Process Instrument Calibration : Principles & Best Practices

Define key calibration terms, interpret traceability requirements, compare bench versus field calibration and loop versus instrument calibration, and assess the advantages, disadvantages, and process-importance classifications (OSHA).

Define uncertainty as dispersion of measurement values. Use ISO guidance, assess environmental effects, and compute overall accuracy via the square root of the sum of the squares.

Bench calibrations occur in the shop with external power to verify undamaged instruments in a favorable environment, while field calibrations in situ ensure proper connections and operation.

Classify instruments as critical, non-critical, or reference only to assign calibration frequencies and streamline out-of-tolerance investigations, guided by TR 91 0002.

Learn the what, why, who, and how of calibration, with essential definitions for technicians. Adapt calibration and troubleshooting to your facility, recognizing no one-size-fits-all solution.

Explore the core principles and best practices of process instrument calibration, and establish readiness before advancing to the next section.

Identify the elements of a calibration procedure and data sheet, reference pid loop and piping diagrams, instrument and project specifications, and determine initial calibration frequency with safety and status labels.

Learn how to craft a calibration procedure aligned to company format and governing documents, detailing purpose, scope, references, test procedure, equipment, safety, and approvals.

Learn to read piping and instrumentation diagrams (P&IDs), understand components, symbols, and instrumentation loops, and follow standards for documentation, system boundaries, and controlled revisions.

Understand manufacturers' specifications to select instruments for process needs and maintenance, focusing on range and accuracy, and percent of range or reading can differ with ambient conditions; consult the manufacturer.

Explore Issa symbology for piping and instrumentation drawings (nid), including instrument symbols, location indicators (primary, auxiliary, field mounted, inaccessible), controllers, PLCs, valves, actuators, and electrical or pneumatic signals.

Define temperature by linking it to the average kinetic energy of moving atoms and molecules. Explore how heat measures total kinetic energy and how molecular motion shapes temperature in matter.

Explore several temperature sensor types, including thermocouples, resistance temperature detectors, thermistors, and filled bulb sensors, with 3D models illustrating their operation.

Explore self acting temperature control valves, including normally open heating valves, normally closed cooling valves, three-port mixing or diverting valves, and learn how temperature changes drive expansion and modulate flow.

Explore resistance temperature detectors and how two-wire, three-wire, and four-wire configurations compensate lead resistance to deliver higher accuracy, repeatability, and linear output across temperature.

Demonstrates calibration of a temperature transmitter using RTD simulator (method B), comparing in-situ sensor/transmitter calibration and loop calibration with emphasis on recording outputs and staying within 0.2% tolerance.

Learn how an rtd works and how to quickly check it with a multimeter using two-, three-, or four-wire configurations, with about 109 ohms at room temperature.

Master core principles and best practices in process instrument calibration before advancing to the next section.

Learn to calibrate pressure gauges, transmitters, and switches, determine acceptability, select calibration procedures and data sheets, and isolate or return to service when calibration fails, with documentation.

Explore piezoelectric pressure gauges that detect very low pressures or small pressure changes. These devices generate an electrical charge from diaphragm strain, converting it to a signal proportional to pressure.

Shows how a pressure switch turns pressure into an electrical signal via a piston and diaphragm. Explains normally open/closed contacts, set point, reset point, differential, range, and calibration.

Learn how pressure switches sense pressure, determine trip direction, and select normally open or normally closed contacts, with a 15 psi set point demonstrated using a multimeter.

Learn to calibrate differential pressure, capacitance, and probe and ultrasonic level instruments; select procedures and data sheets; set up test equipment; isolate failed devices; return equipment to service; maintain records.

Provides bench calibration guidance for a differential pressure transmitter, detailing 0-250 in water input, 4-20 mA output, five-point checks, and zero-span adjustments.

Learn two methods for calibrating ultrasonic level transmitters: a bounce-test using a known distance and a sight-glass verification, recording readings and adjusting per the manual.

Explore major flow instrument sensor types, including differential pressure devices such as orifices, nozzles, and venturi tubes, along with magnetic, vortex, Coriolis mass, and ultrasound flow meters.

Learn how differential pressure flow meters use an orifice plate, nozzles, and venturi tubes to convert static pressure drop into flow rate, with corrections for operating conditions.

Vortex flowmeters use a bluff body to shed vortices; the frequency tracks flow velocity and is detected by ultrasound, piezoelectric, or capacitive sensors, enabling temperature-aware mass or energy flow.

Master process instrument calibration by understanding principles and best practices before you mark this course as complete.