Mesh network deployment | Treon Knowledgebase

Deployment of the Wirepas mesh network for Assets

Mon, 01 Jan 0001 00:00:00 +0000

Introduction

Before deploying a Wirepas mesh network, it is important to learn about key principles of Wirepas mesh networks and solutions to common issues.

When a Treon solution is deployed, it is key to plan the Wirepas mesh network before the actual on-site installation. While the layout of the deployment environment often defines where the individual sensor nodes need to be placed, it is essential to plan the whole mesh network layout before the deployment, so all data is delivered from the sensor nodes to the backend smoothly.

Information Required:

Layout of the deployment area
Intended placement of Treon Industrial Node X sensors
Connection type of Treon Gateway(s) (ethernet, wi-fi, cellular connection) and restrictions of these within the deployment area
Type of collected data (scalar, FFT or raw data)

Mesh Network Basics 

Treon products work on basis of a Wirepas mesh network. This network will establish itself once the Treon Gateway and the Treon Industrial Node X sensors have been activated and it will form the most efficient connection layout.

Fig.: Treon products are based on sensor nodes that deliver data to a Treon Gateway via a

Wirepas mesh network. The gateway transfers the data to the backend.

Key principles of the Wirepas mesh network 

Treon sensor nodes communicate via Wirepas, a low power network mesh technology. 
In a mesh network, individual nodes transmit their own measurement data and also act as routing nodes, transmitting the data of other nodes. Relaying nodes in a mesh provide the most efficient communication path from all nodes to the gateway and back.  
The mesh network does not have one steady configuration. Instead the way information is routed from nodes to the gateway and back can change as the mesh network continues to keep the ideal mesh network layout. In case you have more than one Treon Gateway in your mesh network, also the gateway an individual node is transferring data to via intermediate nodes may change.
All devices within the Wirepas network arranges themselves into the optimal possible configuration of data routing, based on the signal strength between nodes. 
If a device fails or communication is blocked for any other reason, the mesh will automatically re-arrange itself and use alternative routes to communicate with the Treon Gateway and nodes. 
The Treon Gateway can connect to maximum 14 nodes directly and up to several dozen via mesh network.
All nodes in the mesh network will transfer data. Sensor nodes collect data themselves and forward data for other nodes. Routing nodes are not collecting data and are placed to enhance the mesh network layout and bypass structural obstacles.

Placement of Devices & Optimal Layout 

Optimal Order of Deployment 

When you look at the layout of the deployment area, the first information you have are the locations of the sensor nodes. They need to be installed in the places where they need to collect data. From this starting point you can plan where the Treon Gateways and possible routing nodes need to be placed.

For the best performance, place the gateway in a way that as many sensor devices as possible are directly in its range. The Treon Gateway supports connection to up to 14 nodes directly. This way, the nodes closest to the gateway will not become congested with routed data, and the network can automatically optimize data routes. The ideal layout of a mesh network is an actual mesh.

Fig: A mesh layout is the optimal layout for the mesh network

Range of Treon Industrial Node X sensors

The maximum distance between the Treon Gateway and the Treon Industrial Node X sensors, and in-between sensor nodes, can vary from a few tens of meters to up to 60 meters, depending on the individual deployment environment. A clear line of sight between devices will help a longer distance and optimal conditions for radio transmission.

Specifically in an industrial environment with metal structures and walls, the conditions for radio transmission might not be optimal and the range can be limited to a few tens of meters. In this article we offer strategies on how to work also in a industrial and other complex environments, how to bypass structures and create a well-designed mesh network in any kind of environment! 

Short Routes

The data from each individual node should be able to travel to the gateway in the shortest possible way.

Fig: The data from node 4 sensor nodes pass through a routing chain, which can lead to data congestion and high battery drainage.

Fig.: The longer the routing chain, the more data is transferred through nodes higher up in the chain.

Gateway to sensor node Ratio 

When designing the mesh layout, it is important to consider the amount and the location of the Treon Gateways in the deployment area.   

The Treon Gateway can connect up to 14 nodes directly, and up to tens of devices via the mesh network. Depending on the data amount transmitted from the nodes to the gateway, we recommend deploying a second gateway at the latest when more than 50 nodes are connected. This will make sure that all your data is flowing from the nodes to your backend without interruption. 

Please note that it is a key aspect of designing the mesh network to avoid long routing pathways in your layout. Individual nodes that transmit the data for multiple other nodes can cause problems. A large amount of data can congest the network traffic, and you might not receive all the data from all sensor nodes in the expected timeframe, or not at all. Transmitting data for several other nodes also needs more power and will lead to a lower battery life expectancy for the routing node. If the planned layout seems likely to create such ‘super-routing nodes’ in the mesh network, please consider adding another Treon Gateway instead. 

Fig.: In this mesh network, a few nodes have to transmit all data for a high number of sensor nodes.

Fig.: By adding a second gateway to the mesh network, the number of routing nodes is reduced.

Gap Bridging

If the gateway and sensor nodes are too far apart for efficient data transmission, place one or several routing nodes between them to transmit data from one node to another. Avoid layouts where one node routes the traffic from several other nodes. This may happen if a group of sensor nodes is too far from the gateway or placed in a long line. Optimally, the sensor nodes should have multiple routes for sending their data to the gateway, meaning each sensor nodes should be in reach of several other nodes.  

Please note that if you add more nodes or gateways to your mesh network later, the entire mesh will reorganise itself. This process may take a few hours. However, the nodes continue to operate at the same time. 

Routing nodes are nodes that are set up to not collect measurements and to only route data from other nodes and need a specific configuration from Treon.

Bridging gaps with long single chains of routing nodes, even when transmitting the data from only one sensor node, should be avoided when deploying an additional Treon Gateway close to the sensor node is an option.

Fig.: A node is too far away from the next and cannot connect.

Fig.: A routing node creates a bridge for this gap.

While bridging long distances between individual nodes in a mesh network, it can also help bypass structural issues that keep nodes from communicating. Thick walls and large metal objects might block the signal and can be circumvented by installing an additional node to act as a forwarding device and connect devices behind the obstacle to the mesh network.

Fig.: A node cannot connect to the mesh network due to a structural issue.

Fig.: A routing node helps bypass the structural issue. 

When planning your mesh network, it is not always clear that you need gap bridging nodes. Depending on the individual three dimensional layout in the deployment area, and depending on surface and core materials of structures, a signal might be bounced farther than expected or blocked closer to another node than anticipated. Often only the on-site deployment will show that a node cannot connect. Always be prepared to place additional Treon Gateways and routing nodes if that happens. 

Impact of routing large data on mesh network performance

An important factor when designing the layout for a mesh network is the amount of data that will be transmitted through the mesh network to the Treon Gateway.

In general, we distinguish between:

Scalar data: few data fragments create little traffic in the mesh network.
Burst data: FFT and specifically raw data create thousands of data fragments that might potentially cause issues in the mesh network.

If you want to route burst data, please consider:  

The more sensor measurements are triggered at the same time, the more traffic will be through the mesh network. Triggering measurements and sending raw data at different times can help solve this.

If the data from several sensor nodes has to pass through a single node, it is more likely that data congestion will occur, and measurement data can be lost. Routes through the mesh network should be short, and enough end points in the form of Treon Gateways are essential.

Impact of routing data on battery life 

Next to basic operation and sensor measurements, transmitting data has a high impact on the Treon Industrial Node X sensor’s power consumption.

While transmitting scalar data has much less impact on battery lifetime as fewer data fragments need to reach the gateway, transmitting FFT and specifically raw data can create issues when the data of several sensors is routed via an individual node.

Activating the Mesh Network

Mon, 01 Jan 0001 00:00:00 +0000

Introduction

Before and after the deployment of a Wirepas mesh network, it is important to test and troubleshoot common issues in deployment.

Testing the network

Before you install the Treon products at the deployment site, first perform a dry-run of the system to test if the network functions properly. As the deployment environment often is in an industrial setting, troubleshooting off-site will be easier.

Additionally, in case the network does not perform as expected after on-site deployment, the troubleshooting will be much easier as you can rule out factors that previously have been working.

Requirements

All Treon Industrial Node X sensors and Treon Gateways have to be turned on.
The Treon Gateways have power and are set up with a network connection. (Wait 5 minutes for ethernet and Wi-Fi connections and 10 min for cellular connections after turning on.)
Access to the Treon Connect instance.

Testing Goals

All Treon Industrial Node X sensors are connected (Treon Industrial Node X: shortly press the button, the node should blink green two times.).
The Treon Connect instance receives sensor data from the Treon Industrial Node X sensors
There are no errors reported.

On-site deployment performance

 After you have done the physical installation of all sensor nodes and Treon Gateways, it is time to test how it performs in practice.

Requirements:

All Treon Industrial Node X sensors and Treon Gateways have been installed and activated in the deployment area.
The Treon Gateways have power and are set up with a network connection. (Wait 5 minutes for ethernet and Wi-Fi connections and 10 min for cellular connections after turning on).
The Treon Connect instance receives data from all deployed sensor nodes.
The deployment area reflects the conditions of everyday operation.

Please Note: In case you have a mesh network with multiple Treon Gateways, always first power them on before the Treon Industrial Node X sensors and wait until the light is green. Then you can activate all the nodes. This way, the sensor nodes do not all form a mesh network focused on the first gateway before the second gateway is online, but immediately arrange themselves into the optimal mesh layout.

Testing Goals

Is the backend receiving data from the sensor nodes?
Is any data missing or arriving late? (Please note that raw data might take up to 10 minutes to arrive in the backend.)
How is the network connection strength of the Treon Gateway (using SIM or Wi-Fi connection)?
Mesh network telemetry - how strong is the link quality between the nodes?
Access point mode: can check sim and wi-fi connection strength?

Stress Test

It is always advisable to test if the mesh network is functioning and data from all sensor nodes is delivered to the Treon Gateway without issues. You can perform a stress test without waiting for the measurement intervals set in the sensor nodes' configuration by triggering an additional measurement, and therefore data routing through the mesh network, for all sensor nodes in the mesh network.

Specifically, if you want to use raw data of your sensor nodes, it is essential to perform a stress test and see if any data is lost or arrives late if you trigger all sensors at the same time. The result will allow to correct any issues in the mesh layout, for example by adding additional Treon Gateways, or by staggering the sensor trigger times so they deliver their data at different times through the mesh network, avoiding data congestion.

Mesh network telemetry

You can analyse your mesh network structure online in your Treon Connect instance.

Node Telemetry

The Networks app in your Treon Connect instance analyses and visualises the telemetry data of nodes within the mesh network.

Issues such as low connection quality between individual nodes, long routing chains that may lead to increased power consumption, or message buffers maxing out on select nodes can easily be identified.

Fig.: Treon Connect Networks visualises the mesh structure.

On mouse-over the data of any of the devices in the mesh network is displayed:

Fig.: Treon Connect Networks visualises the mesh structure.

Symptoms of Suboptimal Mesh Network Performance

No data is shown in Treon Connect, even though all nodes are activated, and the Treon Gateway is powered on and has network connection.

Please check that all Treon Industrial Nodes have been activated and have a green light, indicating that they are connected to a sink in a Treon Gateway.

Nodes status light is not green, which means the node is not connected to a sink.  

If the Treon Industrial Node shows no status light at all, it either is not powered on yet or it has run out of battery power.

If the Treon Industrial Node shows a red light (press the button, first a green light shows, the second light gives connection status: red = not connected, green = connected), it has no connection to another node, or there is another break in the connection in the mesh network between this node and the gateway.

Check all nodes to see if more have the same issue and if there is a break in the connection chain. Make sure all nodes are in connecting distance to each other and that there are no major obstructions to the network signal in-between the nodes.

Only some part of the data from one or several sensor nodes is shown in Treon Connect.

Messages only arrive sporadically, which means they were buffered and transmitted late.
This is most likely to happen with FFT and raw data, when individual nodes have to forward the measurement data from several other nodes. The sensor data might overload the buffer of the node and data is lost. Make sure that there are enough alternative routes in the mesh network and think about installing more Treon Gateways in different areas in order to keep transmission pathways short.

Data from one or several individual sensor nodes does not show in Treon Connect.

If the deployment works well in general, but one or several sensor nodes do not deliver any data, double-check that the nodes are activated, have connection to the gateway. Further check that messages from the nodes arrive at the gateway, and that the backend connection is set up correctly.

Root Causes of Suboptimal Network Behaviour 

The symptoms of a suboptimal mesh deployment are not always that clear. It can be that the setup is working but feels slow, that only occasionally some data is lost, or that individual nodes do not always react to commands.

Please take the following factors into account when re-evaluating your mesh network deployment:

Distances and Obstacles In an optimal setting the distance between nodes and from nodes to the gateway can be from 10 up to 60 meters. Specifically, when deploying in industrial environments, obstacles such as wall, large machines and other radio signal reflecting or obstructing structures are common. Radio signals can be hard to predict in a complex environment. Sometimes distant nodes can have an unexpected high signal strength when surfaces are reflecting the radio signal just right. Sometimes a close node has a low signal strength when the radio signal is blocked by small obstacles that are just in the wrong locations.

Try to identify the nodes that have a weak radio signal and analyse the three-dimensional space to identify potential obstacles. In some cases, obstacles can be moved or changed, and often gap bridging with an additional node helps to bypass the structural problem. In case the layout has several clusters of sensor nodes, or a small amount of more distant nodes, it can be a good solution to install additional gateways in their immediate proximity.

Also take into account that heavy traffic disturbances such as many people, moving goods, forklift traffic, animals, etc. in the deployment environment will have an influence on radio signals. When planning your deployment, take into account how the space is used when it is fully operative.

Mesh routing alternatives
The optimal layout of a Wirepas mesh network is, quite literally, a mesh configuration. Every node in the mesh is ideally connected to several other nodes, and as many nodes as possible are connected directly to the gateway. This means that there are alternatives to mesh configuration that allow data to flow freely from the nodes to the sink in the gateway.

Analyse the layout of your mesh network to see if there are enough routing alternatives. Additional nodes and gateways can help improve the layout of the network.

Routing Chains
While the best network configuration is a mesh layout, the worst would be one long routing chain. In this layout, the data from all sensor nodes is sent along a chain of nodes. The closer the node is to the gateway, the more data it has to transfer from the nodes further down in the routing chain. This can lead to late and to lost data packages when buffer peaking occurs.

Especially when working with burst data this quickly becomes a problem as the amount of data fragments is much higher. Additionally, the more data a node has to transfer, the quicker the battery gets drained.

If you can identify routing chains in your mesh network, see if you can diffuse them via additional nodes or an additional gateway placed close to the routing chain, therefore connecting directly to the sensors in the routing chain.

Large data in a Wirepas mesh network

Mon, 01 Jan 0001 00:00:00 +0000

Introduction

Working with large amounts of data, that occur when transmitting burst data from the nodes to the Treon Gateway, needs to be taken into account when planning and deploying a mesh network. While routing of scalar data is easier and has less potential to cause problems, it is possible to send raw data from your Treon Industrial Node X sensors to the Treon Gateway by planning the mesh network accordingly.

Throughput limitations

The data handling and transfer by nodes within a Wirepas mesh network is defined by several factors. Understanding the limitations of the mesh layout when it comes to large data makes it is possible to take them into account when planning the deployment.

Data type

What kind of data is used has an immense influence on the amount of data transmitted from the measurement node to the gateway through the mesh network.

Scalar data means that one message fragment contains a single measurement.

KPI measurements = 6 message fragments (a measurement on 3 axes with 2 values each = 6 messages)

Burst data means that the data from one measurement is split into several fragments and then reassembled by the backend solution.

FFT data= 600 messages per measurement Raw data = 1666 messages per measurement

Please note: All values given are valid for standard product settings!

Buffer capacity

Each Treon Industrial Node X has two dedicated data buffers.

The measurement buffer collects the sensors' own measurements until they are forwarded via the Wirepas mesh network. The buffer space for the Treon Industrial Node X is 110592 individual measurements.

Once the measurement buffer is full, the sensor node will stop any new measurement until the collected measurement data has been transmitted. This means that while the buffer is not emptied, no on-demand measurement can be triggered. If you try to trigger a new measurement while the buffer is full, you will get a message that the sensor node is occupied. Timed measurements are kept in a waiting list and are automatically postponed until the buffer is empty so the data can be stored. The next measurement after this will then be executed at the pre-scheduled time interval again.

Please note that one measurement can have varying amount of data samples, depending on the exact settings for the measurement.

Example:
A Treon Industrial Node X performs a vibration measurement every full hour (10:00, 11:00, 12:00 etc.). An OnDemand at 10:55 triggers an additional measurement at 10:55 which takes 10 minutes to transmit. The Treon Industrial Node X will execute the interval measurement at about 11:05 instead of 11:00. The next interval measure will be as scheduled at 12:00.

The routing buffer is much smaller than the measurement buffer, it’s size always depends on other activity within the mesh network at a given time. Incoming data is stored in the routing buffer until it can be routed forward within the mesh network, or directly to the gateway, depending on the exact position of the routing node within the mesh network. Usually this happens immediately.

In case a node has both its own measurement data to transmit AND is routing data from other nodes, it will attempt to perform both actions at the same time. This means that limited by the total transmitting capacity, the data from both measurements will take longer to transmit. In case a single node is transmitting raw data from several nodes, data congestion can occur.

Data congestion means that data cannot be forwarded in the mesh network as nodes closer to the gateway are transferring data too slowly or not at all. This will affect the whole connected branch of the mesh network. As a result, either individual data fragments can be lost, or even whole measurements.

Periodization of data delivery

The more data is transferred from the sensor nodes to the gateway, the more likely the data buffers in the nodes can be exceeded and data loss occurs.

Triggered data staggered: less data at the same time, less likely to cause problems.

Fig.: When a node has to forward the measurement data of several other nodes at the same time, it cannot send the data as fast as it is receiving it. As a consequence, data will be lost after stored data has exceeded this node's buffer size.

Fig.: When the sensor nodes are triggered staggered at different times, less data is forwarded through routing nodes at the same time.

Signal Strength (RSSI)

The signal strength between the nodes in the mesh network, and between the nodes and the gateway, only have an influence on data throughput in case the link quality is bad.

You can check the signal strengths in your Treon Connect instance in the Network section.

The recommended values provided by Wirepas are the following:

RSSI Limit	Description
>= -60 dBm	Excellent.
-75 dBm <RSSI <-60 dBm	Good. Recommended from here and up to ensure stability.
-80 dBm < RSSI < -75 dBm	Average. KPI’s will work fine. FFT and Raw data might experience issues on larger networks. Depending on the use case this setup can be stable enough.
-85 dBm < RSSI < - 80 dBm	Bad, unstable connection not recommended for large deployments. KPI’s will work OK, FFT and Raw data are likely to drop packages.
RSSI <= -85 dBm	No connection.