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Modbus TCP/RS485

  • Requirements to connect a ModbusTCP/RS485 equipment to the Tower/Bridge

     

    This article is about the requirements to connect a ModbusTCP/RS485 equipment to the Tower/Bridge.

     

    Modbus IP RTU
    Slave address* of all equipment If applicable R
    IP address of all equipment R N/A
    Modbus register list* (so-called exchange table) of all equipment R R
    Modbus UDP ports R N/A
    Network communication configuration (Baud rate/Parity/Data bit/Stop bit) N/A R
    R = Required/O = Optional / N/A = Not Applicable

     

    Here is the parameters that you'll need to fill in order to create your modbus Equipment :

    Modbus IP :

    In an IP network you'll have to be aware of your IP parameters :
     
    Be sure that your choosen IP address is available and free on your IP network.
    Be sure that the Box can access the targeted equipment (Both are in the same subnetwork or accessible using a gateway for example)
     
     

     

    PointDexclamationSmall.png If you have a VPN on this network be sure that the Tower/Bridge is whitelisted otherwise the VPN will block Tower/Bridge communication.
     

    Modbus RS485 :

    In a serial network be sure that the chosen address (slaveID) is free and available on the network.
    Be sure that you are using a twisted paired communication cable.
    PointDexclamationSmall.png Please find here the hardware information

     

     

    Modbus properties requirements :

    In order to get your data correctly, you'll have to know the Modbus register table of the device.
    In this document (provide usually by the manufacturer) you'll have the information to fill these following blanks.
     
     

    • Slave address in Modbus IP is not mandatory. There are some Modbus TCP/IP <==> Modbus RTU gateway that forward Modbus packet to a slave. That’s why the slave address needs to be known. 

    • A list of the point to be read can be provided instead of the entire Modbus register list and the following points are required

      • Name of the variable
      • Register address
      • Data format
      • Access type
      • Modbus function used

    If you have any problem, please do not hesitate to contact us: Wattsense Support

     

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  • Checklist to debug your ModbusIP Network
    This article describes the checklist to debug your ModbusIP Network.
    Here is the important checklist to follow if you have trouble to connect modbus equipment :
     

    HARDWARE CHECK :

    1. Check that the ethernet cable is correctly plug at both side (Box and equipment).
    2. Check that the box is correctly power with a 24V DC +/-10%, 2A power supply.
    3. Led statuts : Heartbeat blinking and if the GSM is use that the led is blinking.

    NETWORK CHECK :

    1. Be sure that the box is in the same network as your equipment.
    2. Be sure that there is no firewall blocking the Tower/Bridge traffic.
    3. Check the IP network parameters if there is no DHCP server.
      1. Gateway IP address
      2. Netmask
    4. Try to ping the Modbus equipment with a laptop if possible.

    CONFIGURATION CHECK :

    1. Check the slave address of the equipment.
    2. Check if the register table is correctly matching the properties configuration in the user console.
    3. Check if you are using the correct modbus function for read and write.
    4. If you are getting wrong data please try to modify the Data format 

     

    TEST WITH AN OTHER MODBUS CLIENT (MODBUS DOCTOR) :

    1. If you cannot access the equipment with your Wattsense product, try with an other Modbus client.

     

    PointDexclamationSmall.png Aim of this test: Be sure that your modbus equipment is available and correctly configured in the modbus network. Check also if an other device (your laptop) can connect to it if the box cannot.
    If you can connect to the equipment after this test :
    - The targetted modbus equipment is accessible in the modbus network.
    - The issue would be:
    •            The Box network is not correctly setup
    •           The Box has an issue. Please contact us : support.wattsense.com

     

    First of all you will need to download the Software: Modbus Doctor
     
    Once it's done, check that you can ping the Modbus Equipment with your Laptop :
      NO PING : You need to check again your network settings

      PING : You can go ahead

     
    -> Launch Modbus Doctor
    1. Click on the "Settings" tab and setup the IP address of the targeted Modbus device.
    2. Be sure that the port is the same of the equipment (most of the time it's 502)
    3. Close the tab
    mceclip0.png
     
    1. Configure the Slave ID number of the targeted equipment. You will find it in the equipment configuration itself.
    2. Click on the "Connection" Button
         -> If you have the "Status: Connected" that means your network setup is OK.
         -> If not you should double check the modbus configuration.
    3. In order to read the properties you can setup the Register
    4. Click on READING.
    mceclip2.png
     
    If you cannot connect to the equipment also that means either:
    1. Your equipment is in default.
    2. Your network setup is wrong.
    If you can connect to the equipment correctly with your laptop that means the Box should be able to.
    ​
    If you have any problem, please do not hesitate to contact us: Wattsense Support
     
     
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