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Data ModelModbus Term

Discrete Input (1x Registers)

A 1-bit read-only digital input — address range 10001–19999.

Definition

Discrete inputs are read-only 1-bit values that represent digital signals coming into the device — such as sensor states, switch positions, or alarm contacts. They occupy the 1x address range. A master can read but never write them; their values are determined by the hardware or the slave's internal logic.

Quick Facts

Bit size1 bit
0-based range0–65535 (in 1x table)
1-based range10001–19999
Read withFC02
WriteNot possible from master

Related Terms

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ModPackQT Modbus Glossary · Updated 2026