AM-ULM-D Ultrasonic Level Differential Meter

AM-ULM-D carries two ultrasonic transducers, one above each of two measuring points, and each times the echo from its own surface. What it reports is the difference between the two levels: the level before and after a bar screen, or the fall from a channel to the basin it discharges into. Difference range is 0–25 m, accuracy ±0.5 %, with 4–20 mA, RS485 Modbus RTU and two relays; supply is 90–240 V AC or 12–24 V DC.

It is not a level meter with a second input. Buy it only when the number you need is a difference: on a single tank it reads one level twice, and you pay for two transducers and a difference channel. It is also blind where any ultrasonic is — foam, heavy vapour, a churning surface — and the table stops at atmospheric pressure, so a sealed or blanketed basin is out. No medium temperature is published either, so acid and hot service cannot be signed off.