Connected to a bubble probe, the BL is a level transmitter for liquids in open tanks. The BL consists of an open Ø16mm pipe at the bottom end and has two pneumatic connections at the top, one for the BL transmitter connection and one for the air inlet regulator to the BL. The pressure received by the transmitter is then converted to a 4-20mA or 0-10V analog signal, representing the liquid level in the tank. The transmitter is equipped with 2 independent relay points, which are regulated by means of the programming buttons.