What it is and where it lands in a panel
The Siemens 6AG1055-1FB00-2BY1 is the SIPLUS spare-part variant of the LOGO! DM8 230R digital I/O expansion module, supplied with a conformal coating for harsher thermal and humidity exposure than the standard line.
Thermal envelope and conformal coating — the headline SIPLUS delta
Operating range runs from -40 °C to +70 °C, which is the -40 °C floor and the +70 °C ceiling that define the SIPLUS positioning; the conformal coating is what carries that span into condensing or corrosive atmospheres the standard module would not survive. For UL/cUL installations the ceiling drops to 55 °C — a real procurement detail, because a cabinet spec'd to the headline 70 °C will be rejected at UL inspection if it crosses 55 °C under UL file E120869.
Output ratings and how they actually derate
Each relay output is rated 5 A on a resistive load, with 3 A per relay above 55 °C and a 5 A / 10 A-all-four total budget under 15 s of inrush. On inductive loads the per-relay figure is 3 A dropping to 1 A above 55 °C, again with the 3 A / < 15 s inrush window — the derating curve is what governs a hot cabinet, not the 5 A headline. The module ships with no built-in short-circuit protection on the outputs, so external fusing sized to the load and the 10 A package budget is part of the wiring design.
Installation envelope and EMC class
IP20 finger-safe from the front, panel-mount only — the module is not rated for field exposure and assumes a closed cabinet.