How to calibrate pressure transmitters and pressure gauges?
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How should pressure transmitters and pressure gauges be calibrated after installation? Could you explain it in detail? If there are any relevant materials, you could also recommend them. Thank you!
1. Mainstream imported smart pressure transmitters generally don’t have major issues; if they follow a certain protocol, a corresponding handheld device can be used for comparison. 2. If that’s not the case, the transmitter needs to be disassembled and compared using a pressure calibration pump or a standard gauge. In some transmitters, if the operating temperature of the medium does not match that of the transmitter, soft faults may occur – such transmitters work fine during calibration but fail in actual use (especially in low or high temperatures)
The calibration of a pressure transmitter after installation includes setting the zero point and the full scale. To set the zero point, no fluid should be flowing; the procedure varies depending on the brand of the transmitter, so it is necessary to refer to the instructions. The full scale is determined by the upper measurement limit of the fluid being measured; generally, this upper limit should not exceed 70% of the full scale. The specific procedures may differ among different brands, so again, the instructions should be consulted. Additionally, the range of the pressure transmitter must match that of the DCS system
Pressure transmitters are calibrated in accordance with JJG 882-2004, the Calibration Regulations for Pressure Transmitters, while pressure gauges are calibrated in accordance with JJG 52-2013, the Calibration Regulations for General Pressure Gauges, Pressure-Vacuum Gauges, and Vacuum Gauges Based on Elastic Elements.
Normally, pressure transmitters and pressure gauges are installed after being calibrated. For differential pressure transmitters with medium and small range capacities, micro-pressure transmitters, and micro-pressure gauges, installation may affect the zero point of the instrument; adjusting this zero point to return it to zero is sufficient； The impact on medium and high-pressure transmitters as well as pressure gauges after installation is negligible; they can be put into use right away.
What the poster is referring to is the regular calibration that takes place after the device has been in use for a while. A schedule for these calibrations is established according to relevant regulations; it’s usually around once a year. For critical components, such as those found on boilers or the pressure gauges in valve calibration devices, they need to be sent to higher authorities for mandatory calibration, with a cycle time of roughly six months. For other instruments that are not subject to mandatory calibration, one can establish their own calibration standards within the organization, purchase relevant calibration equipment such as pressure testing stations and standard signal generators, and with authorization from the higher-level calibration authority, carry out calibration in their own calibration laboratory.