Mass flow and volume flow SMV3000 / 100 series full of smart multivariable transmitter applications 1. The need for temperature and pressure compensation of the ideal gas measurement 2. the need for mass flow and volume flow temperature and pressure of the fluid dynamic compensation measure 3 mass flow density compensation required of superheated vapor and volume flow measurement wire classification: two-wire system: thermal resistance at both ends of each wire connected to a lead-wire resistance signal is called: This method is very simple lead But there must be due to the connection wire lead resistance r, r size and length of the wire material factors relating to, so this method is applicable only lead to less accurate measurement occasions; three-wire system: thermal resistance of the base at one end of a connection Lead the other end of the two leads is called three-wire Rosemount differential pressure transmitter, this approach is usually associated with the bridge supporting the use of lead resistance can be better to eliminate the impact of differential pressure transmitters, industrial The most commonly used process control; and four-wire system: the root ends of the thermal resistance of the connecting two wires is called four-wire system, which the two leads provide a constant current I is thermal resistance, the R into a voltage signal U differential pressure transmitter, and then through the other two leads to U lead to the second instrument. This approach can be seen completely eliminate lead wire resistance influence differential pressure transmitter STD720, mainly for high-precision temperature detection. RTD three-wire connection. Three-wire connection to eliminate measurement errors caused by lead resistance. This is because the measurement of thermal resistance of the circuit is generally unbalanced bridge. Thermal resistance as a bridge arm resistance of the bridge, connecting wires (from the thermal resistance to the control room) has become part of the bridge arm resistance, and this resistance is unknown and part with the ambient temperature changes, resulting in a measurement error. Three-wire, the wire connected to a power supply terminal of the bridge, the other two are respectively connected to the thermal resistance of the bridge where the arm and the adjacent bridge arm, which eliminates measurement errors caused by lead wire resistance. Differential pressure transmitter, differential pressure transmitter, Hua Hui science and technology provided by the Jinan-Technology Co., Ltd. Jinan Huahui Technology Co., Ltd. (www.cnhuahui.com/) strong, credible, in Jinan, Shandong pressure instrumentation industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead China-Technology into the brilliant and you work for a better future!