Siemens 6ES7421-1BL01-0AA0

Technical specifications

Manufacturer

Siemens

Manufacturer part no.

6ES7421-1BL01-0AA0

Type

Digital input module

Application

Digital input module

Used with

SIMATIC S7-400 rack

Input current / from backplane bus 5 V DC, max.

20 mA

Power loss, typ.

6 W

Number of digital inputs

32

Digital inputs / Input characteristic according to IEC 61131

Type 1

Number of simultaneously controllable inputs / Number of simultaneously controllable inputs

32

Input voltage / Type of input voltage

DC

Input voltage / Rated value (DC)

24 V

Input voltage / for signal "0"

-30 V DC to +5 V DC

Input voltage / for signal "1"

13 V DC to 30 V DC

Input current / for signal "0", max. (permissible quiescent current)

1.3 mA

Input current / for signal "1", typ.

7 mA

Input delay (for rated value of input voltage) / for standard inputs / at "0" to "1", min.

1.2 ms

Input delay (for rated value of input voltage) / for standard inputs / at "0" to "1", max.

4.8 ms

Input delay (for rated value of input voltage) / for standard inputs / at "1" to "0", min.

1.2 ms

Input delay (for rated value of input voltage) / for standard inputs / at "1" to "0", max.

4.8 ms

Cable length / shielded, max.

1 000 m

Cable length / unshielded, max.

600 m

Connectable encoders / 2-wire sensor

Yes

Connectable encoders / 2-wire sensor / permissible quiescent current (2-wire sensor), max.

1.5 mA

Interrupts/diagnostics/status information / Diagnostics function

No

Diagnostics indication LED / Status indicator digital input (green)

Yes

Potential separation digital inputs / between the channels

No

Potential separation digital inputs / between the channels, in groups of

32

Potential separation digital inputs / between the channels and backplane bus

Yes

Isolation tested with

500 V AC/707 V DC, type test

Technical documents (1)

• Siemens data sheet 6ES7421-1BL01-0AA0

Key features

• 32 digital inputs, 24 V DC
• Signal "1" at 13 to 30 V DC, 7 mA typical
• 2-wire sensors allowed, up to 1.5 mA quiescent current
• 25 mm wide, 290 mm high module for the S7-400 rack
• Discontinued by Siemens on 1 October 2026

About the Siemens 6ES7421-1BL01-0AA0

The Siemens 6ES7421-1BL01-0AA0 is a 32-channel digital input module for the S7-400. Siemens's data sheet gives 32 isolated inputs at 24 V DC (IEC 61131 type 1), up to 1,000 m of shielded or 600 m of unshielded cable, and a 25 × 290 × 210 mm module. SiePortal shows its phase-out announced on 1 October 2025 and its product cancellation on 1 October 2026.

What is the 6ES7421-1BL01-0AA0 used for?

It reads switches, sensors and contacts into an S7-400 CPU from the S7-400 rack.

Lifecycle and successor

Discontinued.

Before you order

What to photograph or confirm so the right unit is quoted.

Check the order number on the module; S7-400 I/O modules are a different size from S7-300 modules and do not fit an S7-300 rack.