Siemens 6ES7321-1BH02-0AA0 SIMATIC S7-300 Digital input Module

The Siemens 6ES7321-1BH02-0AA0 is a digital input module (SM321) of the Siemens S7-300 series PLC. It has the following core features and application scenarios:
Core Features
Input Channels and Types
16 digital input channels, supporting 24V DC input voltage, compatible with standard switches and two-wire proximity switches (BERO).
Input Voltage Range: Rated value 24V DC, allowable range 20.4V to 28.8V DC.
Input Signal Logic: Signal “0” corresponds to -30V to +5V, signal “1” corresponds to 13V to 30V.
Electrical Isolation and Anti-interference
Opto-coupling Isolation: The channels are isolated from the backplane bus using an optocoupler to prevent potential interference and enhance system stability.
Potential Isolation Grouping: The 16 input channels are grouped into one group, with no isolation within the group but isolation from the backplane bus.
Response Time and Delay
Input Delay (Rated Voltage):
From “0” to “1”: Minimum 1.2ms, Maximum 4.8ms.
From “1” to “0”: Minimum 1.2ms, Maximum 4.8ms.
Supports parameterized input delay to adapt to different application requirements.
Connection and Installation

Supply Voltage: The module operates at a supply voltage of 24 V DC. The permissible range for the load voltage is between 20.4 V and 28.8 V DC.

Input Voltage: The rated input voltage for signal “0” is 24 V DC, and for signal “1”, it ranges from -30 to +5 V DC.

Input Current: The maximum input current from the backplane bus is 10 mA, and for signal “1”, it is typically 7 mA.

Input Delay: The input delay is parameterizable, with a minimum of 1.2 ms and a maximum of 4.8 ms for transitioning from “0” to “1”.

Cable Length: The maximum cable length for shielded cables is 1000 m, and for unshielded cables, it is 600 m.

Encoder Connectivity: It supports 2-wire sensor connectivity with a maximum permissible quiescent current of 1.5 mA for the 2-wire sensor.

Isochronous Mode: The module does not support isochronous mode (application synchronized up to terminal).

Galvanic Isolation: It provides galvanic isolation between the channels and between the channels and the backplane bus, using an optocoupler.