The sensor contains a weight [A] suspended by a cable [B] with motion provided by a motor drive [C] and associated electronics.
The measurement cycle is initiated either on demand or on a timed interval and causes the sensor to lower the weight to the material level. As the weight is being lowered, the length of cable dispensed is measured in 0.1 ft (0.03 m) increments.
When the weight reaches the material level, the unit reverses and the weight is drawn into the stored position in the sensor. The distance measurement can then be transmitted via 4-20mA, voltage pulses, or RS-485 MODBUS.