Wire classification: two-wire system: thermal resistance at both ends of each wire connected to a lead-wire resistance signal is called: This wiring method is very simple, but there must be connected to the wire lead resistance r, r size and wire Factors related to the material and length, so this only applies to lead the way lower precision measurement occasions; three-wire: Connect one end of the heat resistance of the lead in the roots, and the other end connected to the two leads is called three-wire Original MCT404, this approach usually associated with supporting the use of the bridge, it can better eliminate lead resistance effect MCT404, industrial process control of the most common; four-wire system: the root ends of the thermal resistance of the connecting two wires The approach is called a four-wire system, which the two leads provide a constant current I is thermal resistance, the R into a voltage signal U, and then through the other two leads to U lead to the second instrument. Seen this way can lead to completely eliminate lead resistance effect, mainly for high-precision temperature testing. 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 HART MCT404, the wires 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, thus eliminating lead resistance line brings measurement error. SMEs as an open distributed control system to maintain the best performance of the system at the same low cost. PlantScape Vista / HC900 to meet the application requirements of various devices of process automation control dual-protocol MCT404 Communicator, is flexible, reliable sized distributed control system, it is currently used as a substitute for all PLC programmable logic controller on the market the ideal solution for every device process control systems. 1. Open system architecture 2. Flexible and reliable integrated controller 3. The spot color LCD operator interface 4. Easy to use and fully functional system configuration tool imports MCT404_ Honeywell (certified) _MCT404 provided by the Jinan-Technology Co., Ltd. Jinan Huahui Technology Co., Ltd. (www.cnhuahui.com/) Shandong Jinan, pressure meters leaders, over the years, the company implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. - Technology leader in China with the staff warmly welcome all inquiries negotiations to create Hua Hui Technology better future.