Calibration of pressure controller measurement

JJG 544 refers to the "Verification Regulations for Pressure Controllers", whose full name is JJG 544-2011. It is a national metrological verification regulation approved and issued by the General Administration of Quality Supervision, Inspection and Quarantine on December 28, 2011, and implemented from June 28, 2012. The following is a detailed interpretation of JJG 544:

1、 Scope of application of the regulations
JJG 544 is applicable for the first calibration, subsequent calibration, and in-service inspection of pressure, vacuum, and pressure vacuum passive controllers (hereinafter referred to as controllers).
2、 Overview of Pressure Controller
Pressure controller is a specialized instrument for controlling pressure in industrial process measurement and control systems. Its working principle is to control and alarm the controlled pressure by the on/off action of the output contact when the input pressure reaches the set value.
Classification:
According to the type of pressure sensing element, it can be divided into diaphragm type, diaphragm box type, bellows type, spring tube type, piston type, etc.
According to whether the switching difference is adjustable, it can be divided into two types: adjustable switching difference type and non adjustable switching difference type.
According to whether the set point is adjustable, it can be divided into two types: set point adjustable type and set point non adjustable type.
Main terms:
Pressure switch: an instrument that controls and alarms the controlled pressure by the on/off action of the output contact when the input pressure reaches the set value.
Control pressure range: The pressure range that the controller can control.
Setpoint: The input pressure value at which control or alarm is desired to occur.
Switching value: The input value measured when switching from one state to another during the up stroke (or down stroke) of a positional control instrument.
High switching value: The pressure value at which the controller generates a control or alarm signal that changes when the input pressure increases.
Low switching value: The pressure value at which the controller generates a control or alarm signal that changes when the input pressure drops.
Differential gap: The difference between the switching value and the switching value at the same set point.
Set point error: The difference between the set value and the measured actual value when the output variable is output according to the specified requirements.
Set point range: A controller with adjustable set points, which refers to the difference between the maximum and minimum pressure values that can be adjusted by the set point.
IIICalibration of pressure controller measurementrequirement
Accuracy level: The accuracy level of the controller can be divided into 0.5 level, 1.0 level, 1.5 level, 2.0 level, 2.5 level, and 4.0 level.
Control.

Pressure range: For controllers with adjustable set points, the pressure control range should not be less than the specified value.

Repetitive error: The repeatability error of the controller should not exceed the specified value.
Switching difference: If the manufacturer has requirements for switching difference, follow the indicators provided by the manufacturer. If no switching difference indicators are provided, follow the following requirements:
For controllers with non adjustable switching differences, the switching difference should not exceed 10% of the range.
The controller with adjustable switching difference should have a minimum switching difference of no more than 10% of the range and a maximum switching difference of no less than 30% of the range.
Insulation resistance: Under the conditions of ambient temperature of 15 ℃ 35 ℃ and relative humidity of 45% 75%, the insulation resistance between the following terminals should not be less than 20M Ω:
Between each wiring terminal and the connecting curtain.
4Calibration of pressure controller measurementVerification method
Appearance inspection: Check whether the identification and appearance of the controller meet the requirements through tactile and visual inspection.
Voltage control range calibration: For controllers with adjustable set points, adjust the set point to the maximum (if the switching difference is adjustable, adjust the switching difference to the minimum), slowly increase the pressure until the contact is activated, and record the switching value. Adjust the set point to the minimum again, slowly reduce the pressure until the contact acts, and record the switching value. Verify whether the difference between the upper switching value of the maximum set point and the lower switching value of the minimum set point meets the regulatory requirements.
Setpoint deviation verification: Adjust the set point to the scale near the lower limit of the controller range (if the switching difference is adjustable, adjust the switching difference to the minimum). Gradually increase the pressure to the point of contact and record the switching value; Gradually reduce the pressure to the point of contact and record the switching value. Perform multiple cycles and calculate the difference between the average of the upper (lower) switching values and the set value to obtain the set point deviation.
Repetitive error verification: Based on the set point deviation verification, calculate the percentage of the absolute value of the maximum difference between the upper switching value (or lower switching value) obtained from three measurements at the same verification point and the range to obtain the repeatability error. For controllers with adjustable switching differences, it is necessary to calibrate them separately to the minimum and maximum switching differences.
Insulation resistance and insulation strength verification: Under specified environmental conditions, use an insulation resistance meter and a withstand voltage tester to verify the insulation resistance and insulation strength of the controller.
5、 Verification data processing and judgment
During the verification process, detailed records of various verification data should be kept, including the upper and lower switching values of the voltage control range, the calculation results of the set point deviation, the calculation results of repeatability error, the calculation results of switching difference, and the test values of insulation resistance and insulation strength. After the verification is completed, determine whether the controller is qualified based on the recorded data, and issue the corresponding verification certificate or verification result notification. For non-conforming projects, the reasons for non conformance should be specified for subsequent processing and improvement.

VICalibration of pressure controller measurementregulationsMeaning and Function
The implementation of JJG 544 is of great significance for ensuring the accuracy and reliability of pressure controllers. It standardizes the calibration method and data processing flow of pressure controllers, providing a scientific basis for quality control and metrological management of pressure controllers. Meanwhile, the release and implementation of this regulation have also promoted the continuous progress and development of pressure controller technology.

In summary, JJG 544 is an important national metrological verification regulation that plays a crucial role in ensuring the accuracy and reliability of pressure controllers in industrial process measurement and control systems.

Company Background Introduction:

Ze Heng The advantage of Huapu in metrology calibration, verification, and confirmation is that it focuses on providing quality control services for biopharmaceuticals. It is very familiar with some special instruments, and its main team comes from pharmaceutical companies and instrument manufacturers, who are familiar with instrument and GMP regulations. For example, our team has specially developed a fluorescence quantitative PCR instrument calibration device to replace imports, which greatly reduces the cost of fluorescence quantitative/qualitative PCR instrument calibration (far lower than other peers); We have developed an internal calibration protocol for the cell counter; Developed internal calibration procedures for cell recovery instruments; The calibration procedure of gel electrophoresis scanner was developed; We have developed integrated wireless probes for lower and higher temperatures required for temperature verification, reducing the cost of users using probes extensively and replacing imports; There are many more examples, as we all come from a biological background, we pay attention to the process requirements of every biological user, focus on biopharmaceutical instruments and equipment, and strive to "go with quality and do instrument and equipment quality control" in order to make biopharmaceuticals safer.

We work closely with other units in terms of services, including mandatory inspections, special inspections, or services that cannot be done, to help customers send and collect items on their behalf, saving time, effort, and convenience.

Ze Heng Huapu is a professional service provider dedicated to providing laboratory instrument calibration, instrument and equipment validation, and factory validation for the biopharmaceutical industry. We provide pharmaceutical clients with one-stop quality control outsourcing services for QC/QA/engineering/validation/production departments.