The Heidenhain 689683-21 from the LC 485 series is an exposed absolute linear encoder designed for high-accuracy position measurement in numerically controlled machine tools, coordinate measuring machines (CMMs), and precision automation applications where space is limited. Featuring a 570mm measuring length (ML 570) with a slimline scale housing, it provides absolute position feedback across the full stroke without requiring homing cycles, using a 40µm grating period and advanced photoelectric scanning for ±5µm system accuracy and 5nm (0.000005mm) resolution. The encoder supports traverse speeds up to 240 m/min and accelerations of 50 m/s², making it suitable for dynamic linear axes in 5-axis machining centers.
Equipped with the EnDat 2.2 bidirectional serial interface for absolute data transmission plus absolute incremental signals (~1 Vss/1 Vpp), it enables fast position acquisition, extensive diagnostics, and PLC integration. The aluminum slim housing (20mm height) with pneumatic sealing ensures IP67 protection against coolant, swarf, and contamination, while secure mounting via adhesive tape or screws maintains signal stability under vibration loads up to 100 m/s². Operating on 3.6-14V DC with low power consumption (<200mA), it delivers MTBF >70,000 hours and signal lifetime >10^9 edges, with comprehensive error compensation for thermal expansion, aging, and contamination—ideal for 24/7 production environments requiring sub-micron repeatability.
