Analog input modules can be used to connect the control to analog process signals. They are suitable for the connection of voltage and current sensors, thermocouples, resistors and resistance thermometers.

Siemens Analog Input Modules SIMATIC S7-400 Product Specifications:

Article number	6ES7431-0HH00-0AB0	6ES7431-1KF20-0AB0	6ES7431-1KF00-0AB0	6ES7431-1KF10-0AB0
	SIMATIC S7-400, ANALOG INPUT	SIMATIC S7-400, SM 431	SIMATIC S7-400, SM 431	SIMATIC S7-400, SM 431
Supply voltage
Load voltage L+
● Rated value (DC)	24 V; Only required for supplying 2-wire transmitters	24 V; Only required for supplying 2-wire transmitters	not necessary	24 V; Only required for supplying 2-wire transmitters
● Reverse polarity protection	Yes	Yes		Yes
Input current
from load voltage L+ (without load), max.	400 mA; for 16 connected, fully controlled 2-wire transmitters	200 mA; for 8 connected, fully controlled 2-wire transmitters		200 mA; for 8 connected, fully controlled 2-wire transmitters
from backplane bus 5 V DC, max.	100 mA	1 000 mA	350 mA	600 mA
Power loss
Power loss, typ.	2 W	4.9 W	1.8 W	3.5 W
Analog inputs
Number of analog inputs	16	8	8	8
● For voltage/current measurement	16	8	8	8
● For resistance measurement		4	4	4
permissible input voltage for voltage input (destruction limit), max.	20 V; 20 V DC permanent, 75 V DC for max. 1 s (duty factor 1:20)	18 V; 18 V continuous, 75 V for 1 ms (mark to space ratio 1:20)	50 V	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	40 mA; Permanent	50 mA; 40 mA continuous	40 mA; Permanent
Constant measurement current for resistance-type transmitter, typ.	1.67 mA	1.67 mA	1.67 mA	1.67 mA
Input ranges
● Voltage	Yes	Yes	Yes	Yes
● Current	Yes	Yes	Yes	Yes
● Thermocouple	No	No	No	Yes
● Resistance thermometer	No	No	No	Yes
● Resistance	No	Yes	Yes	Yes
Input ranges (rated values), voltages
● 1 V to 5 V	Yes	Yes	Yes	Yes
— Input resistance (1 V to 5 V)	100 kΩ	10 MΩ	200 kΩ	1 MΩ
● -1 V to +1 V	Yes	Yes	Yes	Yes
— Input resistance (-1 V to +1 V)	10 MΩ	10 MΩ	200 kΩ	1 MΩ
● -10 V to +10 V	Yes	Yes	Yes	Yes
— Input resistance (-10 V to +10 V)	100 kΩ	100 kΩ	200 kΩ	1 MΩ
● -2.5 V to +2.5 V				Yes
— Input resistance (-2.5 V to +2.5 V)				1 MΩ
● -250 mV to +250 mV				Yes
— Input resistance (-250 mV to +250 mV)				1 MΩ
● -5 V to +5 V				Yes
— Input resistance (-5 V to +5 V)				1 MΩ
● -500 mV to +500 mV				Yes
— Input resistance (-500 mV to +500 mV)				1 MΩ
● -80 mV to +80 mV				Yes
— Input resistance (-80 mV to +80 mV)				1 MΩ
Input ranges (rated values), currents
● 0 to 20 mA				Yes
— Input resistance (0 to 20 mA)				50 Ω
● -20 mA to +20 mA	Yes	Yes	Yes
— Input resistance (-20 mA to +20 mA)	50 Ω	50 Ω	80 Ω
● 4 mA to 20 mA	Yes	Yes	Yes	Yes
— Input resistance (4 mA to 20 mA)	50 Ω	50 kΩ	80 Ω	50 Ω
Input ranges (rated values), thermocouples
● Type B				Yes
— Input resistance (Type B)				1 MΩ
● Type E				Yes
— Input resistance (Type E)				1 MΩ
● Type J				Yes
— Input resistance (type J)				1 MΩ
● Type K				Yes
— Input resistance (Type K)				1 MΩ
● Type L				Yes
— Input resistance (Type L)				1 MΩ
● Type N				Yes
— Input resistance (Type N)				1 MΩ
● Type R				Yes
— Input resistance (Type R)				1 MΩ
● Type S				Yes
— Input resistance (Type S)				1 MΩ
● Type T				Yes
— Input resistance (Type T)				1 MΩ
● Type U				Yes
— Input resistance (Type U)				1 MΩ
Input ranges (rated values), resistance thermometer
● Ni 100				Yes
— Input resistance (Ni 100)				1 MΩ
● Ni 1000				Yes
— Input resistance (Ni 1000)				1 MΩ
● Pt 100				Yes
— Input resistance (Pt 100)				1 MΩ
● Pt 1000				Yes
● Pt 10000				Yes
● Pt 200				Yes
— Input resistance (Pt 200)				1 MΩ
● Pt 500				Yes
— Input resistance (Pt 500)				1 MΩ
Input ranges (rated values), resistors
● 0 to 48 ohms				Yes
— Input resistance (0 to 48 ohms)				1 MΩ
● 0 to 150 ohms				Yes
— Input resistance (0 to 150 ohms)				1 MΩ
● 0 to 300 ohms				Yes
— Input resistance (0 to 300 ohms)				1 MΩ
● 0 to 600 ohms		Yes	Yes	Yes
— Input resistance (0 to 600 ohms)			usable up to 500 ohms	1 MΩ
● 0 to 6000 ohms				Yes; Usable up to 5000 Ohm
— Input resistance (0 to 6000 ohms)				1 MΩ
Thermocouple (TC)
Temperature compensation
— parameterizable				Yes
— internal temperature compensation				No
— external temperature compensation with Pt100				Yes
— external temperature compensation with compensations socket				Yes
— dynamic reference temperature value				Yes
Characteristic linearization
● parameterizable				Yes
— for thermocouples				Type B, E, J, K, L, N, R, S, T, U
— for resistance thermometer				Pt100, Pt200, Pt500, Pt1000, Ni100, Ni1000
Cable length
● shielded, max.	200 m	200 m	200 m	200 m; 50 m with thermocouples and input ranges ≤ 80 mV
Analog value generation for the inputs
Integration and conversion time/resolution per channel
● Resolution with overrange (bit including sign), max.	13 bit	14 bit; 14 / 14 / 14	13 bit	14 bit; with activated filtering: 16 bit
● Integration time, parameterizable	Yes	Yes	Yes	Yes
● Basic conversion time (ms)	55 / 65 ms	52 µs	23 / 25 ms	20.1 / 23.5 ms
● Integration time (ms)	50 / 60 ms		16,7 / 20 ms	16,7 / 20 ms
● Interference voltage suppression for interference frequency f1 in Hz	50 / 60 Hz	none / 400 / 60 / 50 Hz	50 / 60 Hz	50 / 60 Hz
Encoder
Connection of signal encoders
● for voltage measurement	Yes; possible	Yes; possible	Yes; possible	Yes; possible
● for current measurement as 2-wire transducer		Yes	Yes; with external transmitter supply	Yes
● for current measurement as 4-wire transducer	Yes	Yes	Yes	Yes
● for resistance measurement with two-wire connection		Yes; Line resistances are also measured	Yes; Line resistances are also measured	Yes; Line resistances are also measured
● for resistance measurement with three-wire connection		Yes; Line resistances are also measured	Yes; Line resistances are also measured	Yes
● for resistance measurement with four-wire connection		Yes	Yes	Yes
Errors/accuracies
Operational error limit in overall temperature range
● Voltage, relative to input range, (+/-)	0.65 %; 1.0 % at 1 to 5 V; 0.65 % at ±1 V, ±10 V	0.7 %; ±0.7 % at ±1 V; ±0.9 % at ±10 V, 1 to 5 V	1 %; ±1.0 % at ±1 V; ±0.6 % at ±10 V; ±0.7 % at 1 to 5 V	0.38 %; ±0.38 % at ±80 mV; ±0.35 % at ±250 mV, ±500 mV, ±1 V, ±2,5 V, ±5 V, 1 to 5 V, ±10 V
● Current, relative to input range, (+/-)	0.65 %	0.8 %; at ±20 mA, 4 to 20 mA	1 %; at ±20 mA, 4 to 20 mA	0.35 %; ±20 mA, 0 to 20 mA, 4 to 20 mA
● Resistance, relative to input range, (+/-)		1 %	1.25 %; 0 to 500 ohms (4-conductor measurement, in range of 600 ohms)	0.5 %
● Resistance thermometer, relative to input range, (+/-)				0.5 %
● Thermocouple, relative to input range, (+/-)				TC Type B (±14.8 K), TC Type R (±9.4 K), TC Type S (±10.6 K), TC Type T (±2.2 K), TC Type E (±4.0 K), TC Type J (±5.2 K), TC Type K (±7.6 K), TC Type U (±3.5 K), TC Type L (±5.1 K), TC Type N (±5.5 K)
Basic error limit (operational limit at 25 °C)
● Voltage, relative to input range, (+/-)	0.25 %; 0.5% at 1 to 5 V; 0.25% at ±1 V, ±10 V	0.6 %; 0.6 % at ±1 V; 0.75 % at ±10 V, 1 to 5 V	0.7 %; 0.7% at ±1 V; 0.4% at ±10 V; 0.5% at 1 to 5 V	0.15 %; ±0.15 % (±250 mV, ±500 mV, ±1 V, ±2.5 V, ±5 V, 1 to 5 V, ±10 V); ±0.17% (±80 mV)
● Current, relative to input range, (+/-)	0.25 %; at ±20 mA, 4 to 20 mA	0.7 %; at ±20 mA, 4 to 20 mA	0.7 %; at ±20 mA, 4 to 20 mA	0.15 %; ±20 mA, 0 to 20 mA, 4 to 20 mA
● Resistance, relative to input range, (+/-)		0.7 %; 0 to 600 ohms	0.8 %; 0 to 500 ohms (4-conductor measurement, in range of 600 ohms)	0.15 %; ±0.15 % at 0 to 48 ohms (4-conductor measurement), 0 to 150 ohms (4-conductor measurement), 0 to 300 ohms (4-conductor measurement), 0 to 600 ohms (4-conductor measurement), 0 to 5000 ohms (4-conductor measurement, in range of 6000 ohms); ±0.3 % at 0 to 300 ohms (3-conductor measurement), 0 to 600 ohms (3-conductor measurement), 0 to 5000 ohms (3-conductor measurement, in range of 6000 ohms)
● Resistance thermometer, relative to input range, (+/-)				0.3 %
● Thermocouple, relative to input range, (+/-)				TC Type B (±8.2 K), TC Type R (±5.2 K), TC Type S (±5.9 K), TC Type T (±1.2 K), TC Type E (±1.8 K), TC Type J (±2.3 K), TC Type K (±3.4 K), TC Type U (±1.8 K), TC Type L (±2.3 K), TC Type N (±2.9 K)
Interrupts/diagnostics/status information
Diagnostics function	No	No	No	No
Potential separation
Potential separation analog inputs
● Potential separation analog inputs	No	Yes; internal/external	Yes; internal/external	Yes; internal/external
● between the channels	No	No	No	No
● between the channels and backplane bus	No	Yes	Yes	Yes
● Between the channels and load voltage L+	No	Yes		Yes
Isolation
Isolation tested with	500 V AC/707 V DC, type test	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	2 120 V DC between bus and analog part; 500 V DC between bus and local ground; 2 120 V DC between analog part and local ground	2 120 V DC between bus and L+/M; 2 120 V DC between bus and analog section; 500 V DC between bus and local ground; 500 V DC between analog section and L+/M; 2 120 V DC between analog section and local ground; 2 120 V DC between L+/M and local ground
Dimensions
Width	25 mm	25 mm	25 mm	25 mm
Height	290 mm	290 mm	290 mm	290 mm
Depth	210 mm	210 mm	210 mm	210 mm
Weights
Weight, approx.	500 g	500 g	500 g	500 g

Article number	6ES7431-7QH00-0AB0	6ES7431-7KF00-0AB0	6ES7431-7KF10-0AB0
	SIMATIC S7-400, SM 431	SM 431, 8AI, U/I/THERMO, 16BIT	SM 431, 8AI, RESIST./PT100, 16BIT,
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.	400 mA; for 16 connected, fully controlled 2-wire transmitters
from backplane bus 5 V DC, max.	700 mA	1 200 mA	650 mA
Power loss
Power loss, typ.	4.5 W	4.6 W	3.3 W
Analog inputs
Number of analog inputs	16	8	8
● For voltage/current measurement	16	8
● For resistance measurement	8		8
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)	35 V; 35 V continuous, 75 V for max. 1 s (mark to space ratio 1:20)	35 V; 35 V continuous, 75 V for max. 1 s (mark to space ratio 1:20)
permissible input current for current input (destruction limit), max.	40 mA	32 mA
Constant measurement current for resistance-type transmitter, typ.	1.67 mA		1 mA
Input ranges
● Voltage	Yes	Yes	No
● Current	Yes	Yes	No
● Thermocouple	Yes	Yes	No
● Resistance thermometer	Yes	No	Yes
● Resistance	Yes	No	Yes
Input ranges (rated values), voltages
● 1 V to 5 V	Yes	Yes
— Input resistance (1 V to 5 V)	1 MΩ	> 2 000 ohms
● -1 V to +1 V	Yes	Yes
— Input resistance (-1 V to +1 V)	1 MΩ
● -10 V to +10 V	Yes	Yes
— Input resistance (-10 V to +10 V)	1 MΩ
● -100 mV to +100 mV		Yes
● -2.5 V to +2.5 V	Yes	Yes
— Input resistance (-2.5 V to +2.5 V)	1 MΩ
● -20 mV to +20 mV		Yes
● -25 mV to +25 mV	Yes
— Input resistance (-25 mV to +25 mV)	1 MΩ
● -250 mV to +250 mV	Yes	Yes
— Input resistance (-250 mV to +250 mV)	1 MΩ
● -5 V to +5 V	Yes	Yes
— Input resistance (-5 V to +5 V)	1 MΩ
● -50 mV to +50 mV	Yes	Yes
— Input resistance (-50 mV to +50 mV)	1 MΩ
● -500 mV to +500 mV	Yes	Yes
— Input resistance (-500 mV to +500 mV)	1 MΩ
● -80 mV to +80 mV	Yes	Yes
— Input resistance (-80 mV to +80 mV)	1 MΩ
Input ranges (rated values), currents
● 0 to 20 mA	Yes	Yes
— Input resistance (0 to 20 mA)	50 Ω
● -10 mA to +10 mA	Yes	Yes
— Input resistance (-10 mA to +10 mA)	50 Ω
● -20 mA to +20 mA	Yes	Yes
— Input resistance (-20 mA to +20 mA)	50 Ω
● -3.2 mA to +3.2 mA		Yes
● 4 mA to 20 mA	Yes	Yes
— Input resistance (4 mA to 20 mA)	50 Ω	50 Ω
● -5 mA to +5 mA	Yes	Yes
— Input resistance (-5 mA to +5 mA)	50 Ω
Input ranges (rated values), thermocouples
● Type B	Yes	Yes
— Input resistance (Type B)	1 MΩ	> 2 000 ohms
● Type E	Yes	Yes
— Input resistance (Type E)	1 MΩ
● Type J	Yes	Yes
— Input resistance (type J)	1 MΩ
● Type K	Yes	Yes
— Input resistance (Type K)	1 MΩ
● Type L	Yes	Yes
— Input resistance (Type L)	1 MΩ
● Type N	Yes	Yes
— Input resistance (Type N)	1 MΩ	> 2 000 ohms
● Type R	Yes	Yes
— Input resistance (Type R)	1 MΩ
● Type S	Yes	Yes
— Input resistance (Type S)	1 MΩ
● Type T	Yes	Yes
— Input resistance (Type T)	1 MΩ
● Type U	Yes	Yes
— Input resistance (Type U)	1 MΩ
Input ranges (rated values), resistance thermometer
● Ni 100	Yes		Yes
— Input resistance (Ni 100)	1 MΩ		> 10 000 ohms
● Ni 1000	Yes		Yes; Different characteristics selectable: Europe/U.S.
— Input resistance (Ni 1000)	1 MΩ		> 10 000 ohms
● Pt 100	Yes		Yes
— Input resistance (Pt 100)	1 MΩ		> 10 000 ohms
● Pt 1000	Yes		Yes
— Input resistance (Pt 1000)	1 MΩ		> 10 000 ohms
● Pt 200	Yes		Yes
— Input resistance (Pt 200)	1 MΩ		> 10 000 ohms
● Pt 500	Yes		Yes
— Input resistance (Pt 500)	1 MΩ		> 10 000 ohms
Input ranges (rated values), resistors
● 0 to 48 ohms	Yes
— Input resistance (0 to 48 ohms)	1 MΩ
● 0 to 150 ohms	Yes
— Input resistance (0 to 150 ohms)	1 MΩ
● 0 to 300 ohms	Yes
— Input resistance (0 to 300 ohms)	1 MΩ
● 0 to 600 ohms	Yes
— Input resistance (0 to 600 ohms)	1 MΩ
● 0 to 6000 ohms	Yes; Usable up to 5000 Ohm
— Input resistance (0 to 6000 ohms)	1 MΩ
Thermocouple (TC)
Temperature compensation
— parameterizable	Yes	Yes
— internal temperature compensation		Yes
— external temperature compensation with Pt100	Yes
— external temperature compensation with compensations socket	Yes	Yes
— dynamic reference temperature value	Yes	Yes
Characteristic linearization
● parameterizable	Yes	Yes	Yes
— for thermocouples	Type B, E, J, K, L, N, R, S, T, U	Type B, E, J, K, L, N, R, S, T, U
— for resistance thermometer	Pt100, Pt200, Pt500, Pt1000, Ni100, Ni1000		Pt100, Pt200, Pt500, Pt1000, Ni100, Ni1000; different characteristics selectable (Europe/U.S.)
Cable length
● shielded, max.	200 m; 50 m with thermocouples and input ranges ≤ 80 mV	200 m	200 m; 50 m with thermocouples and input ranges ±80 mV
Analog value generation for the inputs
Integration and conversion time/resolution per channel
● Resolution with overrange (bit including sign), max.	16 bit; 16 / 16 / 16	16 bit	16 bit
● Integration time, parameterizable	Yes	Yes	Yes
● Basic conversion time (ms)	6 / 20,1 / 23,5 ms	10 / 16,7 / 20 / 100	8 / 23 / 25 ms
● Integration time (ms)	2,5 / 16,7 / 20 ms	2,5 / 16,7 / 20 / 100	20 ms at 50 Hz (entire module incl. wire break)
● Interference voltage suppression for interference frequency f1 in Hz	400 / 60 / 50 Hz	400 / 60 / 50 / 10 Hz	none/ 60 / 50 Hz
Encoder
Connection of signal encoders
● for voltage measurement	Yes; possible	Yes; possible
● for current measurement as 2-wire transducer	Yes
● for current measurement as 4-wire transducer	Yes	Yes
● for resistance measurement with two-wire connection	Yes; Line resistances are also measured
● for resistance measurement with three-wire connection	Yes		Yes
● for resistance measurement with four-wire connection	Yes	Yes	Yes
Errors/accuracies
Operational error limit in overall temperature range
● Voltage, relative to input range, (+/-)	0.3 %; ±0.3 % at ±250 mV, ±500 mV, ±1 V, ±2.5 V, ±5 V, 1 to 5 V, ±10 V; ±0.31 % at ±80 mV; ±0.32 % at ±50 mV; ±0.35 % at ±25 mV	0.3 %
● Current, relative to input range, (+/-)	0.3 %; at 0 to 20 mA, ±5 mA, ±10 mA, ±20 mA, 4 to 20 mA	0.5 %
● Resistance, relative to input range, (+/-)	0.3 %; ±0.3% at 0 to 48 Ohm (4-conductor measurement), 0 to 150 Ohm (4-conductor measurement), 0 to 300 Ohm (4-conductor measurement), 0 to 600 Ohm (4-conductor measurement), 0 to 5000 Ohm (4-conductor measurement, in range of 6000 Ohm); ±0.4% at 0 to 300 Ohm (3-conductor measurement), 0 to 600 Ohm (3-conductor measurement), 0 to 5000 Ohm (3-conductor measurement, in range of 6000 Ohm);
● Resistance thermometer, relative to input range, (+/-)	0.4 %		±1 °C
● Thermocouple, relative to input range, (+/-)	TC Type B (±11.5 K), TC Type R (±7.3 K), TC Type S (±8.3 K), TC Type T (±1.7 K), TC Type E (±3.2 K), TC Type J (±4.3 K), TC Type K (±6.2 K), TC Type U (±2.8 K), TC Type L (±4.2 K), TC Type N (±4.4 K)
Basic error limit (operational limit at 25 °C)
● Voltage, relative to input range, (+/-)	0.15 %; ±0.15% at ±250 mV, ±500 mV, ±1 V, ±2.5 V, ±5 V, 1 V to 5 V, ±10 V; ±0.17% at ±80 mV; ±0.19% at ±50 mV; ±0.23% at ±25 mV	0.1 %
● Current, relative to input range, (+/-)	0.15 %; at 0 to 20 mA, ±5 mA, ±10 mA, ±20 mA, 4 to 20 mA	0.17 %
● Resistance, relative to input range, (+/-)	0.15 %; ±0.15 % at 0 to 48 ohms (4-conductor measurement), 0 to 150 ohms (4-conductor measurement), 0 to 300 ohms (4-conductor measurement), 0 to 5000 ohms (4-conductor measurement, in range of 6000 ohms); ±0.3 % at 0 to 300 ohms (3-conductor measurement), 0 to 600 ohms (3-conductor measurement), 0 to 5000 ohms (3-conductor measurement, in range of 6000 ohms)
● Resistance thermometer, relative to input range, (+/-)	0.3 %		±0,2 °C
● Thermocouple, relative to input range, (+/-)	TC Type B (±7.6 K), TC Type R (±4.8 K) TC Type S (±5.4 K), TC Type T (±1.1 K), TC Type E (±1.8 K), TC Type J (±2.3 K), TC Type K (±3.4 K), TC Type U (±1.7 K), TC Type L (±2.3 K), TC Type N (±2.6 K)
Interrupts/diagnostics/status information
Diagnostics function	Yes; Parameterizable	Yes; Parameterizable	Yes; Parameterizable
Alarms
● Diagnostic alarm	Yes; Parameterizable	Yes; Parameterizable	Yes; Parameterizable
● Limit value alarm	Yes; Parameterizable	Yes	Yes
● Hardware interrupt	Yes; Parameterizable	Yes; Parameterizable	Yes; Parameterizable
Diagnoses
● Diagnostic information readable	Yes	Yes; possible	Yes; possible
Diagnostics indication LED
● internal fault INTF (red)	Yes
● external fault EXTF (red)	Yes
Potential separation
Potential separation analog inputs
● Potential separation analog inputs	Yes; internal/external	Yes; internal/external	Yes; internal/external
● between the channels	No	Yes	No
● between the channels and backplane bus	Yes	Yes	Yes
● Between the channels and load voltage L+	Yes
Isolation
Isolation tested with	2 120 V DC between bus and L+/M; 2 120 V DC between bus and analog section; 500 V DC between bus and local ground; 500 V DC between analog section and L+/M; 2 120 V DC between analog section and local ground; 2 120 V DC between L+/M and local ground	1 500 V DC	500 V DC
Dimensions
Width	25 mm	25 mm	25 mm
Height	290 mm	290 mm	290 mm
Depth	210 mm	210 mm	210 mm
Weights
Weight, approx.	500 g	650 g	650 g