Industrial 4-Channel Relay Module

Jargon buster

Plain-language definitions for the technical terms used above.

baud

Baud is the signalling rate of a serial connection, often used as the speed setting for UART communication. Matching the baud rate matters because both connected devices must use the same setting for readable data.

DC

DC means direct current, where electricity flows in one constant direction, as supplied by batteries, USB ports and many plug-pack power supplies. When a product specifies DC, it runs from a DC supply rather than mains AC, so you need to provide the correct voltage and polarity.

LED

A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.

Modbus

Modbus is an industrial communication protocol used by many meters, sensors, PLCs and automation devices. When a product lists Modbus support, it is generally easier to integrate with existing industrial equipment that speaks the same protocol.

Modbus RTU

Modbus RTU is a version of the Modbus protocol that runs over serial wiring, commonly RS485. When a product lists Modbus RTU, it can connect to industrial sensors, meters or drives that use serial Modbus rather than Ethernet.

Relay module

A relay module uses an electrically controlled switch to let a low-power microcontroller control a separate circuit. It matters when switching devices that need different voltages or more current than a microcontroller pin can safely handle.

RS485

RS485 is a robust differential serial communication standard often used in factories, farms and buildings where cables may be long or electrically noisy, and it can link many devices on a single pair of wires. When a product lists RS485, it can communicate with industrial sensors, meters and control equipment over longer distances than typical hobby serial wiring.