RS 485 (Recommended Standard 485) is an interface standard for serial data transmission that was specifically developed for industrial environments with longer transmission distances and higher immunity to interference. Unlike RS-232, RS-485 uses differential signal transmission, in which the signal is transmitted as a voltage difference between two conductors (A/B).
Technical Specifications
RS-485 is designed for multipoint connections, allowing multiple devices (often up to 32 or more with repeaters or modern drivers) to operate on a single bus line. Differential transmission makes the interface less susceptible to electromagnetic interference and allows for longer cable lengths and higher data rates than with simple, ground-referenced interfaces.
Practical Experience in Measurement Technology and at Delphin
In industrial measurement technology, RS-485 is frequently used as the physical basis for fieldbuses such as Modbus-RTU and is particularly well-suited for distributed measurement points and long cable runs. Delphin measurement and data acquisition systems can also be integrated into existing bus structures via appropriate interfaces and protocols (such as Modbus-RTU based on RS-485) to receive sensor signals or transmit measurement data to higher-level systems.