May 2, 2019

Solar PV Monitoring Based on LoRa Topology

RF MESH VS POINT TO MULTI-POINT TOPOLOGY

Network topology is the arrangement of devices in wireless network to establish communication among them. It defines a layout of a network that means it regulates how different nodes are connected and transferring data together within a network.

There are numerous types of IoT topologies for networking, the most common being mesh topology,and point-to-Multi point topology. All networks have its own  advantages and disadvantages

When it comes in Solar plant deployment, Network selection purely depends on infrastructure of the plant as well as the type of SCADA solution which has been provided. Typically factors like distance, bandwidth line of sight obstacles is also defining the architecture selection

RF Point to Multi Point Network –(P2MP)

As the name suggests,Point-to-multi-point (P2MP) architecture refers to communication that is accomplished through a distinct and specific form of one-to-many connections.This network tends to be easier to deploy and the more cost effective.

Point to multi-point  consist of two parts. A base station and group of Nodes. The base station can communicate with many nodes however the subscriber can only talk to one node and that being the base station.

PTMP Advantages

  • complexity in the network is driven to a central Unit
  • Cost effective
  • Efficient means of sharing capacity
  • Complete access of entire network from one location.
  • Easy up-gradation of the system
  • Easy maintenance and monitoring

PTMP Disadvantages:

  • Line of Sight (LOS) is challenging
  • Failure at central device leads to entire system failure
  • Alternate system needs to be deployed to prevent the data loss in case of the central unit failure

RF-Mesh Network

A mesh topology is a network topology in which all the network nodes are individually connected to most of the other nodes where there is no concept of a central switch, hub or gateway which acts as a central point of communication to pass on the messages. Packets jump(hop) from one node to the other until it reaches the destination. This includes the self-configuring, self-healing nature and the built-in redundancy/reliability of the multi-hop environment.

In mesh all the nodes communicate directly without the need of central device (Hub). It can also refer as PTP or Point to Point configuration. A mesh topology can be a full mesh topology or a partially connected mesh topology.

A fully connected mesh topology has all the nodes connected to every other node.

On the other hand, a partially connected mesh topology does not have all the nodes connected to each other.

Mesh networks when deployed correctly can be more dependable and provide better coverage with line of sight obstacles

Mesh Advantages(PROS):

  • Self-healing - the network finds the fastest and most reliable paths to send data if nodes are blocked or lose their signal.
  • Manages high amounts of traffic, because multiple devices can transmit data simultaneously
  • A failure of one device does not cause a break in the network or transmission of data.
  • Adding additional devices does not disrupt data transmission between other devices.
  • Mesh networks provide better coverage with line of sight obstacles.

Mesh Disadvantages(CONS)

  • Complex to maintain and monitor and central access is not available.
  • Higher network latency due to multiple hops from the sensor to the gateway.
  • The cost to implement is higher than other network topologies, making it a less desirable option. Building and maintaining the topology is difficult and time consuming. The chance of redundant connections is high, which adds to the high costs and potential for reduced efficiency.

EagleSun Scada deploys LoRa based  broadcasting technology (P2MP) that acquires solar plant data robustly without network latency, which is the most desirable feature of any IoT based wireless remote monitoring system. Mesh sounds great theoretically,but it causes the complexity of the system significantly
The benefits of the PTMP far outweigh the risks of Mesh. P2MP topology will benefit you to take the time in the design phase and architect a “predictable path wireless system. To summarize, EagleSun SCADA, an IoT enabled solar plant data monitoring and controlling system which is more reliable and more cost effective.

AUTHOR
Arun Ashok
Software Engineer
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