Smart Relays | McMaster-Carr

Smaller than other PLCs, these controllers save space in your control cabinet. They combine the functionality of a relay, timer relay, and switch in one unit, so you can program simple automation jobs.

Open-Source Controllers

Combine the functionality of a PLC and the accessibility of a development board. Built around a Raspberry Pi and an Arduino-enabled microcontroller, these controllers use open-source software to make programming and troubleshooting convenient.

Input/Output Modules for
Programmable Logic Controllers

Connect switches, transmitters, actuators, and other equipment to your PLC for complex automation jobs.

Communication Modules for
Programmable Logic Controllers

Connect and communicate with multiple automation devices simultaneously, such as HMIs, motor speed controls, supervisory PCs, and additional PLC racks. These modules allow several systems to talk to one another—within your facility and beyond—letting you expand your automated processes over numerous interconnected networks.

End Plates for Programmable Logic Controllers

Used with PLCs, these end plates close off your system’s processes—telling the processor that there are no more inputs or outputs to communicate with. They also protect your modules’ circuitry from debris.

Expansion Modules for
Programmable Logic Controllers

No need to program multiple PLCs—these modules expand your automated system, keeping everything conjoined and configured on one processor. Use them when you’re out of space on your DIN rail or need additional input/output functions.

Easy-Program Logic Controllers

Design and operate up to six simultaneous programs without symbols or technical language—the on-screen instructions use simple English.

Dual-Channel DIN-Rail Mount
Multifunction Timer Relays

Control two steps of an electrical process from a single relay—with two fully independent channels and 30 different functions, these relays give you a wide range of possibilities.

Smart DIN-Rail Mount Multifunction Timer Relays

Whether installed in an electrical cabinet or hard-to-reach area, these timer relays are controlled remotely from your smartphone. They connect to your phone via a free downloadable app so you can set time delay ranges, adjust settings, and save programs.

Human-Machine Interfaces

Also known as HMIs, program these touch-screen interfaces to control PLCs, inverters, and other automated equipment.

Rugged Touchscreen Monitors

From factory floors to outdoor installations, these monitors handle tough conditions.

Smart Multifunction Monitoring Relays

Remotely control these relays through an app on your smartphone—they simultaneously monitor phase, voltage, and frequency.

IO Link Controllers and Modules

Create a system of sensors and actuators that you can remotely update, view measurements from, and receive error messages in real time.

Hand-Held IO Link Programmers

Configure any of your IO Link devices—from sensors to switches—without a PC, outlet, or separate software.

Electrical Switching and Controlling

Compact Programmable Logic Controllers