Siemens SIMATIC S7-300 6ES7321-1CH00-0AA0 SM 321 16 DI 24-48 V AC/DC

Overview

SIEMENS SIMATIC S7-300 • DIGITAL INPUT

6ES7321-1CH00-0AA0 SIMATIC S7-300 SM 321 16-Channel Digital Input

An isolated 16-point AC/DC digital input module for S7-300 control systems.

At a Glance

Brand	Siemens
Model	6ES7321-1CH00-0AA0
Product Type	Digital input module
Core Function	16-channel 24–48 V AC/DC signal acquisition
Compatible Series	SIMATIC S7-300

16 Isolated Inputs

Reads sixteen digital input signals with channel isolation.

Flexible Signal Voltage

Supports 24 to 48 V AC or DC input circuits.

Per-Channel Indication

Each channel has a green input-status LED.

Product Overview

6ES7321-1CH00-0AA0 is the SM 321 digital input module for SIMATIC S7-300. Its sixteen electrically isolated inputs accept 24 to 48 V AC or DC field signals.

The module indicates each channel state with a green LED. The official module data specifies no diagnostic functions or interrupt functions for this variant.

Ordering focus: confirm the input voltage, channel wiring arrangement and matching S7-300 front connector.

Key Functions

Field Signal Acquisition

Brings sixteen AC/DC binary signals into the S7-300 controller.

Channel Isolation

Provides electrical separation of input channels and the backplane bus.

Local Status Check

Displays each input state on a green channel LED.

Official Specifications

Number of Inputs	16
Rated Input Voltage	24–48 V AC/DC
Channel Electrical Isolation	Yes
Channel Isolation Group	16 channels
Isolation Test Voltage	500 V DC
Backplane Current Consumption	10 mA maximum
Typical Module Power Loss	3.5 W
Status Display	1 green LED per channel
Interrupt Functions	None
Diagnostic Functions	None
Maximum Channels in Vertical Mounting at 40 °C	16
Nominal AC Frequency	50/60 Hz

Official source:Siemens S7-300 module data, SM 321 DI 16 × UC 24/48 V section.

Frequently Asked Questions

What field signals can 6ES7321-1CH00-0AA0 read?

It reads digital signals from 24 to 48 V AC or DC input circuits.

How many inputs does 6ES7321-1CH00-0AA0 provide?

It provides sixteen isolated digital inputs.

Does 6ES7321-1CH00-0AA0 show each channel state?

A green LED indicates the state of each input channel.

Can 6ES7321-1CH00-0AA0 report channel diagnostics?

The equipment manual lists no diagnostic functions for this module.

Does 6ES7321-1CH00-0AA0 generate input interrupts?

The equipment manual lists no interrupt functions for this module.

What is the backplane current draw of 6ES7321-1CH00-0AA0?

The maximum backplane current consumption is 10 mA.

What should I verify before wiring 6ES7321-1CH00-0AA0?

Check the field voltage, input isolation arrangement and front connector against the S7-300 wiring plan.

Compatibility & Ordering Notes

Before ordering 6ES7321-1CH00-0AA0: match the 24–48 V AC/DC sensor supply, connector and channel count to the PLC hardware design.

S7-300 input checklist

• Confirm all sixteen input signal levels are within the supported AC/DC range.
• Select and wire the correct S7-300 front connector for the installed module.
• Do not rely on channel diagnostic messages from this variant.

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