First, the problem phenomenon: pressure transmitter no output

Finding the cause

1, check whether the power supply of the transmitter is reversed;

2、Measure the power supply of the transmitter, whether there is 24V DC voltage;

3, if it is with a meter head, check whether the meter head is damaged (you can first short-circuit the two wires of the meter head, if it is normal after short-circuiting, it means that the meter head is damaged);

4, the ammeter will be strung into the 24V power supply circuit, check whether the current is normal;

5, whether the power supply is connected to the transmitter power input;

method settle an issue

1. Connect the power supply polarity correctly.

2, must ensure that the power supply voltage supplied to the transmitter ≥ 12V (i.e. transmitter power input voltage ≥ 12V).

3、If there is no power supply, you should check whether the circuit is disconnected and whether the detection meter is selected incorrectly (input impedance should be ≤250Ω);

4, if the meter head is damaged, it is necessary to change another meter head, if it is normal, it means that the transmitter is normal, at this time, we should check whether the other instruments in the circuit are normal.

5、Connect the power cord to the power terminal.

Second, the problem phenomenon: transmitter output ≥ 20mA

Finding the cause

1, whether the transmitter power supply is normal

2, whether the actual pressure exceeds the selected range of the pressure transmitters;

3, whether the pressure sensor is damaged, serious overload will sometimes damage the isolation diaphragm.

4, whether the wiring is loose;

5, whether the power line wiring is correct

method settle an issue

1, if the transmitter power supply is less than 12VDC, should check whether there is a large load in the circuit, the input impedance of the transmitter load should be in line with the RL ≤ (transmitter power supply voltage - 12V) / ( 0.02A) Ω

2、Re-select the appropriate range of the pressure transmitter.

3、Pressure sensor, if damaged, need to be sent back to the manufacturer for repair.

4、Connect the line and tighten it.

5, the power cord should be connected to the appropriate terminal.

Third, the problem phenomenon: transmitter output ≤ 4mA

Finding the cause

1, whether the transmitter power supply is normal

2, whether the actual pressure exceeds the selected range of the pressure transmitter;

3, whether the pressure sensor is damaged, serious overload will sometimes damage the isolation diaphragm.

method settle an issue

1, transmitter power supply if less than 12VDC, should check whether there is a large load in the circuit, transmitter load input impedance should be consistent with the RL ≤ (transmitter power supply voltage - 12V)/( 0.02A) Ω .

2、Re-select the appropriate range of the pressure transmitter.

3、Pressure sensor, if damaged, need to be sent back to the manufacturer for repair.

IV. Problem phenomenon: incorrect pressure indication

Finding the cause

1、Whether the power supply of the transmitter is normal

2, reference to the pressure value must be correct

3、Is the range of the pressure indicator consistent with the range of the China pressure transmitter?

4、Is the input of the pressure indicator and the corresponding wiring correct?

5, the input impedance of the transmitter load should be consistent with RL ≤ (transmitter supply voltage - 12V) / ( 0.02A) Ω

6、Multi-point paper recorder is not recorded when the input is open circuit;

7, whether the corresponding equipment shell grounding

8, whether the AC power supply and other power supply separate lines

9, whether the pressure sensor is damaged, serious overload will sometimes damage the isolation diaphragm.

10, whether there is sand in the pipeline, impurities and other blockage of the pipeline, impurities will make the measurement accuracy is affected;

11, whether the temperature of the pipeline is too high, the use of the pressure sensor temperature is -25 ~ 85 ℃, but the actual use of -20 ~ 70 ℃ or less.

method settle an issue

1、Transmitter power supply if less than 12VDC, should check whether there is a large load in the circuit, the input impedance of the transmitter load should be consistent with the RL ≤ (transmitter power supply voltage - 12V)/( 0.02A) Ω.

2、If the accuracy of the reference pressure gauge is low, it is necessary to change another pressure gauge with higher accuracy.

3. The range of the pressure indicating instrument must be the same as the range of the low cost pressure transmitter.

4, the input of the pressure indicating instrument is 4 ~ 20mA, the transmitter output signal can be directly accessed; if the input of the pressure indicating instrument is 1 ~ 5V, the pressure indicating instrument must be connected to the input of the precision of the instrument in one thousandth and above, the resistance value of 250Ω resistor, and then access to the input of the transmitter.

5, the input impedance of the transmitter load should be in line with RL ≤, if not in line with the different measures that can be taken according to its different: such as increasing the supply voltage (but must be lower than 36VDC), reduce the load.

6、Multi-point paper recorder is not recorded when the input is open-circuit, then: 1, can not take other loads; 2, change to other no record when the input impedance ≤ 250Ω recorder.

7, the corresponding equipment shell grounding.

8, and AC power supply and other power supply separate wiring.

9, the pressure sensor is damaged, need to be sent back to the pressure transmitter manufacturer for repair.

10, the pipeline sand, impurities and other blockage of the pipeline, you need to clean up impurities, and in front of the pressure interface with a filter.

11, the pipeline temperature is too high, plus buffer tube to dissipate heat, add some cold water in the buffer tube before use, in order to prevent overheating of steam directly impact the sensor, thereby damaging the sensor or reducing the service life!