Article number 6ES7431-1KF20-0AB0
SIMATIC S7-400, analog input SM 431, isolated 8 AI, resolution 14 bit, U/IResistor 8 AI, cycle time 0.416 ms
Supply voltage
Load voltage L+
● Rated value (DC) 24 V; Only required for supplying 2-wire transmitters
● Reverse polarity protection Yes
Input current
from load voltage L+ (without load), max. 200 mA; for 8 connected, fully controlled 2-wire transmitters
from backplane bus 5 V DC, max. 1 000 mA
Power loss
Power loss, typ. 4.9 W
Analog inputs
Number of analog inputs 8
● For voltage/current measurement 8
● For resistance measurement 4
permissible input voltage for voltage input (destruction limit), max. 18 V; 18 V continuous, 75 V for 1 ms (mark to space ratio 1:20)
permissible input current for current input (destruction limit), max. 40 mA; Permanent
Constant measurement current for resistance-type transmitter, typ. 1.67 mA
Input ranges
● Voltage Yes
● Current Yes
● Thermocouple No
● Resistance thermometer No
● Resistance Yes
Input ranges (rated values), voltages
● 1 V to 5 V Yes
— Input resistance (1 V to 5 V) 10 MΩ
● -1 V to +1 V Yes
— Input resistance (-1 V to +1 V) 10 MΩ
● -10 V to +10 V Yes
— Input resistance (-10 V to +10 V) 100 kΩ
Input ranges (rated values), currents
● -20 mA to +20 mA Yes
— Input resistance (-20 mA to +20 mA) 50 Ω
● 4 mA to 20 mA Yes
— Input resistance (4 mA to 20 mA) 50 kΩ
Input ranges (rated values), resistors
● 0 to 600 ohms Yes
Cable length
● shielded, max. 200 m
Analog value generation for the inputs
Integration and conversion time/resolution per channel
● Resolution with overrange (bit including sign), max. 14 bit; 14 / 14 / 14
● Integration time, parameterizable Yes
● Basic conversion time (ms) 52 µs
● Interference voltage suppression for interference frequency f1 in Hz none / 400 / 60 / 50 Hz
● Time constant of the input filter 15 µs
● Basic execution time of the module (all channels released) 0.42 s
Encoder
Connection of signal encoders
● for voltage measurement Yes; possible
● for current measurement as 2-wire transducer Yes
● for current measurement as 4-wire transducer Yes
● for resistance measurement with two-wire connection Yes; Line resistances are also measured
● for resistance measurement with three-wire connection Yes; Line resistances are also measured
● for resistance measurement with four-wire connection Yes
Errors/accuracies
Temperature error (relative to input range), (+/-) 0.03 %/K
Operational error limit in overall temperature range
● Voltage, relative to input range, (+/-) 0.7 %; ±0.7 % at ±1 V; ±0.9 % at ±10 V, 1 to 5 V
● Current, relative to input range, (+/-) 0.8 %; at ±20 mA, 4 to 20 mA
● Resistance, relative to input range, (+/-) 1 %
Basic error limit (operational limit at 25 °C)
● Voltage, relative to input range, (+/-) 0.6 %; 0.6 % at ±1 V; 0.75 % at ±10 V, 1 to 5 V
● Current, relative to input range, (+/-) 0.7 %; at ±20 mA, 4 to 20 mA
● Resistance, relative to input range, (+/-) 0.7 %; 0 to 600 ohms
Interrupts/diagnostics/status information
Diagnostics function No
Potential separation
Potential separation analog inputs
● Potential separation analog inputs Yes; internal/external
● between the channels No
● between the channels and backplane bus Yes
● Between the channels and load voltage L+ Yes
Isolation
Isolation tested with 2 120 V DC between bus and analog section; 500 V DC between bus and local ground; 500 V DC between analog part and L+/M; 2 120 V DC between analog part and local ground; 2 120 V DC between L+/M and local ground
Dimensions
Width 25 mm
Height 290 mm
Depth 210 mm
Weights
Weight, approx. 500 g
last modified: 3/12/2024