Main basis for selection of  pressure/differential pressure transmitter: 

1. Taking the index of the nature of the medium to be measured as the criterion, if the medium to be measured is used at the place with high viscosity and easy to be crystallized, the isolation-type transmitter must be selected. The corrosion of its medium to  metal of sylphon shall be considered, and the materials of sylphon must be well selected. The materials of sylphon of the sylphon are  ordinary stainless steel, 304 stainless steel, 316 L stainless steel and tantalum sylphon material, etc. 

2. During selection of the materials, the temperature of the medium to be measured shall be considered. If the temperature is high, it is generally is 200 ℃ ~ 400 ℃, the  high temperature type-materials must be selected, otherwise the silicone oil will produce vaporizing expansion, thus the measurement is not accurate. 

3. During selection of the materials, the working pressure level of the equipment must be considered, it must be consistent with the applications. From the selection of  measuring range of  transmitter, the common  transmitter has certain adjustable scope of range, it is better to set the measuring range to be used at 1/4 ~ 3/4 of its range, in this way the precision will be guaranteed, it is very important for differential pressure transmitter. 

4. According to the on-site installation location, the measurement scope and transfer volume are calculated, the migration has positive transfer and negative transfer.