Calculation sequence
Step-by-step method
- Calculate configured sensor span.
- Subtract reference value from indicated value.
- Express error as percent of span and compare with the entered tolerance.
CommissioningBeginnerControls
Sensor Calibration Calculator
Calculate sensor error, percent-of-span error, and corrected indicated value from a reference comparison.
Why it matters: A small absolute offset can be significant when evaluated against sensor span or a tight control tolerance.
Calculated result
Engineering evaluation
Sensor error relative to span (Es)2 % span
- Sensor range span (S)
- 100 selected units
- Indicated-minus-reference error (E)
- 2 selected units
- Offset-corrected indicated value (Xc)
- 60 selected units
Engineering interpretation
The sensor reads 2 selected units relative to the reference, equal to 2% of span. A single-point offset check does not establish linearity, hysteresis, repeatability, or full-range calibration.
Important limitations
- Sensor error exceeds the entered percent-of-span tolerance.
Engineering knowledge center
Understand the calculation—not just the answer
Governing relationships
S = URV−LRV
E = Xi−Xr
Es = E/S×100
Xc = Xi−E
within entered criterion when |Es| ≤ T
Current substitution
S = 100−0 = 100; E = 62−60 = 2; Es = 2% span.
Equation legend
Inputs and calculated quantities
- LRV
- Lower range value — selected units
- URV
- Upper range value — selected units
- Xr
- Reference value — selected units
- Xi
- Sensor indicated value — selected units
- T
- Entered tolerance — % span
- Es
- Sensor error relative to span — % span
- S
- Sensor range span — selected units
- E
- Indicated-minus-reference error — selected units
- Xc
- Offset-corrected indicated value — selected units
Applications
How this calculation is used
Building design
Document expected range and tolerance.
Construction
Support point-to-point and startup checks.
Commissioning
Compare indicated and reference values and record the resulting correction.
Quality controls
Assumptions and limitations
Assumptions
- Entered values represent the same stable operating condition.
- Measurements and reference values use consistent units and boundaries.
Limitations
- This is a screening and field-verification tool, not an automatic acceptance decision.
- Project criteria, manufacturer data, governing standards, and measurement uncertainty remain controlling.
Field use
Verification procedure
- Confirm the approved reference values and test boundary.
- Stabilize the system and record calibrated field measurements.
- Review calculation assumptions, uncertainty, and supporting evidence before disposition.
Common engineering mistakes
- Comparing readings taken at different loads, modes, or reference conditions.
- Treating a calculated status as proof of code, contract, or manufacturer compliance.
Technical basis
References and source standards
- NIST Technical Note 1297Guidance for evaluating and expressing measurement uncertainty, including root-sum-square combination of independent standard uncertainty components.
- ASHRAE Commissioning ResourcesCommissioning-process context for defining test methods, acceptance criteria, evidence, and owner requirements.
Engineering calculation disclaimer
These engineering tools are provided for educational, preliminary evaluation, field verification, and commissioning support. Results depend on the accuracy of user-entered information and the assumptions stated for each calculation. Every colored status and comparison is a screening indicator only; project criteria, contract requirements, applicable codes, manufacturer instructions, measurement uncertainty, and authorized engineering judgment govern. The tools do not replace project-specific engineering analysis or the judgment of a licensed professional engineer.
Read the full use and limitation statement