S7-1200 PLC SM 1221 digital input module 6ES7221-1BH32-0XB0

Overview

• Digital inputs as supplement to the integral I/O of the CPUs
• For flexible adaptation of the controller to the relevant task
• For subsequent expansion of the system with additional inputs

Application

Digital input modules allow the connection of the controller to digital signals of the process.

This provides users with the following advantages:

• Optimum adaptation:
  With signal modules which can be mixed as desired, users can adapt their controllers exactly to the relevant task. This avoids superfluous investments. Modules with 8, 16, and 32 input/output channels are available.
• Flexibility: 
  If the task is expanded subsequently, the controller can be upgraded. Updating of the user program is extremely simple.

Function

The SM 1221 digital input signal modules convert the level of the external digital signals from the process into the internal signal level of the S7-1200 controller.