1 Working principle
The CNPS-MHP type is a dry ceramic piezoresistive sensor imported from Germany using ceramic materials and refined by special techniques. Ceramic is a recognized material that is highly elastic, corrosion resistant, abrasion resistant, impact resistant and vibration resistant. The thermal stability of the ceramic and its thick film resistance can be as high as -40 ° C ~ +120 ° C, and it has high precision and high stability. The degree of electrical insulation is >2kv, the output signal is strong, and the long-term stability is good. There is a tendency to completely replace other types of sensors in European and American countries.
The output of the sensor adopts the 4-20 mA two-wire industrial standard. The outer casing is made of corrosion-resistant stainless steel and German Hirschmann joints. The protection grade can reach 1P65. In addition to oil fields, it is widely used in industrial control, mining, food processing, automobiles, Many industries such as electronics and medical care.
2 Technical indicators
Power supply voltage: 15~36VDC,
Signal output: 4-20mA,two-wire system
Linearity to hysteresis: ≤0.3%FS (25℃)
Measurement range: 0-2.5bar
Stability: ±0.5% FSO/year
Operating temperature range: -40~+85℃
Temperature effect: ≤±0.015%FS/℃
Electrical line protection: polarity protection, over current protection
3 Installation and use
The sensor can be mounted directly on a suitable threaded interface. The mounting position has no effect on the measurement. In order to meet the CE standard, a shielded cable must be used. The shield of the cable must be connected to the casing and the ground.Do not pull or pull the lead of the sensor when using it. Do not use the lead to pull the sensor. The aviation plug should not be immersed in water. Wrap the waterproof object around the connector.
4 Fault judgment:
If there is no signal output or output value during the pressure sensor drilling process, first check if the extension cable is open or accessible. When the pressure reading is not correct, first check if the sensor is missing hydraulic oil or if there is air bubbles in the oil circuit. If there is no oil, use the manual pump to refuel, and if there are bubbles, the bubbles will be drained.
If the pressure sensor is suspected to be faulty, the sensor and piston pressure gauge can be disconnected. According to the engineering range of the sensor, when the input voltage is zero and full scale, the signal current should be about 4 and 20 mA respectively, otherwise the sensor is faulty and sent back to the company. service.
There are two potentiometers in the sensor to adjust the sensor output zero and full scale values. You can see the Hirschmann connector and the sensor back cover. The 504# is zero point adjustment and the other potentiometer is full scale adjustment. Through current and standard pressure source, adjust the 504# potentiometer when the pressure is zero, the sensor output is 4mA, then adjust the pressure source to the full-scale pressure, adjust the other potentiometer, so that the sensor output 20mA, so repeat the adjustment Three times.
For oilfield users, the general demand is: 1.6Mpa, 6Mpa, 20Mpa, 40Mpa. Available for any other range from 0 to 50 MPa.