1. Pressure sensor output ≥20mA
1: Whether the pressure sensor power supply is normal
If it is less than 12VDC, check whether there is a large load in the loop. The input impedance of the pressure sensor load should conform to RL≤(pressure sensor supply voltage -12V)/(0.02A)Ω
2: Whether the actual pressure exceeds the selected range of the pressure transmitter;
Re-select a pressure sensor with an appropriate range.
3: Whether the pressure sensor is damaged, severe overload can sometimes damage the isolation diaphragm.
Need to be sent back to the manufacturer for repair.
4: Whether the wiring is loose;
Connect the wire and tighten
5: Is the power cord wiring correct?
The power cord should be connected to the corresponding terminal
2. Incorrect pressure indication
1: Whether the pressure sensor power supply is normal
If it is less than 12VDC, check whether there is a large load in the loop. The input impedance of the transmitter load should conform to RL≤(transmitter supply voltage -12V)/(0.02A)Ω
2: Whether the reference pressure value must be correct
If the accuracy of the reference pressure gauge is low, another pressure gauge with higher accuracy must be replaced.
3: Whether the range of the pressure indicating instrument is consistent with the range of the pressure transmitter
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
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, it must be connected to the input end of the pressure indicating instrument with an accuracy of one thousandth One or more resistors with a resistance value of 250Ω, and then connect to the input of the transmitter.
5: The input impedance of the transmitter load should conform to RL≤(transmitter supply voltage -12V)/(0.02A)Ω
If not, corresponding measures can be taken according to their differences: such as increasing the supply voltage (but must be lower than 36VDC), reducing the load, etc.
6: Whether the input end of the multipoint paper recorder is open when it is not recording; if it is open: 1), no other load can be carried; 2), use another recorder with input impedance ≤ 250Ω when there is no recording.
7: Whether the corresponding equipment shell is grounded The equipment shell is grounded
8: Whether to separate the wiring from AC power and other power sources
9: Whether the pressure sensor is damaged, severe overload can sometimes damage the isolation diaphragm. Need to be sent back to the manufacturer for repair.
10: Whether there is sand, impurities, etc. in the pipeline that block the pipeline, which will affect the measurement accuracy when there are impurities; it is necessary to clean up the impurities and add a filter before the pressure port.
11: Whether the temperature of the pipeline is too high, the operating temperature of the pressure sensor is -25~85℃, but in actual use, it is best to be within -20~70℃. 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, which may damage the sensor or reduce its service life.
Three, the pressure sensor has no output
1: Check whether the pressure sensor power supply is connected reversely;
Connect the power polarity correctly
2: Measure whether the power supply of the pressure sensor has 24V DC voltage;
It must be ensured that the power supply voltage to the pressure sensor is ≥12V (that is, the voltage at the input end of the pressure sensor power supply is ≥12V). If there is no power supply, check whether the loop is broken, whether the detection instrument is selected incorrectly (input impedance should be ≤250Ω); etc.
3: If it is with a meter head, check whether the meter head is damaged (you can short-circuit the two wires of the meter head first, if the short circuit is normal, it means the meter head is damaged);
If the meter head is damaged, it needs to be replaced.
4: Connect the ammeter into the 24V power supply loop to check whether the current is normal;
If it is normal, the pressure sensor is normal. At this time, check whether other instruments in the loop are normal.
5: Whether the power supply is connected to the transmitter power input terminal;
Connect the power cord to the power terminal.
4. Pressure sensor output≤4mAOutput≤4mA
1: Whether the pressure sensor power supply is normal
If it is less than 12VDC, check whether there is a large load in the loop. The input impedance of the pressure sensor load should conform to RL≤(transmitter supply voltage -12V)/(0.02A)Ω
2: Whether the actual pressure exceeds the selected range of the pressure transmitter;
Reselect a pressure transmitter with appropriate range
Whether the pressure sensor is damaged, severe overload can sometimes damage the isolation diaphragm.