Digital Input Modules

A digital input module is an expansion module that passes on-off signals from devices such as push buttons, limit switches, inductive sensors and relay contacts to the PLC. When the built-in inputs on the CPU are not enough, it is used in machine and line automation to bring position, status and fault information collected from the field into the program. This category includes models with 8, 16 and 32 channels and inputs that connect to NPN, PNP or both types, from the ABB AC500 and AC500-eCo series, the Delta Electronics DVP, AX-5 and R1 series, and GMT GXM modules. Select the module according to your PLC's series, the channel count, whether the input voltage matches your field supply, whether the input type (sink or source) suits the PNP or NPN output of your sensor, and the response time. A standard digital input is not a substitute for a high-speed input module made for encoder and high-frequency pulse counting; for such signals, see the high-speed I/O modules.

Products

How to choose Digital Input Modules

A digital input module is an expansion module that passes on-off signals from devices such as push buttons, limit switches, inductive sensors and relay contacts to the PLC. When the built-in inputs on the CPU are not enough, it is used in machine and line automation to bring position, status and fault information collected from the field into the program.

  • Separate sensing, motion control, logic processing and operator interface requirements.
  • Select signal type, supply voltage, communication protocol and I/O count for the machine network.
  • Verify housing size, sensing distance and PNP/NPN output polarity against the PLC input card.

Frequently asked questions

What is Digital Input Modules and where is it used?

A digital input module is an expansion module that passes on-off signals from devices such as push buttons, limit switches, inductive sensors and relay contacts to the PLC. When the built-in inputs on the CPU are not enough, it is used in machine and line automation to bring position, status and fault information collected from the field into the program.

What should I compare when choosing Digital Input Modules?

Select the module according to your PLC's series, the channel count, whether the input voltage matches your field supply, whether the input type (sink or source) suits the PNP or NPN output of your sensor, and the response time.

Where can I find technical details for Digital Input Modules products?

When the built-in inputs on the CPU are not enough, it is used in machine and line automation to bring position, status and fault information collected from the field into the program.

Digital Input Modules Selection Guide: Technical Criteria & Application Standards