Product Overview

• Siemens S7-1200 Digital Input Module
  Part Number: 6ES7221-1BH32-0XB0

  Parameter	Details
  Product Family	SM 1221 Digital Input Module
  PLC Series	SIMATIC S7-1200
  Digital Inputs	16 DI
  Input Voltage	24 V DC
  Input Type	Sink / Source
  Mounting	DIN Rail (right side of CPU)
  Dimensions	45 × 100 × 75 mm
  Operating Temperature	-20°C to +60°C
  Protection	IP20

  Description:
  This module is an expansion digital input module used with the Siemens S7-1200 PLC to increase the number of input signals. It provides 16 digital inputs operating at 24 V DC and supports both sink and source wiring configurations.
  Typical Applications
  Push buttons
  Limit switches
  Proximity sensors
  Float switches
  Digital status signals from field devices

  Example PLC Expansion

  Module	Part Number
  Digital Input 16DI	6ES7221-1BH32-0XB0
  Digital Output 16DO	6ES7222-1BH32-0XB0
  Analog Input 4AI	6ES7231-4HD32-0XB0
  Analog Output 2AO	6ES7232-4HB32-0XB0

Siemens S7-1200 Digital & Analog I/O Module Part Numbers

1. Digital Input Modules (SM 1221)

Module	Description	Part Number
SM 1221	8 Digital Input, 24V DC	6ES7221-1BF32-0XB0
SM 1221	16 Digital Input, 24V DC	6ES7221-1BH32-0XB0
SM 1221	16 Digital Input (AC)	6ES7221-1EF32-0XB0

These modules provide 24VDC sink/source digital inputs for sensors and switches.

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2. Digital Output Modules (SM 1222)

Module	Description	Part Number
SM 1222	8 DO, 24V DC transistor	6ES7222-1BF32-0XB0
SM 1222	16 DO, 24V DC transistor	6ES7222-1BH32-0XB0
SM 1222	8 DO relay	6ES7222-1XF32-0XB0
SM 1222	16 DO relay	6ES7222-1HF32-0XB0

Used for controlling contactors, solenoid valves, relays, etc.

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3. Digital Input / Output Combined Modules (SM 1223)

Module	Description	Part Number
SM 1223	8DI / 8DO (24VDC)	6ES7223-1QH32-0XB0
SM 1223	16DI / 16DO transistor	6ES7223-1BL32-0XB0
SM 1223	16DI / 16DO relay	6ES7223-1PL32-0XB0

These modules provide mixed digital inputs and outputs in one module.

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Analog Modules

4. Analog Input Modules (SM 1231)

Module	Description	Part Number
SM 1231	4 AI (Voltage / Current)	6ES7231-4HD32-0XB0
SM 1231	8 AI (Voltage / Current)	6ES7231-4HF32-0XB0
SM 1231	4 AI High-resolution	6ES7231-5ND32-0XB0
SM 1231	4 AI Thermocouple	6ES7231-5QD32-0XB0
SM 1231	4 AI RTD	6ES7231-5PD32-0XB0

Used for 4-20 mA transmitters, 0-10V sensors, temperature sensors, etc.

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5. Analog Output Modules (SM 1232)

Module	Description	Part Number
SM 1232	2 AO (0-10V / 4-20mA)	6ES7232-4HB32-0XB0
SM 1232	4 AO	6ES7232-4HD32-0XB0

Used for controlling VFD speed reference, valve position, etc.

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6. Analog Input / Output Combined Modules (SM 1234)

Module	Description	Part Number
SM 1234	4AI / 2AO	6ES7234-4HE32-0XB0
SM 1234	2AI / 2AO (Signal board type)	6ES7234-5HD30-0XB0