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.
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. 3rt841b firmware 2021
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. For new installations in 2025 and beyond, consider