How it is selected & specified.
The two-wire ultrasonic level transmitter is selected when the buyer wants a simple continuous 4-20 mA signal from an ultrasonic sensor. It is common in water treatment, process water, wastewater sumps and compatible chemical day tanks.
Compared with a split controller, a two-wire transmitter is cleaner for PLC input. Compared with an integrated relay type, it is less suitable when local pump logic or multiple relay points are required.
The transmitter still follows all ultrasonic installation rules. Blind zone, nozzle height, foam, vapor, turbulence, filling stream and tank internals must be checked so the loop signal represents a stable echo.
When the site needs HART, RS-485, local display or relay alarm, WELK will confirm whether those functions are available in the selected two-wire family or whether another ultrasonic variant is better.
