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/Categories/Power & Conversion/Relays & Electromechanical/I O Relay Modules

I O Relay Modules

258 products

In real industrial control systems, machines interact continuously with sensors, switches, motors, valves, and other field devices. If signal conversion between field devices and controller logic is unstable, systems can display incorrect readings, delayed responses, or unsafe output behavior. This risk increases in fast production lines and safety-monitored environments. PLC I/O modules solve this by acting as the electrical interface between field signals and PLC processing logic.

ImagePart Number / ManufacturerDescription / SpecsMOQDatasheetRFQ
73G-OV10
73G-OV10
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG OUTPUT MODULE
1
73G-IV10B
73G-IV10B
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
73G-II420
73G-II420
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
IDC5Q
IDC5Q
Manufacturer: Sensata-Crydom
Category: I O Relay Modules
DC INPUT MODULE 12-60V
1
73G-ITCK
73G-ITCK
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
73G-OV5
73G-OV5
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG OUTPUT MODULE
1
5535868
5535868
Manufacturer: Phoenix Contact
Category: I O Relay Modules
OUTPUT MODULE
1
73G-OI420
73G-OI420
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG OUTPUT MODULE
1
73G-IV5
73G-IV5
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
73G-ITCJ
73G-ITCJ
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
73G-OI020
73G-OI020
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG OUTPUT MODULE
1
73G-IV10
73G-IV10
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
73G-IVAC120
73G-IVAC120
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
SLO48CRA4
SLO48CRA4
Manufacturer: Weidmüller
Category: I O Relay Modules
DC OUTPUT MODULE 4A
1
SLI120CR
SLI120CR
Manufacturer: Weidmüller
Category: I O Relay Modules
AC INPUT MODULE 120V
1
73G-II5000
73G-II5000
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
G3R-ODX02SN DC5-24
G3R-ODX02SN DC5-24
Manufacturer: Omron Automation and Safety
Category: I O Relay Modules
DC OUTPUT MODULE 2A
1
G3R-OD201SN DC5-24
G3R-OD201SN DC5-24
Manufacturer: Omron Automation and Safety
Category: I O Relay Modules
DC OUTPUT MODULE 1.5A
1
73G-ITR100
73G-ITR100
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG INPUT MODULE
1
73L-OI420
73L-OI420
Manufacturer: Grayhill Inc.
Category: I O Relay Modules
ANALOG OUTPUT MODULE
1
Showing 1-20 of 258 results

Applications of PLC I/O Modules

  • Factory automation sensor and actuator interface systems
  • Process industry signal monitoring and control systems
  • Machine automation and robotic control signal interfaces
  • Power plant and energy distribution signal monitoring systems
  • Water treatment plant control signal interface systems
  • Material handling and conveyor sensor interface systems
  • Industrial safety monitoring and interlock signal systems

Key Technical Specifications

  • Input and output signal type such as digital or analog
  • Channel count and signal density per module
  • Input voltage range and output drive capability
  • Signal isolation rating and noise immunity capability
  • Communication interface compatibility with PLC base unit
  • Operating temperature and environmental rating
  • Mounting method such as DIN rail or rack mount

Types of PLC I/O Modules

  • Digital input PLC I/O modules
  • Digital output PLC I/O modules
  • Analog input PLC I/O modules
  • Analog output PLC I/O modules
  • Mixed signal combination PLC I/O modules

Lifecycle and Replacement Considerations

PLC I/O modules are typically selected during early automation system wiring and control design because field wiring layout, control logic mapping, and signal conditioning depend on module specifications. When a PLC I/O module reaches end-of-life, replacement can be difficult if signal conditioning behavior, isolation rating, or channel mapping changes.

This is common in industrial systems that remain operational for more than ten years. Maintenance teams often require the same I/O module models to avoid rewiring or control program modification. Even small signal timing or electrical tolerance differences can affect process stability.

Delays in sourcing compatible PLC I/O modules can lead to production downtime and increased maintenance cost.

Maketronics assists global engineering and procurement teams with reliable sourcing of both active and obsolete PLC I/O Modules.

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FAQs

What is a PLC I/O module?

A PLC I/O module connects field devices to a PLC by converting sensor signals into readable data and controller commands into actuator control signals.

What is the difference between digital and analog I/O modules?

Digital modules handle on/off signals, while analog modules process variable signals such as temperature, pressure, or flow levels.

Why is signal isolation important in PLC I/O modules?

Isolation protects the controller from electrical noise, voltage spikes, and ground loop issues, ensuring reliable system operation.

What should be considered when replacing a PLC I/O module?

Signal compatibility, isolation rating, channel mapping, and communication compatibility must be verified to maintain system stability.