Contrec 505 – LM01

Level Monitor

The 505 LM01 application monitors and measures the level of product in a single tank. The instrument uses the 4-20mA signal from a wide range of level sensors, including pressure transmitters, ultrasonic sensors and capacitance probes.

The level monitor provides a 20 point strapping table and product density for level to volume and volume to mass conversions. The instrument can display Volume, Percentage Full and Mass as well as Level. Relay alarms are freely assignable as high or low alarms and an open collector output is provided for programmable level control.

A sub-menu gives full details of alarm status and can offer direct access to change the alarm setpoints. The instrument also has density correction available for pressure level sensors to cater for a deviation in product density.


Calculations are based on the analog input signal representing the product level in the tank.

level = (Lmax – Lmin) x A + L min

volume = (Vmax – Vmin) ´ A* x V

min mass = volume x density


A = normalised input signal with density correction.

A* = A for linear tanks.

A* = f(A) for non-linear tanks.

f(A) = level to volume normalised strapping table.