Siemens PLCs SIMATIC S7-400 digital input SM 421 6ES7421-1BL01-0AA0

Supply voltage

Load voltage L+

• ● Rated value (DC)

24 V

• ● permissible range, lower limit (DC)

20.4 V

• ● permissible range, upper limit (DC)

28.8 V

Input current

from supply voltage L+, max.

120 mA

from backplane bus 5 V DC, max.

130 mA

20 mA

200 mA

80 mA

150 mA

Encoder supply

Number of outputs

2

Type of output voltage

L+ (-2.5 V)

Short-circuit protection

Yes; Electronic

additional (redundant) feed

Yes; possible

Output current

• ● Rated value

120 mA

• ● permissible range, lower limit

0 mA

• ● permissible range, upper limit

150 mA

Power loss

Power loss, typ.

5 W

6 W

6.5 W

12 W

8 W; 3.5 W (24 V DC); 6.5 W (48 V DC); 8.0 W (60 V DC)

Digital inputs

Number of digital inputs

16

32

32

16

16

Number of simultaneously controllable inputs

• ● Number of simultaneously controllable inputs

16

32

32

16

16

Input voltage

• ● Type of input voltage

DC

DC

AC/DC

AC/DC

AC/DC

• ● Rated value (DC)

24 V

24 V

• ● Rated value (UC)

120 V; 47 … 63 Hz

230 V; 120/230 V UC (47 … 63 Hz)

24 V; 24 V UC to 60 V UC (47 … 63 Hz)

• ● for signal “0”

-30 V DC to +5 V DC

-30 V DC to +5 V DC

0 to 20 V UC

0 to 40 V AC/ -40 to +40 V DC

-6 to +6 V DC/ 0 to 5 V AC

• ● for signal “1”

11 V DC to 30 V DC

13 V DC to 30 V DC

79 to 132 V AC; 80 to 132 V DC

74 to 264 V AC; 80 to 264 V DC, -80 to -264 V

15 to 72 V DC; -15 to -72 V DC; 15 to 60 V AC

Input current

• ● for signal “0”, min.

6 mA; < 6 mA

0 mA

0 mA; AC: 0 mA; DC: 0 mA

• ● for signal “0”, max. (permissible quiescent current)

1.3 mA

1 mA

6 mA; AC: 6 mA; DC: 2 mA

• ● for signal “1”, typ.

6 mA; 6 to 8 mA

7 mA

2 mA; 2 to 5 mA

10 mA; at 120 V: 10 mA AC, 1.8 mA DC; at 230 V: 14 mA AC, 2 mA DC

4 mA; 4 to 10 mA

Input delay (for rated value of input voltage)

for standard inputs

• — parameterizable

Yes

Yes

• — Rated value

0.5 ms; 0.5 / 3 / 10 / 20 ms

• — at “0” to “1”, min.

3 µs; 0.05 / 0.1 / 0.5 / 3 ms

1.2 ms

5 ms

• — at “0” to “1”, max.

4.8 ms

25 ms; 10 / 20 ms

20 ms; AC: 20 ms; DC: 15 ms

• — at “1” to “0”, min.

1.2 ms

5 ms

• — at “1” to “0”, max.

4.8 ms

25 µs

30 ms; AC: 30 ms; DC: 25 ms

Encoder connection

• ● Fixed current limitation for wire-break monitoring, min.

10 kΩ

18 kΩ; 18 kohms: Rated voltage 24 V (15 to 35 V); 39 kohms: Rated voltage 48 V (30 to 60 V)

• ● Fixed current limitation for wire-break monitoring, max.

18 kΩ

56 kΩ; Rated voltage 60 V (50 to 72 V)

Cable length

• ● shielded, max.

1 000 m; 1 000 m: 3 ms, 70 m: 0.5 ms, 30 m: 0.1 ms, 30 m: 0.05 ms

1 000 m

1 000 m

1 000 m

1 000 m

• ● unshielded, max.

600 m; 600 m: 3 ms; 50 m: 0,5 ms; 20 m: 0,1 ms; 20 m: 0,05 ms

600 m

600 m

600 m

600 m; 600 m: 3, 10, 20 ms; 100 m: 0,5 ms

Encoder

Connectable encoders

• ● 2-wire sensor

Yes

Yes

Yes

Yes

Yes

• — permissible quiescent current (2-wire sensor), max.

3 mA

1.5 mA

1 mA

5 mA; AC: 5 mA

0.5 mA; 0.5 to 2 mA

Interrupts/diagnostics/status information

Diagnostics function

Yes; Parameterizable

No

No

Yes; Parameterizable

Alarms

• ● Diagnostic alarm

Yes; Parameterizable

Yes; Parameterizable

• ● Hardware interrupt

Yes; Parameterizable

Yes; Parameterizable