Free engineering tool
PLC Analog Scaling Calculator
Scale raw PLC analog values such as 0–27648 to engineering units—quickly, transparently, and directly in your browser.
Calculator
On a Siemens input configured for 4–20 mA, 4 mA maps to raw 0 and 20 mA maps to raw 27648.
For example bar, °C, l/min, or %.
Scaled value: 5 bar
Result
Scaled value
5 bar
Normalized position
50 %
Range status
Within nominal range
Input value
13,824
Linear formula used
y = y₀ + (x − x₀) × (y₁ − y₀) / (x₁ − x₀)
The range status evaluates the configured scaling endpoints. Hardware diagnostics such as wire break, underflow, and overflow are module-specific and must be evaluated separately.
Formula and calculation method
This calculator maps a raw value linearly onto any engineering range. The inverse direction determines the PLC count required for a physical value.
Normalized: t = (raw − raw min) / (raw max − raw min)
Scaled: engineering = eng min + t × (eng max − eng min)
Inverse: raw = raw min + (engineering − eng min) × (raw max − raw min) / (eng max − eng min)
Assumptions and limitations
- For correctly configured Siemens current channels, the nominal range is 0…27648; with a configured 4–20 mA signal, 4 mA corresponds to raw 0 and 20 mA to raw 27648.
- Bipolar Siemens voltage ranges such as ±10 V typically use −27648…27648.
- Values outside the nominal range are extrapolated and marked as under/over-range by default. Limiting occurs only when Clamp is explicitly selected.
- Custom 0%/100% endpoints may descend for a generic inverted characteristic. To reproduce Siemens NORM_X or SCALE_X exactly, follow their MIN < MAX requirement.
- Diagnostic and overrange values depend on the exact module and configuration; its hardware manual remains authoritative.
Technical sources
Formulas and conventions were checked against these primary and manufacturer references.