Calculator Inputs
Example Data Table
| Input (psi) | Ideal Output (mA) | Actual Output (mA) | Error (mA) | Error (% span) |
|---|---|---|---|---|
| 0 | 4.00 | 4.02 | 0.02 | 0.13 |
| 25 | 8.00 | 8.01 | 0.01 | 0.06 |
| 50 | 12.00 | 12.00 | 0.00 | 0.00 |
| 75 | 16.00 | 15.97 | -0.03 | -0.19 |
| 100 | 20.00 | 19.95 | -0.05 | -0.31 |
Formula Used
Process Span = URV − LRV
Ideal Output Span = Ideal High Output − Ideal Low Output
Actual Output Span = Actual High Output − Actual Low Output
Span Error = Actual Output Span − Ideal Output Span
Span Error (%) = (Span Error ÷ |Ideal Output Span|) × 100
Zero Error = Actual Low Output − Ideal Low Output
Gain Error (%) = ((Actual Output Span ÷ Ideal Output Span) − 1) × 100
Point Error = Actual Checkpoint Output − Ideal Checkpoint Output
How to Use This Calculator
- Enter the lower and upper process range values.
- Enter the ideal low and high output values for the calibrated signal.
- Enter the measured low and high outputs from the instrument or transmitter.
- Choose how many checkpoints you want across the range.
- Enter checkpoint outputs as comma-separated numbers in the same order.
- Set an acceptable tolerance percentage for pass or review status.
- Press the calculate button to see the result section above the form.
- Review the summary metrics, table, graph, and export files if needed.
Frequently Asked Questions
1. What is span error?
Span error is the difference between actual output span and ideal output span. It shows whether the instrument gain is high or low across the calibrated range.
2. Why does the calculator show zero error separately?
Zero error identifies offset at the lower calibration point. An instrument may have low zero error but still show poor span accuracy at the upper point.
3. What does gain error mean?
Gain error measures how much the actual output span differs proportionally from the ideal span. It is useful when diagnosing slope-related calibration issues.
4. Why are point errors useful?
Point errors reveal performance at checkpoints inside the range. They help identify nonlinearity, not just simple zero or span drift.
5. What should I enter for checkpoint outputs?
Enter measured outputs in order from the lowest input to the highest input. The count must match the selected number of checkpoints.
6. How is pass or review decided?
The status passes only when both the overall span error percentage and the maximum checkpoint error percentage stay within the chosen tolerance.
7. Can I use voltage instead of current?
Yes. Enter the correct low and high output values and change the output unit label to volts, percent, or another engineering signal unit.
8. Why is the graph helpful?
The graph compares ideal and actual output trends visually. It also shows checkpoint error percentage, making drift or calibration bias easier to spot.