If you need the official 2021 firmware update, visit Siemens Support Entry ID: (valid as of 2021) or contact your local Siemens distributor. Always verify your device’s exact part number, as not all 3RT841B variants support field-upgradable firmware.
For new installations in 2025 and beyond, consider moving to the SIRIUS 3RT2 series with native Profinet and automatic firmware management via TIA Portal. This article is for informational purposes based on publicly available data from Siemens as of 2021. Always refer to the latest documentation from Siemens AG before performing any firmware update. The author is not liable for any damage resulting from improper updates. 3rt841b firmware 2021
| Component | Firmware Version (2021) | Release Date | Key Fixes | |-----------|------------------------|--------------|------------| | 3RB3 Electronic Overload Relay (Basic) | V2.1.4 | March 2021 | Fixed incorrect tripping on harmonic distortion | | 3RB3 with IO-Link | V1.3.0 | June 2021 | Added ISDU parameter download stability | | AS-Interface Module for 3RT8 | V3.0.1 | September 2021 | Resolved slave address loss after power cycle | | SIRIUS Soft Starter 3RW44 (used with) | V2.2.8 | December 2021 | Profinet RT cyclic data delay fix | If you need the official 2021 firmware update,
Introduction In the world of industrial automation, the Siemens SIRIUS family of contactors and soft starters is renowned for reliability. Among these, the 3RT841B (often part of the 3RT8 series) represents a critical component for motor management and switching applications. However, a specific point of confusion for many maintenance engineers and automation technicians has been the concept of "firmware" for a device that is fundamentally electromechanical or a simple solid-state switching unit. This article is for informational purposes based on