Terminal Straight Line (TSL) is a straight line drawn between the measurement output at zero and at full scale.
The TSL is used as a reference for stating the accuracy of a measurement device in a more practical way to help the user determine the reading accuracy. In most applications the device will be calibrated at zero and full scale.
Since the errors may be weighted to one side of the TSL, it is possible to improve on the accuracy by using the BSL as a reference, but calibration is not as straightforward as the TSL method.
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Glossary of Calibration technical terms
- BSL – Best Straight Line
- Compensated Temperature Range
- Dead Weight Tester
- NPL – National Physical Laboratory
- PPM – Parts Per Million
- Primary Pressure Reference Standard
- Secondary Pressure Standard
- Span Offset
- Traceable Calibration
- UKAS – The United Kingdom Accreditation Service
- UKAS Calibration Certificate
- Zero Offset
- Zero Tare

