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Data TypesModbus Term

FLOAT64 (64-bit IEEE-754 Double)

A 64-bit double-precision float spanning four consecutive Modbus registers.

Definition

FLOAT64 provides double-precision floating-point (about 15-16 significant decimal digits) across four consecutive 16-bit registers. It is less common in Modbus than FLOAT32 but appears in high-precision metering (sub-Wh energy, calibration coefficients). Byte order applies across all four registers and must match the device specification.

Quick Facts

Precision~15–16 decimal digits
Size4 registers (8 bytes)
IEEE-754 typeDouble precision

Related Terms

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ModPackQT Modbus Glossary · Updated 2026