The LST400 is an ultrasonic level and open channel flow transmitter for liquid and solid measurement up to 15 m. It has a wall- or pipe-mount polycarbonate housing, IP65/NEMA 4X protection, and dimensions of 230 x 94 x 192 mm. It includes a 4 to 20 mA HART 7 output, five 8 A relays, and a graphic display. Powered by 110/220 V AC or 20-30 V DC, it operates from -20 to 65 °C and meets EN61326-3 and IEC 61010-1 standards. Standard transducers (S15, F15, C15) support ranges up to 15 m with 41 kHz frequency; the S30 model covers 1.5 to 30 m at 15 kHz. Automatic gain and pulse adjustments, a 21-point linearizer, and pump cycling are integrated.
The transmitter’s microprocessor simultaneously fires an electronic pulse to the transducer and starts a timer. The transducer converts this electronic pulse to an acoustic pulse, which is directed toward the surface of the material being measured. When the acoustic pulse contacts the surface of the material, energy is reflected back to the transducer, which converts this reflected energy back to an electronic pulse. This pulse is sent back to the microprocessor, which stops the timer and determines the “time of flight” of the signal. By combining the speed of sound through air and the “time of flight” of the pulse, the microprocessor accurately determines the level of the product. Powerful software removes false echoes from the signal and electronic filters remove ambient noise.
| ABB Measurement & Analytics | |
|---|---|
| Product Category | Level Sensors |
| Product Number | LST400 |
| Product Name | Ultrasonic Level Transmitter |
| Device Classification | Transmitter |
| Media Type | Liquid |
| Level Measurement Type | Single Point or Multi-Point Level |
| Meter Technology Type | Ultrasonic/Sonic |
