This firmware is intended for use in "brickless" (Series III) Drill & Drop probes and provides Modbus functionality.
To select between Plus and MULTI the appropriate firmware must be loaded. The SAME physical hardware may be used as either Plus or MULTI mode. The firmware image loaded controls the behaviour.
The default temperature compensation factor is updated from previous Stage 1 (brick) firmware, the new factor is: -48.75
The ASIC salinity model (v2.2) is used for salinity sensor results. Previous Stage 1 probes used the older non-ASIC salinity model. Thus, if users swap probes between Stage 1 and 2 they may notice a significant shift in salinity results.