IoT Use Case

IoT adapters and protocol converters for sensors and field devices

Components and adapters are compact hardware modules that make existing sensors, actuators and field devices IoT-ready. They convert signals such as 4-20 mA, switching outputs or Modbus into formats such as IO-Link, Ethernet or MQTT. This allows existing equipment to be retrofitted without replacing devices or changing the control program.

  • Salzgitter Flachstahl
  • Co-Founder & CTO/CPO, Greenlyte Carbon Technologies
  • CEO, inray Industriesoftware GmbH
  • Magna Exteriors (Meerane) GmbH, Manager Automation, Magna
  • PLM-Innovation-Consultant, Liebherr-IT Services GmbH

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Who offers it

Components & adapters in practice

5 manufacturers from our partner network with 58 solution examples. Those with the most documented use in this category come first.

What it is used for

What they are used for, and with what

Based on these manufacturers' solution examples: the most common use cases and the technologies their solutions speak.

Use cases

Technologies

What to look for

What components and adapters do

Components and adapters make existing sensors, actuators and field devices IoT-ready without replacing the device itself. An adapter picks up a conventional signal, such as a 4-20 mA analog value, a switching output or a serial Modbus interface, and converts it into a format that can be forwarded over an IP network or an IoT protocol such as MQTT. This category also includes IO-Link adapters that turn analog signals into IO-Link process data, as well as modular connector and electronics components that integrate signal conversion directly into the cabling.

This makes adapters one of the simplest ways to connect existing equipment. A single measured value can be retrofitted without touching the controller or the PLC program. On older machines whose sensors still work well, this saves effort and downtime.

How they differ from edge devices and routers

An adapter translates a single signal or a few channels directly at the source. It has very little computing power and does not run its own applications. Edge devices, in contrast, combine many data sources, preprocess data and run local logic or containers. Routers provide the network connection between the machine network and cellular networks or the internet. In a typical architecture, adapters deliver the data, and an edge device or router passes it on to the platform and IT. With many signals at one location, an edge device with suitable inputs can be more economical, while for a few distributed measuring points the adapter is usually the leaner solution.

What to look for when selecting an adapter

The starting point is which signal is available and where it needs to go: analog, digital or serial on one side, Ethernet, Single Pair Ethernet, IO-Link or wireless on the other. Other criteria are the power supply, for example over the data cable, the ingress protection rating, DIN rail or field mounting and the supported protocols such as MQTT, OPC UA or HTTP. One example is the periNode adapters from Perinet, which make existing Modbus and 4-20 mA devices IoT-ready without replacement and are well suited to step-by-step retrofitting.

Frequently asked questions about components and adapters

What does a Modbus gateway do?

A Modbus gateway connects devices with a serial Modbus RTU interface to an Ethernet network or to an IoT protocol such as MQTT. It is used to integrate meters, drives, sensors or older controllers that only support Modbus RTU over RS-485. The gateway polls the device registers and makes the values available on the network without modifying the device itself.

How does an analog to IO-Link converter work?

An analog to IO-Link converter turns the signal of a conventional sensor, such as 4-20 mA, 0-10 V or a switching output, into IO-Link process data. It is plugged in between the sensor and the IO-Link master. This allows sensors without their own IO-Link interface to be integrated into an IO-Link architecture and pass their readings digitally to the controller and IT.

What is a 4-20 mA signal converter?

A 4-20 mA signal converter transforms an analog signal into another analog signal, for example 0-10 V into 4-20 mA, or isolates circuits galvanically. An IoT adapter goes one step further: it digitizes the signal and makes it available via a network protocol such as MQTT, OPC UA or IO-Link. This makes the measured value directly usable for IoT platforms and software.

What is an RS485 to Ethernet converter used for?

An RS485 to Ethernet converter brings devices with a serial RS-485 interface onto an Ethernet network. Typical examples are energy meters, drives, HVAC units or older controllers that communicate via Modbus RTU. The converter makes the data accessible over the network, often as Modbus TCP. This allows distributed legacy devices to be read centrally without laying new serial cables.

What are the benefits of a Single Pair Ethernet adapter?

A Single Pair Ethernet adapter connects sensors and field devices to the Ethernet network over a single wire pair. Data and power can run over the same slim cable. This enables IP communication right down to the sensor without an additional gateway. Single Pair Ethernet adapters can also integrate existing analog or Modbus devices and are particularly suited to retrofitting.

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