6ES7321-1BL00-0AA0

Technical specifications

Manufacturer

Siemens

Manufacturer part no.

6ES7321-1BL00-0AA0

Type

Digital input module

Application

Digital input module

Used with

SIMATIC S7-300 rack (S7-300 backplane bus)

Product function / Isochronous mode

No

Load voltage L+ / Rated value (DC)

24 V

Load voltage L+ / permissible range, lower limit (DC)

20.4 V

Load voltage L+ / permissible range, upper limit (DC)

28.8 V

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

15 mA

Power loss, typ.

6.5 W

Number of digital inputs

32

Digital inputs / Input characteristic curve in accordance with IEC 61131, type 1

Yes

Number of simultaneously controllable inputs / horizontal installation / up to 40 °C, max.

32

Number of simultaneously controllable inputs / horizontal installation / up to 60 °C, max.

16

Number of simultaneously controllable inputs / vertical installation / up to 40 °C, max.

32

Input voltage / Type of input voltage

DC

Input voltage / Rated value (DC)

24 V

Input voltage / for signal "0"

-30 to +5 V

Input voltage / for signal "1"

13 to 30V

Input current / for signal "1", typ.

7 mA

Input delay (for rated value of input voltage) / for standard inputs / parameterizable

No

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

1.5 mA

Technical documents (1)

• Siemens data sheet 6ES7321-1BL00-0AA0

Key features

• 32 digital inputs, 24 V DC, IEC 61131 type 1
• Isolated from the backplane bus by optocoupler, groups of 16
• Input delay 1.2 to 4.8 ms
• Accepts 2-wire sensors
• 40-pin front connector
• Discontinued by Siemens on 1 October 2025; spare part only

About the Siemens 6ES7321-1BL00-0AA0

The Siemens 6ES7321-1BL00-0AA0 is the SM 321 digital input module with 32 inputs at 24 V DC, IEC 61131 type 1 characteristic. Siemens's data sheet gives input delays of 1.2 to 4.8 ms, optocoupler isolation from the backplane bus in two groups of 16, 2-wire sensor support, and a 40-pin front connector for the field wiring; the module is 40 mm wide. Siemens's data sheet marks it as a spare part. Siemens names no direct successor for the order number; its route forward is migration to the S7-1500.

What is the 6ES7321-1BL00-0AA0 used for?

It reads switches, sensors and contacts into an S7-300 CPU, in the CPU's rack or in an ET 200M remote station.

Lifecycle and successor

Discontinued: product cancellation (Siemens SiePortal), spare part only.

Before you order

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

Check the order number on the module. The 40-pin front connector with the field wiring normally moves across to the replacement, so only the module needs changing.