Calibrating the zero point and range of a pressure transmitter is an important step in ensuring its measurement accuracy. The following are specific calibration methods:

preparation

Standard pressure source: capable of providing accurate pressure values, with an accuracy higher than that of the calibrated pressure transmitter.

Precision digital pressure gauge: used to measure the pressure value output by a standard pressure source, with accuracy that meets calibration requirements.

Calibration equipment: such as handheld devices (suitable for smart pressure transmitters), which can set and adjust the parameters of the transmitter.

Connecting cables: used to connect equipment such as pressure transmitters, standard pressure sources, and precision digital pressure gauges.

Zero point calibration

Connecting devices: Connect the pressure transmitter, standard pressure source, and precision digital pressure gauge in the correct way. For intelligent pressure transmitters, it is also necessary to connect a handheld device.

Turn off the pressure source output: Ensure that the pressure transmitter is not subjected to pressure, and the pressure should be zero at this time.

Read output signal: Use a multimeter or handheld device to read the output signal of the pressure transmitter. For transmitters with 4-20mA output, the output should be 4mA; for transmitters with 0-10V output, the output should be 0V.

Zero point adjustment: If the output signal is not the value corresponding to the zero point, use a manual controller or adjustment device (such as a potentiometer) on the transmitter to adjust the zero point, so that the output signal reaches the standard zero point value.

Repeat check: Confirm again that the pressure is zero, check if the output signal is still at zero value, and if there is any deviation, continue adjusting until it is accurate.

span

Apply standard pressure: Based on the range of the pressure transmitter, apply full range pressure to the transmitter through a standard pressure source. For example, if the transmitter range is 0-1MPa, apply a pressure of 1MPa.

Read output signal: Use a multimeter or handheld device to read the output signal of the pressure transmitter at this time. For transmitters with 4-20mA output, the output should be 20mA at full range; for transmitters with 0-10V output, the output at full range should be 10V.

Adjust range: If the output signal does not match the full-scale output value, use the adjustment device on the handheld device or transmitter to adjust the range so that the output signal reaches the full-scale standard value.

Multiple calibrations: Select multiple pressure points within the range (such as 25%, 50%, 75% range, etc.), repeat the steps of applying pressure and adjusting output to ensure accurate measurement throughout the entire range.

Recording and Verification

Record calibration data: During the calibration process, record in detail the pressure values and corresponding output signal values of each calibration point for subsequent reference and analysis.

Verify calibration results: After calibration is completed, check the accuracy of the zero point and range again to ensure that the transmitter's output meets the requirements at different pressures.

Calibration of pressure transmitters requires strict adherence to operating procedures to ensure the accuracy and reliability of calibration results. If unsure about the calibration process, it is recommended to refer to the transmitter manual or consult a professional technician.