Originally published on May 27, 2022 by Shaun Behrens
Last updated on January 23, 2024
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14 minute read
The Industrial Internet of Things is an integral part of Industry 4.0: the modern factory has IIoT sensors in just about every nook and cranny. Whether it’s a machine on the factory floor or an HVAC system, there is a sensor that can monitor it. And, just like other components in your industrial infrastructure like OT and IT, these sensors need to be monitored to make sure they’re up and running and collecting data. We’ll take a look at how to monitor IIoT sensors, but let’s first take a look at what we mean by the IIoT, what the use cases for IIoT sensors are, and the typical architecture.
What is the IIoT?
iWhat is IIoT?
IIoT stands for the Industrial Internet of Things and refers to a network of connected devices in the industrial sector. It is a subset of the Internet of Things (IoT). The defining characteristic of connected devices on IIoT networks is that they transfer data without human-to-human or human-to-computer interaction. Connected devices communicate through gateways, which are physical servers that filter data, and transmit it to other devices and software applications. Read more
The most obvious definition is that the IIoT is the IoT…but for industry. This means that the devices are specialized for use cases commonly found in factories or plants. Think of measuring the temperature of machines, or the status of a production process, or the temperature of an industrial enclosure. Because there is a wide range of requirements in manufacturing and production, there is also a wide range of use cases – in fact, there are too many to cover with just one blog article.
While these sensors are similar to commercial IoT sensors found in Smart Homes and office buildings, they do have some characteristics that set them apart. For one, industrial sensors need to be very accurate: where the variation of a fraction of a degree Celsius or a few millimeters can result in an unusable end product (just as an example), precise measurements are required about the status of machines or the environment.
Another characteristic of IIoT devices is that many of them are adapted to function in the harsh conditions found in plants and other industrial environments: examples are offshore oil rigs, where moisture is everywhere, or factory floors where there are excessive vibrations. IIoT sensors often need to be dust-resistant, shock-resistant, water-resistant, heat-resistant, and probably any other “-resistant” word you can think of.
Here are just some of the IIoT sensors that are available:
| Sensor type | Description |
| Motion sensors | Sense and measure the movement of objects or people |
| Acceleration sensors | Detect a change in velocity of an object |
| Gyroscopic sensors | Detect and measure rotation of an object |
| Environmental sensors | Measure temperature, barometric pressure, humidity, etc. |
| Location tracking sensors | Track the geographic location of an object |
| Pressure sensors | Measure force per unit area |
These are just some sensors. Here is a great list of common sensors.
Typical IIoT architecture
Commonly, the architecture in industrial technology has IIoT sensors transmitting their data to an edge gateway. Transmission can take place in several ways, including over a wired connection, but usually it is done wirelessly. Depending on factors like the geographic location of sensors, how often they send data and how much energy they consume, transmission protocols range from cellular technologies (4G and 5G) though to low power wide-area network (LPWAN) options.
Edge gateways collect this data, and if necessary, convert the protocol so that the data can be sent to ERP and other analytic systems.
What is the IIoT used for?
What is the purpose of the IIoT? The short answer: data. IIoT sensors collect all kinds of data from machines, buildings, and vehicles. This data is analyzed by analytics software and used to manage and optimize operations.
The insights and information gained from IIoT data can be used for various purposes. Here are just some examples:
| Purpose | Description |
| Predictive maintenance | Historical and real-time data can help engineers and technicians know when to service machines. A very simple example: if a machine usually needs service after a certain number of rotations of its motor, then measuring the total number of rotations over time will indicate when it’s best to perform the maintenance – before a problem occurs. To demonstrate a more complex use case, here's a great real-life example about how Caterpillar used sensors on ships: IoT And Big Data At Caterpillar: How Predictive Maintenance Saves Millions Of Dollars |
| Automation of processes | Automation means certain actions are automatically performed based on input received from the factory floor and other areas. But implementing automation requires data. IIoT sensors can deliver important information required by automation processes. |
| Facilities management | Collecting data about the state of the factory building helps identify when building maintenance is needed, prevent damage (such as from gas or water leaks), and manage resources like energy consumption of the facility. |
| Reducing energy consumption | IIoT sensors can measure the power consumption of specific machines or even entire circuits. Based on this data, strategies can be put in place to become more energy efficient. |
| Measuring environmental metrics | The operation of machinery sometimes requires specific environmental metrics. Specialized environmental IIoT sensors monitor metrics like temperature, humidity, barometric pressure, air quality, and more. This data is required for use cases when environmental conditions should not exceed certain thresholds. For example: some machines need specific conditions to operate, certain raw materials for production need to be stored at low temperatures, and so on. |
| Retrofitting older machines | As factories and plants move toward digitalization, it might makes sense to update old machines instead of buying newer ones. IIoT sensors can be used to make old machines “smart” by collecting and transmitting data about them. |
| Ensuring safety | IIoT sensors can detect hazardous conditions, such as gas leaks, poor air quality, smoke and more. |
Monitoring IIoT sensors
Due to their importance in industrial infrastructure, IIoT sensors need to be monitored, primarily to ensure that they are up and transmitting data as they should be. In some cases, it is also possible to get data that the sensor is measuring into your monitoring concept. There are several ways to monitor these sensors:
- Use webhook functions to get data from an IIoT sensor. Webhooks are usually triggered by some event to send information to a predefined URL. This data can then be incorporated into a monitoring dashboard.
- Monitor using the transmission protocol. OPC UA is a common choice, because it not only defines the transmission method, but also the data structure. Another popular protocol is MQTT. Let’s take MQTT as an example:
Sensors connect to an MQTT broker, and messages are published and received between sensors connected to the broker.
If you have access to MQTT, you can get information about MQTT devices that are not responding, the health of the broker, and even payload information sent by the devices.
And of course, as we’re always saying, the bigger picture is important. Bringing IIoT data into a larger monitoring concept that also includes OT and IT is not just beneficial, but necessary. Paessler PRTG monitoring software gives you tools to monitor right across your industrial environment, including IIoT devices. For more information, refer to our page about monitoring industrial environments with PRTG.
Do you have any questions about IIoT sensors? Let me know in the comments below and I'll try answer them.
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