This guide provides instructions for accessing Modbus RTU (RS485) devices plugged into a VeeaHub serial connector from a Modbus TCP client. We will be using the Tridium Niagara solution as an example Router TCP client.
Note that a Modbus RTU network can be connected to any VeeaHub serial port (Mesh Edge Node or Mesh Node).
1. Hardware installation
A Modbus RTU network can be connected to any VeeaHub serial port (MEN or MN).
2. Package Deployment
2.1 In the 
Veea Control Center, select the Mesh you want to deploy the solution on.
2.2 Select “Add a Subscription.”
Then select Add a Subscription and look for the package named Bacnet/Modbus Serial <-> IP router.
At package deployment, some information is required.
2.3 Enter the following information:
- FileBrowser is the web service that will allow access to the Modbus router configuration after package deployment. (There will be one on each VeeaHub of the mesh.) For security reasons, you can choose the login credentials.
- “Serial Mode” is either “BACnet” or “router,” depending upon the kind of devices you want to connect to. In this case, “Modbus” is used as an example.
- “Serial Baudrate” is used to select the baud rate you need for your serial devices (9600, 14400, 19200, 38400, 57600, 115200).
- “BACnet MSTP” default information is not necessary for Modbus configuration.
3. Modbus RTU configuration
Once the package is been deployed on your mesh, if you need to change the default configuration or enable the router on an MN VeeaHub, you can access the FileBrowser interface.
Each router on each hub has its own FileBrowser and a change through this interface will only affect that specific hub.
To access the FileBrowser interface of the specific hub:
3.1 Go to Control Center.
3.2 Select the mesh your hub is in.
3.3 Click on the “Service” link of your hub.
3.4 Click on the “File Browser Serial” link to access remotely the Serial configuration for this hub.
This will redirect you to the FileBrowser page.
3.5 Then enter the credentials you defined at package deployment.
3.6 Double-click on the file to edit it.
3.7 Once the modification done, click on Save (icon at the top right on the screen). The service will be automatically restarted with the new settings.
4. Accessing the Modbus RTU device
Once the configuration is done, you can add Modbus RTU devices from your Modbus TCP client.
For this you need the following information:
-
the RTU device ID and the Coils/Registers Addresses
Caution: Coils/Registers Addresses must start at 40000
So, device register 18 will be reachable at 40028 -
the hub modbus router IP: <hub-SerialNumber>-serial.service.veeamesh.local
-
the hub modbus router Port: 5502
4.1 Create each device manually by clicking “New” in the “RouterABCNetwork” driver section.
4.2 Add coils/registers to read/write to this device by clicking on the point icon of the device.
This redirects you to the list of coil/registers database for this device.
4.3 You can add new entries by clicking on “New” and providing the coil/register information.
4.4 Click on OK, and it will show you the full configuration that has been created.
This will show you the values from the device.