16 Analog Inputs, Mixed Ranges
The Siemens 6ES7431-0HH00-0AB0 is an SM 431 analog input module for the S7-400 rack, packing 16 differential inputs that handle current loops (4 mA to 20 mA, ±20 mA) and voltage ranges (±10 V, ±1 V, 1 V to 5 V) in one unit. Input resistance sits at 100 kΩ for the 1 V to 5 V and ±10 V ranges, 10 MΩ for the ±1 V range, and 50 Ω for both 4 mA to 20 mA and ±20 mA current ranges — the 50 Ω burden means a 2-wire transmitter sees negligible voltage drop.
Panel Fit and Power Budget
The module occupies a single 25 mm slot on the S7-400 rack — 210 mm deep and 290 mm high, so it clears the standard 400 mm enclosure depth with room for the backplane connector and wiring duct. It draws 100 mA max from the 5 V DC backplane bus, plus up to 400 mA from load voltage L+ when all 16 channels power 2-wire transmitters. Typical power loss is 2 W, which keeps the slot temperature rise manageable in a densely populated rack.
Accuracy and Conversion Timing
Accuracy is 0.25% of the input range for current measurements (±20 mA, 4 mA to 20 mA) and for voltage measurements on the ±1 V and ±10 V ranges; the 1 V to 5 V range is slightly looser at 0.5%. Integration time is parameterizable at 50 ms or 60 ms, matching the line frequency to reject 50/60 Hz noise. Basic conversion time is 55 ms at 50 Hz or 65 ms at 60 Hz — the module updates all 16 channels in about one second, adequate for process monitoring but not for high-speed control loops.
The 6ES7431-0HH00-0AB0 is the direct fit for any S7-400 BOM line calling for a 16-channel mixed-range analog input.