Siemens 6ES7221-1BH32-0XB0 SIMATIC S7-1200 SM 1221 Digital Input 16 DI 24V DC

The Siemens 6ES7221-1BH32-0XB0 is a SIMATIC S7-1200 Signal Module SM 1221 with 16 digital inputs rated at 24 V DC, supporting both Sink and Source wiring configurations. It is designed to extend the digital input capacity of S7-1200 CPUs, with inputs grouped in sets of four and parameterizable input delay filtering. All 16 inputs can be activated simultaneously at temperatures up to 60 °C.

Technical specifications:

• MLFB: 6ES7221-1BH32-0XB0
• Manufacturer: Siemens
• Product line: SIMATIC S7-1200
• Product type: SM 1221, DI 16x24 V DC
• Number of digital inputs: 16, in groups of 4
• Rated input voltage: 24 V DC
• Supply voltage range: 20.4 V to 28.8 V DC
• Signal "0" threshold: 5 V DC at 1 mA
• Signal "1" threshold: 15 V DC at 2.5 mA
• Current from backplane bus (5 V DC): max. 130 mA
• Input current per channel (from L+): max. 4 mA
• Input delay: parameterizable - 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, 12.8 ms (selectable per group of four)
• Input characteristic: IEC 61131, type 1
• Cable length: shielded max. 500 m, unshielded max. 300 m
• IP degree of protection: IP20
• Operating temperature: -20 °C to 60 °C
• Storage/transport temperature: -40 °C to 70 °C
• Dimensions (WxHxD): 45 x 100 x 75 mm
• Weight: approx. 210 g
• Power loss: typ. 2.5 W
• Potential separation: between channels, in groups of 4
• Certifications: CE, UL, cULus, CSA, FM, RCM, KC, Marine

Features and benefits:

• Supports Sink and Source wiring, allowing compatibility with both PNP and NPN field devices
• Parameterizable input delay per group of four channels reduces noise sensitivity without custom hardware
• Diagnostic alarm and LED status indicators per input enable fast fault identification
• All 16 inputs operable simultaneously across all mounting positions up to 60 °C
• Interrupt input capability allows time-critical event detection at the field level
• Front connector required, enabling wiring to be retained when the module is replaced

Applications:

• Expanding digital input capacity on SIMATIC S7-1200 CPUs in machine automation systems
• Connecting 24 V DC sensors, pushbuttons, and limit switches in manufacturing lines
• Process control panels requiring high channel-count discrete signal acquisition
• Building automation systems monitoring door contacts, flow switches, or status signals

Compliant with IEC 61131 (type 1 input characteristic). Part of the Siemens SIMATIC S7-1200 range.

Also known as: Siemens 6ES7221-1BH32-0XB0, SIMATIC S7-1200 SM 1221 DI 16x24VDC, S7-1200 digital input module.