■ WHAT IS THIS?
A SCALE block performs linear (proportional) mapping from one numeric range to another — the same function used in PLCs, HMIs, and instrumentation systems. Chain multiple blocks together to model multi-stage signal conversions in a single view.
■ EACH SCALE BLOCK
Each block has four fields:
Input High / Low — the raw signal range entering this block.
Output High / Low — the engineering unit range leaving this block.
The output of each block automatically becomes the input of the next.
▶ FORWARD MODE
Enter a value in the input field on the left. The calculator passes it through every SCALE block in sequence and shows the final output at the bottom. Intermediate values are shown in the bubbles between blocks.
◀ REVERSE MODE
Enter a known output value on the right. The calculator works backwards through every block to find what the original input must have been. Useful for checking: "if I want 18 mA out, what raw count do I need?"
■ CLAMP ALL
When enabled, any value that exceeds the input range of a block is clipped to the nearest limit before scaling. This prevents out-of-range outputs and matches how most PLC SCALE instructions behave with limit checking enabled.
■ RESPONSIVE CHAIN
The chain wraps automatically to fit your screen. When blocks overflow to the next row, a return connector shows the signal path continuing on the next row, always left to right. The layout reflows when the screen width changes.
■ EXAMPLE — 3-STAGE SIGNAL CHAIN
Sensor → PLC → Transmitter → Control system
Block 1 0–12000 (raw ADC counts) → 0–10000 (normalised)
Block 2 0–10000 (normalised) → 0–32000 (PLC integer register)
Block 3 0–32000 (register) → 4–20 mA (analogue output)
Set blocks to 3, enter a raw ADC value, and instantly see the resulting milliamp output. Switch to Reverse and enter 12 mA to find the matching ADC count.