Item No: SHLD-RD model parameters prior to contact customer service renovation and construction content: the installation of a measuring principle is based on the time travel guided wave radar principle of measuring instruments, radar speed of light, running time can be converted into purified by electronic components signal. Probes emit high-frequency pulse and propagates along the cable or rod probe type, reflective surface material when they hit back by the receiver in the instrument cluster, and converted to a signal from the signal level. The reflected pulse signal along the cable or rod probe type conduction to the instrument electronics section, microprocessor processes this signal, identify the microwave pulse echo generated in the material surface. Correct echo signal recognition by the pulse software to complete the distance D from the material surface and the pulse travel time T is proportional to: D = C × T / 2 where C is the speed of light due to the known empty distance E, the level L to: L = ED by entering the empty height of E (= zero), full tank height F (= span) and some applications to set the parameters, application parameters so that the instrument will automatically adjust to the measurement environment. Corresponding to 4-20mA output.