and therefore dynamic feedback systems for servomotors. The gearless operation ensures the robustness and insensitiveness of the optical IST encoders. They are used wherever travels are relatively long, that is to say for high-bay warehouses, crane construction or machine tools. They can also readily be integrated in drives or in robots.