Communication Technologies In Industry: A Guide For Beginners

Introduction to Communication Technologies: A Must Know For Beginners | Part 1

What is communication in essence? It is the exchange of ideas between two or more parties. Every organism on the planet uses some form of communication. It is important to communicate to collaborate and synchronize. Similarly when the age of computers arrived, we felt the necessity to design systems which could talk to each other. When a group of devices talk to each other, it is called a Network. It can be a serial or ethernet/wireless ethernet based network. In this article we will cover the basics of concepts of communication technologies used in the industry. As this is a huge topic, it cannot be covered in one article, so, it will be a series of articles [we haven't decided on how many yet].

Serial Communication

As the name suggests, the data is sent one-by-one just like a queue of people, the data that goes in first, comes out first. There are primarily Recommended Standards or RS, RS-232, RS-485 and RS-422. Apart from these standards, there several other standards like SPI(Serial Peripheral Interface), I2C(Inter IC) and CAN(Controller Area Network), which are very rarely used in the industry.

RS-232

It is a standard where only one-on-one communication is possible. It is used in serial communication up to 50 feet with the rate of 1.492kbps. It has 3 layers: Physical, UART(Universal Asynchronous Receiver-Transmitter) and Application Layer. It is a very old standard, introduced in 1960's. Here +5V to +15V DC is considered as High or 1 in binary and -5V to -15V DC is considered as Low or 0 in binary. It is an outdated standard and is not used anywhere now.

RS-485

It is a standard which supports half-duplex. It is used in serial communication up to 4000feet with a maximum rate of 10Mbps. It has 4 layers: Physical, UART(Universal Asynchronous Receiver-Transmitter), Addressing and Application Layer, as it supports communication with multiple devices. It has 2 wire and 4 wire connection methodology. In 2 wire communication, bus topology is used and up to 32 nodes/devices can be connected. Again, it is a very old standard, introduced in 1980's. Here +5V to +15V DC is considered as High or 1 in binary and -5V to -15V DC is considered as Low or 0 in binary. It is a popular standard as it is very cost effective however more and more companies are opting for parallel communication.

RS-422

It is a standard which RS-422 supports full-duplex communication, meaning it can send and receive data simultaneously. However, it achieves this using 4-wire connections (two pairs of wires, one for transmitting and one for receiving). Just like RS-485, it is used in serial communication up to 4000feet with a maximum rate of 10Mbps. Unlike RS-485, which supports multi-point communication with multiple devices on a bus, RS-422 is primarily a point-to-point standard. It does support one transmitter and up to 10 receivers in a multi-drop configuration, but it doesn't have the same multi-device capabilities as RS-485. Again, it is a very old standard, introduced in 1970's. The differential voltage range for RS-422 is around +5V to +12V (positive differential voltage for a "1" or high) and -5V to -12V (negative differential voltage for a "0" or low). It is not a popular standard.

Ethernet

You must be wondering that this is a mistake right?

But no, ethernet is a type of serial communication, the data is sent and received serially, the only difference here is that it is basically either 4 wire or 8 wire communication depending on whether it CAT6 or CAT5. However there are more layers and follows OSI model(7 layers), which is topic for a different day. This allows more customization, efficient communication and more topologies that support larger networks. The speed of communication goes up to Gigabits which is significantly higher then the other standards of communication. In addition to this ethernet can also travel longer distances than the other standards. Just like other standards, ethernet uses differential signalling that means 0's and 1's are mirrors of each other, i.e. the range of 0's is from -5V to -1V and 1's are of the range from +1V to +5V depending on the speed that you want.

Ethernet is often used to deliver power to low power system, which is called PoE or power over ethernet. Where you can deliver power up to 90W.

These are all the standards which use electrical signals to transmit data, however in environments where there is a lot of electromagnetic interference we need a way to isolate signals from the noise, the most effective way is to transmit the data optically. This is where the next standard comes in. The popularity of this standard is growing at a very fast rate as it is value for money solution for communication apart from being very flexible and powerful.

Optical Fibre

Optical Fibre Communication is a technology that uses light to transmit data over long distances through optical fibres. These fibres are made of glass or plastic and can carry signals at high speeds with minimal signal loss, making them ideal for long-distance communication.

The core principle of optical fibre communication is total internal reflection, where light signals, typically generated by lasers or LEDs, are transmitted through the fibre. The light bounces along the fibre's inner walls, allowing data to travel over vast distances with little attenuation. Light pulses represent binary data (1s and 0s), where each pulse corresponds to a bit in the data stream. These pulses are transmitted one after the other in a serial manner through the optical fibre. The receiving end then decodes the light pulses back into electronic data.

As of 2024, this is a very expensive solution, as the infrastructure and device cost is very high. So it is only used where there is real need of electromagnetic isolation, higher data speed and great bandwidth.

These are some wired solutions for communication in the industry, however, there are lot of use cases where we need to use wireless communication. In the next blog, we will cover a few wireless communication standards and then discuss applications of each communication standards that we have mentioned in this blog and the next one. In the coming blogs we will also discuss software layer in all the standards and what industrial devices support what standards. We will also discuss some niche standards that are used in the industry for specific purposes.

So if you are interested in more such content about industrial IoT and SCADA, stay tuned with our blog.

~ Team Dicot