Brief Introduction and Analysis of Knowledge about Gas Detection Instruments
Brief Introduction and Analysis of Knowledge about Gas Detection Instruments
Standard gas is a gas whose composition, concentration, and precision are all known.
Explosive environment and explosion-proof electrical equipment: An environment containing an explosive mixture is called an explosive environment. Electrical equipment that is designed and manufactured according to specified conditions and will not cause the explosion of the surrounding explosive mixture is called explosion-proof electrical equipment for explosive environments.
Explosion-proof marking: The state has clear regulations on various explosion-proof types of explosion-proof electrical equipment for explosive environments. In "dIICT6", "d" indicates that the explosion-proof type is the flameproof type, "II" indicates electrical equipment for factory use, "C" indicates the strictest level of the maximum experimental safe gap or the minimum ignition current ratio (Level A, B, C) of the explosive gas mixture, and "T6" indicates the strictest level of the allowable maximum surface temperature (85°C).
Bus and branch line: Bus and branch line refer to the connection methods between the controller and the detector. If each detector requires a wire to complete the communication with the controller, this connection method is called a branch line connection. If several detectors can share a wire to complete the communication with the controller, this connection method is called a bus connection.
Binary system: In a bus system, the coding of devices on the bus adopts the binary system. 8 represents the high bit, 1 represents the low bit. When it is toggled to the ON side, it is 0, and when it is toggled to the OFF side, it is 1. The coding formula is as follows: Coding number = 1×N1 + 2×N2 + 4×N3 + 8×N4 + 16×N5
Sensor preheating: After the sensor is powered on, the output value is unstable. The period of time waiting for the output value to stabilize is called sensor preheating.
Sensor poisoning: When the sensor is in the powered-on state, if it comes into contact with a gas whose concentration is far beyond its measurement range, it is possible that the output value of the sensor will always remain at a high level. Some poisoned sensors can be restored after a period of time, while some cannot be restored.
