As we use multiple protocols in IT, same we use Protocols in Operational Technology (OT). in previous article or Psrt-1, we have discussed about OT introduction and other basic things. in this Part-2 we will discuss about Protocols and other features.
Operational Technology (OT) is a crucial aspect of industrial infrastructure, about a wide range of devices and systems used in manufacturing, energy, transportation, utilities, and more.
Protocols that facilitate data exchange, monitoring, and control of industrial processes.
What are OT Protocols?
OT Protocols are communication standards designed to enable seamless data transmission and interaction between various industrial devices and systems. Unlike traditional Information Technology (IT) protocols used in computer networks, OT protocols cater to the unique requirements of industrial automation and control systems.
These protocols allow sensors, actuators, Programmable Logic Controllers (PLCs), Human-Machine Interfaces (HMIs), and other industrial components to exchange data and work together efficiently
Type of ICS Protocols
There are multiple ICS Protocols in the industries, but here we will discuss about:
- Modbus
- DNP3
- Fieldbus
- Profibus
- BACnet
- OPC ( OLE for Process Control)
1. Modbus Protocols
- Modbus is one of the oldest and most popular ICS protocols in use today, largely because of it’s openness and simplicity.
- Modbus is a digital communication protocol for two or more devices to talk to one another.
- Modbus is related to the application-level protocols of the Open System Interconnection (OSI) network model.
- It has an open-source code, which allows most field controllers to support Modbus, and this has mad it very popular
- Simple protocol
- Low-cost development
- Minimum hardware requirement to support
- Master/slave protocol
- Communicates with up to 247 devices
- Uses standard TCP/IP protocols
- Error checking is done using CRC (Cyclic Redundancy Check) to ensure data integrity.
Use of Modbus
Mostly Modbus usage in below industries
- Industrial Buildings
- Commercial Buildings
- Infrastructure
- Transportation
- Energy Applications
Modbus – Master/Slave Architecture
Modbus is a serial communication protocol. As Modbus is working in Master/Slave fashion, so master send the request for data/query and Slave share the data in the form of response.
Modbus Protocol Version
Modbus has several Version, mostly are included:
- Modbus ASCII: Data is transmitted in ASCII characters and use Serial RS-232 or RS-485.
- Modbus Plus: It is a Proprietary version which use RS-485, Twisted pair and token Rotation
- Modbus RTU: Most common used then ASCII and its also use Serial RS-232 or RS-485, RS-422.
- Modbus TCP/IP: it is an encapsulated version and communicated with TCP/IP Packet on port 502.
2. Distributed Network Protocol 3 (DNP-Version 3)
- DNP3 is a communication protocol used in SCADA and remote monitoring systems.
- It is also Open Protocol
- it is also used majorly by the oil and gas, water, and wastewater sectors to communicate with distribution and transmission facilities.
- It supports communications between station computers, RTU, IED.
- Provides features and functions missing from Modbus
- It is an open protocol, therefore numerous vendors support it
- Most often uses TCP, but also supports UDP
- Uses Port 20000
- Traffic is sent in plain text
- DNP3 is typically used Master & Slave model
- It is reliable and Robust
- layered architecture similar to the OSI (Open Systems Interconnection) model. It consists of physical, data link, transport, and application layers.
3. Fieldbus Protocol
Fieldbus is a group of Protocols. It allowing to works on multiple topologies like ring, bus, star, Daisy chain.
A few of the characteristics of the fieldbus include:
- Bi-directional – It works in Duplex mode.
- Serial-bus – Data will transmit in small packets in a sequential manner.
- Multiple Topologies – Fieldbus works on network structures such as daisy-chain, star, ring, branch, and tree topologies.
- Fieldbus protocols are designed to distribute control functions across the automation network
- Fieldbus also have a master-slave or client-server communication model.
Fieldbus -Level
5 Levels of Fieldbus
Field Level: The field level is also called sensor bus level and it is the lowest level in a fieldbus system and includes the actual physical field devices, such as sensors, actuators, motors, and valves.
Link Level: The link level is responsible for managing the physical communication between field devices and higher-level devices.
Device Level: it’s AKA Device Bus network and it includes intelligent devices such as remote terminal units (RTUs), programmable logic controllers (PLCs), and distributed control systems (DCSs).
Control Level: It’s also known as Control Bus network. It is responsible for higher-level control functions, such as supervisory control and coordination of multiple devices and processes. This level typically comprises supervisory control systems, such as SCADA (Supervisory Control and Data Acquisition) or DCS (Distributed Control System).
Enterprise Level or Infor Level: It is the highest level in a fieldbus system and encompasses business systems, databases, and other management systems. This level includes functions related to data storage, reporting, analysis, and decision-making based on the information collected from the lower levels.
4. Profibus
- PROFIBUS stands for Process Field Bus Profibus and it is a smart fieldbus technology. It is specifically designed for high-speed serial I/O in factory and building automation applications.
- Profibus is an open-standard fieldbus defined by German DIN 19245 Parts 1 & 2.
- Profibus can support addresses from 0-127, only 0-125 are used, because 126-127 have special uses and are not assigned to operational devices.
- It also follows the Master/Slave design
- There are three types of Profibus: Fieldbus Message Specification (FMS), Profibus DP (Distributed Peripherals), an
d Profibus PA (Process Automation). - FMS is used for general data acquisition systems. DP is used when fast communications are needed to operate sensors and actuators via a centralized controller. Profibus PA is used in areas when basically safe devices and safe communications are needed.
5. OPC ( OLE for Process Control)
It is used to connect Industrial Automated devices and System to a Software devices. It is works in client/server model, where clients (such as HMI/SCADA software) send requests to servers for data for processing.
6. BACnet(Building Automation and Control Network)
It is helps to Communicate between building automation system and devices used in buildings like HVAC, Lighting, AC, Surveillance, Alarms and other utilities used in Building management. It is works as Server / Client mode, where client like Automation Software initiate request to server (Building automated hardware) for data / control operation,
For Part-1, please visit on https://techblog.kbrosistechnologies.com/guide-3-operational-technology-ot/
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FAQ
Q: What is OT?
A: OT stands for Operational Technology. IT is hardware and software that detects or causes a change, through the direct monitoring and/or control of industrial equipment, assets, processes and events.
Q: What is the difference between OT and IT?
A: OT is more about control and automation of physical systems and devices in factory environment, while IT is more focused on the management and storage of digital data.
Q: What are some examples of OT systems?
A: Examples of OT systems include industrial control systems, building automation systems, and energy management systems.
Q: What are OT protocols?
A: OT protocols are used in industrial control systems to enable devices and systems to exchange data and commands.
Q: What are some common OT protocols?
A: Some OT protocols include Modbus, DNP3, OPC, BACnet, and PROFIBUS.
Q: What are some challenges associated with OT security?
A: Security Risk
- Limited Knowledge and Experts
- Limited and Costly Training
- Lack of OEM and Legacy system which cause issue to Integrate with other system.
- Machine can start mis-behaving if anybody give wrong command or any system fails and it will impact production and might injure the people as well.
Q: What is the future of OT?
A: With the rise of Industry 4.0 and the Industrial Internet of Things (IIoT), there is a growing need for OT systems that can efficiently collect, analyse, and share data.
