5: Check whether the power cord is connected correctly Solution: The power cord should be connected to the corresponding terminal
1: Whether the transmitter power supply is normal Solution: If it is less than 12VDC, check whether there is a large load in the loop, and the input impedance of the transmitter load should meet RL≤(transmitter power supply voltage -12V)/( 0.02A ) Ω
2: Whether the actual pressure exceeds the selected range of the pressure transmitter; Solution: Re-select a pressure transmitter with an appropriate range. Whether the pressure sensor is damaged, severe overload sometimes damages the isolation diaphragm. Solution: It needs to be sent back to the manufacturer for repair.
4. Wrong indication of FKG pressure indication
1: Whether the transmitter power supply is normal Solution: If it is less than 12VDC, check whether there is a large load in the loop, and the input impedance of the transmitter load should meet RL≤(transmitter power supply voltage -12V)/( 0.02A ) Ω
2: Whether the referenced pressure value must be correct Solution: If the accuracy of the referenced pressure gauge is low, another pressure gauge with higher accuracy needs to be replaced.
3: Whether the range of the pressure indicating instrument is consistent with the range of the pressure transmitter Solution: The range of the pressure indicating instrument must be consistent with the range of the pressure transmitter
4: Whether the input of the pressure indicating instrument and the corresponding wiring are correct Solution: If the input of the pressure indicating instrument is 4~20mA, the output signal of the transmitter can be directly connected; if the input of the pressure indicating instrument is 1~5V, then A resistor with an accuracy of 1/1000 or more and a resistance value of 250Ω must be connected to the input end of the pressure indicating instrument, and then connected to the input of the transmitter.
5: The input impedance of the transmitter load should meet RL≤(transmitter supply voltage -12V)/(0.02A) Ω
Solution: If it does not meet the requirements, corresponding measures can be taken according to the difference: such as increasing the supply voltage (but it must be lower than 36VDC), reducing the load, etc.
6: Check whether the input terminal of the multi-point paper recorder is open when there is no record; Solution: If it is open, then: a. No other loads can be carried; b. Use other recorders with input impedance ≤ 250Ω when there is no record.
7: Whether the corresponding equipment shell is grounded Solution: The equipment shell is grounded
8: Is it separate from the AC power supply and other power supplies? Solution: Separate the wiring from the AC power supply and other power supplies
9: Whether the pressure sensor is damaged, severe overload sometimes damages the isolation diaphragm. Solution: It needs to be sent back to the manufacturer for repair.
10: Whether there are sand, impurities, etc. in the pipeline that block the pipeline, and the measurement accuracy will be affected when there are impurities; Solution: Clean the impurities and add a filter before the pressure interface.
11: Whether the temperature of the pipeline is too high, the operating temperature of the pressure sensor is -25~85℃, but it is best to be within -20~70℃ in actual use. Solution: Add a buffer tube to dissipate heat. It is best to add some cold water to the buffer tube before use to prevent the superheated steam from directly impacting the sensor, thereby damaging the sensor or reducing its service life.
The common faults of Fuji FKG transmitter are:
1. When the pressure goes up, the pressure transmitter can't go up: In this case, first check whether the pressure interface is leaking or blocked. If it is confirmed that it is not, check the wiring method. If the wiring is correct, then check the power supply. If the power supply is normal Then check whether there is output at the zero position of the sensor, or simply pressurize to see if the output changes. If there is a change, the sensor is not damaged. If there is no change, the sensor is damaged. Other reasons for this could be a broken meter, or a problem with other parts of the overall system.
2. The output of the pressure transmitter does not change, but the output of the pressure transmitter changes suddenly, and the zero position of the pressure relief transmitter cannot return. The reason for this phenomenon is most likely caused by the sealing ring of the pressure sensor, which has been encountered several times in the use of our customers. Generally, due to the specification of the sealing ring (too soft or too thick), when the sensor is tightened, the sealing ring is compressed into the pressure-inducing port of the sensor to block the sensor, and the pressure medium cannot enter when the pressure is applied, but it suddenly bursts open when the pressure is too large. The sealing ring and the pressure sensor are changed by the pressure, and when the pressure is reduced again, the sealing ring returns to block the pressure inlet, and the remaining pressure cannot be released, so the zero position of the sensor cannot go down. The best way to eliminate this reason is to remove the sensor and directly check whether the zero position is normal. If it is normal, replace the sealing ring and try again. 3. The output signal of the transmitter is unstable. The reasons for the unstable signal are as follows:
(1) The pressure source itself is an unstable pressure
(2) The anti-interference ability of the instrument or pressure sensor is not strong (3) The wiring of the sensor is not strong
(4) The sensor itself vibrates very strongly (5) The sensor fails
4. The transmitter has no output when connected to electricity
Possible causes of pressure transmitters are:
(1) Wrong wiring (check both meter and sensor) (2), open circuit or short circuit of the wire itself (3), no output from the power supply or mismatch of power supply (4), damage to the meter or mismatch of the meter (5), sensor damage
5. The deviation between the transmitter and the pointer pressure gauge is large. First, the deviation is a normal phenomenon. Second, confirm the normal deviation range. The method of confirming the normal error range:
Calculate the error value of the pressure gauge. For example: the pressure gauge range is 30bar, the accuracy is 1.5%, and the minimum scale is 0.2bar. The normal error is: 30bar*1.5%+0.2*0.5 (visual error)=0.55 bar
6. The error value of the pressure transmitter. For example: the pressure sensor range is 20bar, the accuracy is 0.5%, the instrument accuracy is 0.2%, and the normal error is: 20bar*0.5%+20bar*0.2%=0.18bar The possible error range of the overall comparison should be based on the equipment with large error value The error range shall prevail. For the above example, the deviation between the sensor and the transmitter can be regarded as normal within 0.55bar. If the deviation is very large, a high-precision instrument (at least this instrument is higher than the pressure gauge and sensor) should be used for reference.
7. The influence of the installation position of the differential pressure transmitter on the zero output: Because the differential pressure transmitter has a small measurement range, the self-weight of the sensing element in the transmitter will affect the differential pressure transmitter. output, so the zero position change that occurs when the differential pressure transmitter is installed is normal. During installation, the axis of the pressure sensitive part of the transmitter should be perpendicular to the direction of gravity. If the installation conditions are limited, the zero position of the transmitter should be adjusted to the standard value after installation and fixation.
