Xi'an Huafan Technology Co.,LTD is a professional gas detector factory since year 2003,manufacture many styles gas detectors include portable and fixed style,detect many gas,such as CO O2 H2 CO2 H2S NH3 SO2 NO HF C2H4 etc. For fixed gas detectors,we have 3types signal output.
1. 4-20mA signal output
The 4-20mA gas detection transmitter is an instrument produced by our company that can continuously detect the concentration of toxic, harmful, flammable and explosive gases in the working environment. The detector detects gas concentration by natural diffusion and uses imported sensors with good sensitivity and excellent repeatability. The instrument uses embedded micro-control technology and has high reliability. Used in conjunction with the gas branch line control cabinet produced by our company, one control cabinet can be connected to multiple branch line probes. The output mode is two-wire or three-wire. The three-wire gas transmitter can output a set of relay switching signals. The transmission distance limit is 1000 meters. The two-wire gas transmitter uses a two-core shielded cable with a cross-section of 2×1.5mm2. The three-wire gas transmitter uses a three-core shielded cable of 3×1.5mm2 (the shielded wire can prevent on-site The dry resistance of other signals), the power supply of the gas probe in this connection mode is provided by the gas control cabinet (24V DC).
2. Bus 485 digital signal output
The 485 series bus-type gas detection and alarm system uses non-standard protocol or MODBUS protocol for data collection and transmission. The intelligent transmitter node collects and detects the gas concentration on site. The host patrols and detects each node. With the intelligent background software, real-time Monitor on-site gas concentration changes. It adopts a bus mechanism, has strong anti-interference ability, convenient layout and simple wiring. At the same time, the intelligent transmitter node also provides a switching output that can control external equipment (exhaust fan, solenoid valve, etc.). Used in conjunction with the gas bus control cabinet produced by the company, one control cabinet can connect multiple bus probes, and the output mode is a four-wire system (two power lines, two signal lines). Use two two-core shielded cables or one four-core shielded cable with a cross-section of 2×1.5mm2×2 or 4×1.5mm2.
3. Two bus Power Bus
Power Bus collects data in the form of a bus. Compared with RS-485 bus and 4-20mA branch line, it is more complete. It inherits the advantages of RS-485 bus and 4-20mA branch line and eliminates their defect. It consists of a master device, several slave devices and a pair of connecting cables. All slave devices are connected to the bus in parallel, and the master device controls all serial communication processes on the bus.
Power Bus uses power lines as data transmission lines, modulates power for data communication, and uses power lines and data lines together to reduce wiring difficulty and wire usage. It is connected to the two-bus control cabinet produced by the company through a bus. There are many topological connection methods such as star, tree, bus, etc.