Do you know what is wirelessHART? In automation industries and manufacturing plants, there is a constant requirement of accessing data from every process to control and regulate the processes effectively. So, to access the data, wires are used to form a connection between sensors and central control applications. HART is one of the most popular hybrid protocols being used in automation industries. HART (Highway Addressable Remote Transducer) protocol allows digital signals from sensors to overlay analog signals and then transmit information to central management software.
As the HART technology employs wires to transmit data, it becomes difficult for industries to halt their operation, in case of rewiring or sudden fault in any line. To overcome these problems associated with the HART protocol, WirelessHART protocol has been developed by HART Communication Foundation. WirelessHART can be seen as an upgraded version of the HART protocol with several advantages over HART.
So, let’s deep dive into the WirelessHART protocol and understand what it is, where it is used and how it works.
What is WirelessHART
WirelessHART is a network of spatially dispersed and dedicated wireless sensors for monitoring and recording the data from ongoing industrial processes and organizing data at a central database. It operates in the 2.4 GHz ISM band (reserved for industrial, scientific, and medical purposes) and uses IEEE 802.15.4 as a physical and media access layer.
It is license-free and used worldwide as a transfer medium for several wireless technologies like Bluetooth, Zigbee and WLAN. It is based on TSMP (Time Synchronized Mesh Protocol) technology. It means all the sensor devices stay synchronized to each other and send data in time slots.
WirelessHART protocol consists of four main elements – Wireless field devices (radio stations), Gateways, Network manager, and the Host application.
Wireless field devices are connected to a process or plant equipment. All devices are then connected to a Host application through Gateways. The network manager is used for scheduling communications between devices, managing message routes, and configuring the network.
How it works
WirelessHART employs a Flat Mesh Network Topology. In this topology, all field devices form a network and act as a signal source and a repeater simultaneously. A field device or original transmitter sends a signal to its nearest neighbor, which passes the message to the next sensor and this pattern goes on until the message reaches the actual receiver or base station.
Some alternative routes are also provided so that messages can be transferred to an alternative route in case of some obstacle or defective receiver in the original path. So, to increase the reliability of a flat mesh network, some redundant connection routes are also provided.
WirelessHART also makes use of TDMA (Time Division Multiple Access), which synchronizes the field devices in 10ms timeframes. Each device acts as an original transmitter only for 10ms and then goes to sleep or acts as a repeater. This ensures a very reliable, collision-free mesh network. As it also reduces the active time of a field device, hence help in saving power.
WirelessHART makes use of all 15 channels as defined in IEEE802.15.4, all channels are connected in parallel. WirelessHART uses FHSS (Frequency Hopping Spread Spectrum) to avoid jamming of signals from field devices. In FHSS, all channels that are already in use are blacked out to avoid collisions with signals from other devices.
This combination of 10ms timeframes synchronization and 15 channels gives WirelessHART protocol the ability to send 1500 messages or signals per second.
Where it is used
It is mainly used in manufacturing industries, factories and automation plants. It helps in reaching every part of the plant to access information, which is not safe for manual checking or hazardous for humans. It is gaining wide acceptance in real time process industries. It is being regarded as a paradigm shifter in automation industries.
Some of the applications for which it is used in industries are-
- Ensuring safety by portable gas monitoring,
- Measurement of mobile batch processes,
- Remote areas in petroleum and construction industries,
- Monitoring of mechanical and electrical devices like the pump, motor, etc.
Advantages
WirelessHART has several advantages over its predecessor HART technology. It has better security, reliability and at the same time simpler to use.
Security: It is more secure as it has 128-bit AES encryption. It provides a unique encryption key for each message. As WirelessHART does not use TCP/IP protocol, it is safe from traditional hacker attacks.
Reliability: In industries, working conditions, external noise, and electromagnetic interference pose a significant challenge to the uninterrupted transmission of signals. FHSS ensures the continuous transmission of information without any collision or interference. The time synchronization technique helps in getting signals from each field device with less power consumption.
Simple: It is very simple to implement in an industry environment, with the added advantage of being compatible with existing HART devices and systems. Removal of wires makes it easy to maintain in case of a change in plant infrastructure.
Conclusion:
It can now be concluded that WirelessHART technology is going to make a positive change in various automation and manufacturing industries. Though, the success of this technology will mainly depend on the adoption of it by industries from various sectors. This is all for this blog post, see you later in the next blog.
Hope you all understand what is WirelessHART? For any doubt let us comment below we would love to answer you to stay connected with TechAwarness for more interesting articles. This article has been written by Sachin Singh. You can follow him on Twitter and Linkedin.
