The Yokogawa EML 500-HS1 Master Unit (Type LT501) is the central processing component of the EML500 electromagnetic speed log system. While the sensor detects the ship’s speed through the water, the LT501 is responsible for powering that sensor, processing the raw signals, and distributing speed and distance data to bridge displays and other navigational equipment.

1. Core Functionality

The LT501 acts as the “bridge” between the underwater sensor and the ship’s navigation network:

• Power Supply: It provides a stable 24V DC power supply to the preamplifier built into the sensor.

• Signal Conversion: It receives a current signal from the sensor and converts it into speed and distance data using a high-reliability microprocessor.

• Data Distribution: It outputs information in multiple formats (Digital, Analog, and Pulse) to ensure compatibility with various bridge indicators, VDRs (Voyage Data Recorders), and ECDIS systems.