Motor feedback system SKS36 adjusts precise positioning
Ortlieb applies the SICKStegmann motor feedback system SKS36 with HIPERFACE® interface to all SERAC® product lines. “The compact design ensures a short motor mounting length” and NielsSelig cites an important structural advantage. In fact, the well-designed system structure allows the housing to be only 36 mm in diameter, while the height of the structure (without the shaft) is also extremely small, only 37 mm. For this reason, the motor feedback system is only “heavy” 65g, making it one of the most compact encoders in its class. As a single-turn encoder system in the Ortlieb servo electric cylinder digital adjustment circuit, the SKS36 provides values for steering, speed and absolute position information by subdividing into a single-turn rotation of 128 sine/cosine cycles. At the same time, the system is extremely reliable and accurate – this is achieved mainly by a very small code wheel, which is located in the middle of the axis of rotation, thus eliminating any eccentricity errors. The code wheel has 128 lines, and the specially developed Opto ASIC scans it to produce a sinusoidal signal with extremely high linearity and interpolation feasibility. “This makes it possible to measure the feed of the SERAC screw with great precision and for precise positioning,” explains NielsSelig. Only because the working mode of the planetary roller screw is not a form fit, but a rolling friction fit. “There can be significantly more force, and the life of the screw is not affected,” says Niels Selig. “The working principle causes the screw to slip when it is running, so an additional linear measuring system is required in addition to the encoder. In this way, the positioning accuracy of <0.01mm and ±0.01 can be achieved by the mutual cooperation of the two encoder systems. The repeatability of mm." SKS36 is also distinguished by its high precision, high availability and robustness. “The maximum operating temperature allowed in the servo cylinder is much lower than the 125 °C specified by the encoder,” Niels Selig describes. “Vibration and shock that may occur during stamping, forming and pressing will not impair the functional reliability of the SKS 36. For example, the SERAC® KH electric cylinder equipped with this motor feedback system can complete more than 4 in a three-second sync signal during sheet metal forming. Millions of cycles without any problems."
Multi-turn and safety solutions for mechatronic systems
In the Ortlieb electric cylinder, the single-turn motor feedback system SKS36 is convincing due to its precision, convenient integration and availability. For mission settings that require repeated rotational displacement measurement and positioning, the multi-turn motor feedback system SKM36 measures up to 4,096 rotations with a built-in micromechanical transmission and outputs up to 16,777,219 steps.
SICKSTEGMANN's SIL2 motor feedback systems SKS36S and SKM36S stand out as safety encoders in dynamic precision servo control circuits for safety-oriented mechatronic systems and drive technology solutions. These two systems can be used for applications that comply with the SIL2 classification according to EN62061 and IEC61508 and the performance level (PLd) according to ENISO13849-1. As a result, they offer certified functional safety, which enables safety-oriented monitoring of the speed, steering and shutdown of the functions and function chains of servo electric cylinders and mechatronic systems. The SICKStegmann motor feedback system provides a wide range of displacement measurement and positioning options in mechatronic systems – not just in Ortlieb's electric cylinders.
