Common faults and solutions of explosion-proof pressure sensors
Explosion-proof pressure sensor is an intelligent digital pressure sensor integrating pressure measurement, display, output and control. Its performance and characteristics are as follows:
The principle of explosion-proof pressure sensor is basically the same as that of ordinary pressure sensor. The pressure of the measured medium is transmitted to the explosion-proof transmitter through the connecting section. The measuring head is a component that can change the capacitance. Due to the action of the pressure, the capacitance of the measuring head changes with the change of the pressure.
The changing capacitance output by the measuring head is transmitted to the oscillator of the oscillation plate, and the oscillator changes the oscillation frequency according to the changing capacitance. The changed oscillation frequency signal is output by integrated operational amplification and detection to output a half-wave signal with a small oscillation frequency, and this signal is sent to Smart microprocessor.
Explosion-proof pressure sensor shell adopts isolation explosion-proof design, circuit according to explosion-proof design, circuit adopts signal isolation amplification, cut-off frequency interference design (anti-interference, anti-lightning) overvoltage protection, current limiting protection, impact resistance, corrosion resistance, compact and flexible, etc.316 stainless steel full seal welding, small and compact structure, good moisture resistance and excellent media compatibility.
In view of the common problems such as error, signal interference, and no signal that often occur in the use of explosion-proof pressure sensors, the following solutions are obtained through analysis and summary based on years of experience:
One: The pressure indication is unstable or incorrect
1. Whether the power supply of the explosion-proof pressure sensor is normal. If it is less than 12VDC, check whether there is a large load in the circuit. The input impedance of the pressure sensor load should meet RL≤(pressure sensor supply voltage -12V)/(0.02A)Ω.
2. The input impedance of the pressure sensor load should meet RL≤(pressure sensor supply voltage -12V)/(0.02A)Ω, if not, corresponding measures can be taken according to the difference: such as increasing the supply voltage (but it must be lower than 36VDC) ), reduce the load, etc.
3. Whether the input of the pressure indicating instrument and the corresponding wiring are correct, the input of the pressure indicating instrument is 4~20mA, then the output signal of the pressure sensor can be directly connected; if the input of the pressure indicating instrument is 0-10V, the pressure must be Instruct the meter to be tuned to the corresponding input.
4. Whether the range of the pressure indicating instrument is consistent with the range of the explosion-proof pressure sensor and connect a resistor with an accuracy of 1/1000 or more and a resistance value of 250Ω, and then connect to the input of the pressure sensor.
5. Check whether the input terminal of the multi-point paper recorder is open when there is no record. If it is open, then: 1. No other loads can be carried; 2. Use other recorders with input impedance ≤ 250Ω when there is no record.
6. Whether the corresponding equipment shell is grounded, the equipment shell is required to be grounded.
7. Whether the pressure sensor is damaged, severe overload sometimes damages the isolation diaphragm. If damaged, it must be returned to the manufacturer for repair.
8. Whether the temperature of the pipeline is too high, the general operating temperature of the pressure sensor is -25~85℃, but it is within -20~70℃ in actual use. If the temperature is high, a buffer tube can be added to dissipate heat.
Second:The pressure sensor has no output
1. Check whether the power supply of the explosion-proof pressure sensor is reversed;
2. Connect the ammeter in series with the 24V power circuit to check whether the current is normal;
3. If it is with a header, check whether the header is damaged. If the header is damaged, you need to replace the header.
