Siemens Sitrans LR200 Instruction Manual page 186

stilling-well: see stillpipe.
two wire radar: a low-energy radar. Can be loop powered, analog, intrinsically safe 4 to 20 mA,
or a digital (BUS) transmitter.
TVT (Time Varying Threshold): a time-varying curve that determines the threshold level above
which echoes are determined to be valid.
waveguide antenna: a hollow, metallic tube that transmits a microwave signal to the product
target.
Page 178 SITRANS LR200 (HART) – INSTRUCTION MANUAL 7ML19985JP02