BML linear position encoder

Balluff’s new BML linear position encoder family provides direct measurement of a load’s linear position regardless of actuator backlash or mechanical wear. The BML sensing head floats above a precision-encoded magnetic band that provides an incremental position reference to the sensing electronics. This configuration provides up to 24 meters of non-contact, wear free position tracking up to 10m/s with no signal degradation over time. The non-contact BML comes in two models tailored to users’ accuracy requirements. The S1A model delivers maximum resolution of 1 µm and maximum system accuracy of ± 10 µm, while S1B offers maximum resolution of 5 µm and maximum system accuracy of ± 50 µm. Direct load measurement is more accurate and reliable than indirect rotary encoder-based positioning systems. Balluff’s BML accurately monitors linear load position independent of the specific actuator drive technology employed (ball screw, synchronous belt, rack and pinion, etc.). Direct load measurement also eliminates incorrect position information due to backlash in the linear drive system. This allows machine OEMs to choose less-expensive drive solutions without sacrificing position tracking accuracy. No need to use more costly “pre-load” or “zero backlash” actuators just to improve the accuracy of the rotary encoder at the motor shaft. Additionally, since the BML monitors the load position directly, the system is immune to catastrophic position errors caused by drive belt slippage or breakage that can affect motor shaft-mounted rotary encoders. Compared to many linear encoder alternatives, Balluff’s BML tolerates a wider operating gap without sacrificing accuracy. The S1A gap is up to 0.34 mm and the S1B gap is up to 2.0 mm. With typical linear encoders, too-small sensor gap specification can drive system costs up, because machine tolerances must be tight enough to meet the stringent gap requirements of the encoder. This wider gap can help lower machine costs by allowing manufacturing tolerances to be relaxed and by enabling the use of less expensive, lower precision linear slide components.