FieldengInstrumentation & Controls
4–20 mA to Percent Span
Where a live-zero current sits in its configured span. Over/under-range is not clamped.
Instrumentation & ControlsElectrical & Power
Where a live-zero current sits in its configured span. Over/under-range is not clamped.
App id: INST-01. Reference version 1.0.
How to fill it
Fill the inputs. The tool shows the outputs.
On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.
Formula
f = (I − 4 mA) / 16 mAInputs
| Name | Unit |
|---|---|
| Loop current (camera) | mA |
| Live zero (optional) | mA |
| Live full scale (optional) | mA |
Outputs
| Name | Unit |
|---|---|
| Span (hero result) | % |
| Span fraction | fraction |
Diagnose
Observations are context. They do not pass or fail a structure. See Diagnose.
| When | Observation | Severity |
|---|---|---|
loop current < 3.6 mA | Below 3.6 mA | warning |
loop current < live zero | Below live zero | caution |
loop current > 21 mA | Above 21 mA | warning |
loop current > live full | Above live full scale | caution |
loop current ≤ live full | In measurement range | info |
span fraction < 0 or span fraction > 1 | Outside configured span | caution |
Assumptions
- Leave live zero/full blank for 4–20 mA. Exact 4 mA and 20 mA remain valid.
Provenance
- Linear live-zero current loop. NAMUR NE43 fault bands are diagnostic context, not universal.