The Temperature Calibration page provides an overview of how we calibrate our temperature sensors and the equations we use to do so.  The page also includes information on:

• temperature ranges
• temperature accuracies and precisions

For information related to the temperature sensors themselves - sizing, headers, materials, design, etc. - please click on the Temperature page under Technical / Parameters. 

Applied Microsystems uses variable temperature baths to take 12 temperature points for each temperature calibration we complete.  Smaller instruments - our Micros and our Smarts - are normally calibrated in a freshwater tank; larger instruments like Pluses are calibrated in salt water tanks.  We use several Hart temperature standards as our primary and traceable references.

Applied Microsystems temperature sensors are calibrated using the following formula:

T = A + B n + C n² + D n³

Where A, B, C, and D are calibration coefficients, which are determined at the factory, and n is the raw value for the temperature as measured by the instrument.

Applied Microsystems is able to calibrate our temperature sensors to any one of the following three ranges, while still maintaining accuracy, precision and resolution specifications:

• -2 to 32 degrees centrigade
• 2 to 32 degrees centigrade
• 2 to 45 degrees centigrade

Other custom ranges are also possible; however, accuracy, precision, and resolution specifications may suffer when more extended ranges are chosen.  Contact our sales department for more details.

Temperature accuracies, precisions, resolution and response time vary by sensor type.  The following table summarizes the characteristics of each sensor.

Specifications by Sensor Type

Sensor Type	Accuracy (°C)	Precision (°C)	Response (ms)	Resolution (°C)
100 ms	+/- 0.005	+/- 0.003	100 ms	0.001
500 ms	+/- 0.005	+/- 0.003	500 ms	0.001
1000 ms	+/- 0.050	+/- 0.003	1000 ms	0.001

Many vendors of oceanographic instrumentation refer to accuracy and precision interchangeably.  They are not interchangeable.  In effect, accuracy refers to how well a sensor performs against a known third party standard.  For example, a temperature sensor may be +/- 0.001 C, as compared to a Black Stack themistor module.  Precision refers to the repeatability of the readings of a given sensor.   A sensor is precise when it repeatedly provides the same reading, regardless of how accurate that reading is.

A good analogy is a dart board.  The thrower of darts is accurate when he or she is able to reach the target, the bulls-eye.  He or she is precise if, having thrown three darts, all three land in the same location, irrespective of whether or not that location is the bulls-eye.