Simply put, wireless instrumentation networks can be installed at a significantly reduced cost and are quicker to deploy.
Wireless products and solutions for process automation nowadays offer flexibility and scalability at a cost which is a fraction of the equivalent wired ones. The costs savings related to infrastructure equipment, engineering, drawings, installation, commissioning, documentation and maintenance related to the investment in wireless system outweigh the investment in wired systems. In addition, the use of wireless instruments has led to new applications in the field of wireless process automation which in the past were subjected to economical, physical and technological barriers.
Very…The security methods used by the standardized protocols, such as, WirelessHART include: authentication which specifies which devices are allowed to join the network, 128-bit AES-based encryption of data, and integrity checking which establishes that messages have not been tampered with.
The security managers are an integral part of the overall wireless system design and are software components that manage secure operation of the network by controlling access and deploying security keys, data encryption and integrity checking and device security.
Very…..Industrial wireless instrumentation protocols, such as, WirelessHART and ISA100.11a have been designed ground-up taking this requirement into consideration. Reliability has been addressed in these protocols by simultaneously utilizing time, frequency and spatial diversity techniques. For instance, testing has proven that in a correctly installed WirelessHART network, data reliability (i.e. data reaches destination) is almost 99.999 %. The simple rules to follow are
• Each device must have at least 3 neighbors
• 20 % of the devices must be connected directly to the gateway
Practically there are two topologies to choose from: star and multi-hop mesh. The star topology is suitable for small scale installations where the nodes are relatively in close distance and in line of sight to the gateway. The mesh topology is used for medium to large installations and allows the communication of the nodes to the gateway even if there is not direct line of sight. This is possible as each node in the mesh can relay data to the neighbor nodes. Thus, if a node is far away from the gateway its broadcasted signal can reach the gateway through the intermediate nodes and vise-versa. Each node in WirelessHART network has the potential to operate as a router.
In short, even if the communication between two neighbor nodes is limited in range but nonetheless the use of multi-hop network enables the network designer to extend the reach of the plant network.
Many industrial wireless technologies use the 2.4GHz ISM band which is generally available globally. However, it is important to understand that the availability of channels and transmission power may vary between countries.
To ensure coexistence amongst the co-located WirelessHART and Wi-Fi networks, which operate over the same frequency band, certain bands can be blacklisted to avoid application degradation. In short, interference can lead to an overall decrease in network throughput, and can compromise QoS of a network application. However, collectively the use of adaptive frequency hopping, transmission power control and whitelist of active channels can improve coexistence and can lead to an effective radio resource management.
Easy…much easier than wired. Scalability is one of the features of wireless technology. As soon as the new instrument is physically placed where is needed it is ready for operation. A minor configuration is needed at the gateway (such as the need to input the network and join key) and start the join procedure to “identify” the new instrument and that’s it.
Traditional single-sink wireless networks have limited scalability whereas; multi-sink wireless networks can reach high levels of scalability.
The battery life depends on the energy consumption needs of the instrument. Typically the wireless instruments are expected to last many years in the field. The challenge here is to keep the battery consumption to minimum in order to increase network lifetime. In industrial applications, the sensing and communication are both high power consumers. Industrial sensors tend to have higher power consumption as compared to non-industrial sensors. Furthermore, power consumption is linked to sensors and their utilization, the device type and the communication protocol it utilizes.
In industrial wireless protocols aimed at wireless process automation, features such as smart publishing, use of deep sleep modes and time synchronized communication are adopted to reduce the onboard battery drain. Furthermore, energy harvesting techniques are being deployed to address the issue linked to the node lifetime.
The breakthrough of energy harvesting:
ABB’s WiTemp with energy harvester is the first of its kind product which has a fully integrated thermal energy harvester. Utilizing the temperature gradient between the process and the ambient atmosphere, the device can be fully powered by the harvester thereby using the battery as a backup. Get in touch with us to see the full power of the harvester.
Submit your inquiry and we will contact you