From Fundamentals of Test Measurement Instrumentation

Overview

To calibrate temperature sensors you need a source of heat and a calibration standard. The sensor being calibrated and the standard are compared as they are exposed to the same temperature conditions provided by the heat source. To calibrate temperature signal conditioning or displays you need a standard that simulates the sensor output. Alternatively, the sensor and conditioner or display can be calibrated as a system by comparing the system output to the temperature measured by a standard that is exposed to the same temperature as the system sensor.

The overall cost of performing temperature calibrations is usually higher than for other types of calibrations. This is because of the cost of calibration equipment, the cost of calibration facilities, and the amount of time spent on the calibration. The calibration time is dictated by the time it takes the heat source to reach a set temperature and stabilize at that temperature. This may take close to one hour when using precision temperature baths, and the only way to reduce time is to provide multiple baths that are set at different temperatures. In comparison, pressure changes using dead-weight testers can be accomplished in less than a minute. The facilities required to support temperature calibration include extraction fans or fume hoods, increased air conditioning capacity, and high levels of electrical power. These facilities and the size and weight of typical calibration baths means that the sensor will have to be removed from its location to a calibration laboratory for calibration. There...

Copyright ISA—Instrumentation, Systems, and Automation Society 2006 under license agreement with Books24x7

Products & Services
Calibration Instruments
Calibration instruments use electrical signals or physical quantities to calibrate sensors and meters. Devices that produce electrical signals can serve as precise meters for sensor calibration, or send output signals to other devices.
Instrument Calibration Services
Instrument calibration services test equipment and calibrate them to various standards.  
Temperature Sensors
Temperature sensors are measurement devices that infer temperature by sensing some physical characteristic (i.e. resistance, emf or thermal radiation).
Calibration and Reference Standards
Calibration standards and reference sources include any source that can provide a reference for the calibration of an instrument or comparison of a material or component.
Pressure Sensors
Pressure sensors include all sensors, transducers and elements that produce an electrical signal proportional to pressure or changes in pressure.

Topics of Interest

Common electrical parameters that require calibration equipment include voltage, current, resistance, and capacitance. Equipment is needed to measure the outputs of transducers and signal conditioners...

Of all the sources of errors and uncertainties in thermal calibration by far the largest source of error and least understood effect is that of immersion of unit under test, and the reference...

9.3.4 Calibration Parameter Instability INS calibration parameters are not always exactly constant. Their values can change over the operational life of the INS. Specifications for calibration...

Overview Calibrating flow is essential for any transducers or measurement systems that provide information on the amount of material transferred in a given time. These measurements will usually be...

Meter manufacturers and users utilize laboratories with primary flow standards to calibrate their working flowmeter standards. Such laboratory standards are designed to have the lowest practical...