Siemens 6ES7321-1BL00-0AA0 SIMATIC S7-300 Digital Input SM 321 32DI 24V DC

The Siemens 6ES7321-1BL00-0AA0 is a SIMATIC S7-300 Digital Input Module (SM 321) with 32 isolated digital inputs operating at 24 V DC. It connects via a 40-pin front connector and is designed for use in S7-300 PLC systems requiring high-density digital signal acquisition.

Technical specifications:

• MLFB: 6ES7321-1BL00-0AA0
• Manufacturer: Siemens
• Product line: SIMATIC S7-300
• Number of digital inputs: 32
• Rated input voltage: 24 V DC
• Permissible voltage range: 20.4 V DC - 28.8 V DC
• Signal "0" input voltage: -30 to +5 V
• Signal "1" input voltage: 13 to 30 V
• Input current for signal "1": 7 mA (typ.)
• Backplane bus current (5 V DC): 15 mA max.
• Input delay (0 to 1 / 1 to 0): 1.2 ms min. / 4.8 ms max.
• Simultaneously controllable inputs: 32 up to 40 °C, 16 up to 60 °C (horizontal); 32 up to 40 °C (vertical)
• Potential separation: between channels and backplane bus via optocoupler; grouped in sets of 16 channels
• Isolation test voltage: 500 V DC
• Cable length: 1000 m shielded / 600 m unshielded
• Compatible sensors: 2-wire sensors (max. quiescent current 1.5 mA)
• Front connector: 40-pin
• Dimensions (W x H x D): 40 x 125 x 120 mm
• Weight: approx. 260 g
• Power loss: 6.5 W (typ.)

Features and benefits:

• 32 isolated digital inputs in a single compact 40 mm wide module
• Input characteristic curve per IEC 61131, type 1 for standardized signal compatibility
• Optocoupler isolation between inputs and backplane bus for electrical protection
• Status LED indicators (green) for each digital input channel
• Supports 2-wire sensors with low permissible quiescent current
• Approved for hazardous locations, maritime applications, and carries CCC-Ex and China RoHS certifications

Applications:

• Digital signal acquisition in S7-300 PLC-controlled manufacturing systems
• Machine automation requiring high-density 24 V DC input monitoring
• Process control panels with 2-wire sensor connections
• Installations in hazardous or maritime environments requiring certified modules
• Replacement or spare part for existing SIMATIC S7-300 installations

Compliant with IEC 61131 (type 1 input characteristic). Part of the Siemens SIMATIC S7-300 range.

Also known as: Siemens 6ES7321-1BL00-0AA0, SIMATIC S7-300 SM 321 digital input module, S7-300 32DI 24V DC input module.