As is the case most of the time, the instructor learns as much or more as the student about a topic due to the preparation work involved. In studying drum level applications, I have to say I have already have learned a lot and our presentation isn’t finished yet. There are so many details that must be considered to accurately test and calibrate a drum level transmitter – it is not just a simple vent the low side port and exercise the high to check the 4 to 20 mA output.
Consideration must be given to the types of connections, typically capillary isolation diaphragms (fill fluids, seal size, capillary tube diameter and installation issues are just some of the “gotchas”), venting on the low side can be a real issue, is there vapor at the top vs. liquid, the range is not zero-based (typically an odd negative pressure to an odd positive pressure), precise height estimates, complex engineering calculations, process temperature vs. ambient temperature during testing, and on and on.
In a typical process plant, more than 60 percent of instrument applications involve pressure. Pressure instrumentation maintenance is a critical and daily task, yet proper procedures for managing and calibrating these instruments are often overlooked or not understood. To watch Part 1 of this webinar series, click this link.
I&E Technicians need to have a good understanding of their specific application. It is not unusual to involve a process control engineer to properly estimate calibration offsets via calculations dealing with specific gravity, temperature and more. Finally, after performing a calibration, it is critical to make some common sense checks to ensure proper measurements are being made.
Calibration of pressure instruments definitely involves not only an understanding of the basics, but experience with complex applications is needed.
Calibration Resource List
How Often Do Measurements Need to Be Calibrated?
Just in Time, or Just Too Late? A Kaizen Approach to Calibration
How to Improve Industrial Productivity with Loop Calibration
Temperature Calibration: Using a Dry Block to Calculate Total Uncertainty
How Can Advanced Calibration Strategies Improve Control Performance?
How to Calibrate a Pressure Transmitter
Uncertainty in Calibration
Calibration Uncertainty and Why Technicians Need to Understand It
How to Avoid the Most Common Mistakes in Field Calibration
Learn Advanced Techniques in Field Calibration
How to Build an Industrial Calibration System Business Case
How to Use Calibration Tools for Accurate Process Temperature Measurement
How Does Low Flow Affect Differential Pressure Flowmeter Calibration?
Three Common Pitfalls of Pressure Calibration
How to Calibrate Differential Pressure Flowmeters
ISA Industrial Calibration Worksheets
Measurement Uncertainty Analysis Excel template plus book excerpt
Calibration Handbook of Measuring Instruments book excerpt
In-Depth Guide to Calibration for the Process Industries eBook
Calibration Uncertainty for Non-Mathematicians white paper