Difference between revisions of "Modbus TCP Client configuration example"

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=Summary=
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<p style="color:red">The information on this page is updated in accordance with the [https://wiki.teltonika-networks.com/view/FW_%26_SDK_Downloads'''00.07.09'''] firmware version .</p>
−
Modbus TCP Master section is used for configuring your router as a master device and other routers configured in this section as slave devices. A Modbus TCP master device can then request data from these Modbus TCP slaves.
+
__TOC__
 +
==Summary==
 +
This article contains instructions on how to configure Modbus TCP functionality on most of the Teltonika Networks devices (with the exception of TAP and TSW series)
  
−
[[File:ModbusTcpMasterSchemeTopology.png|border|class=tlt-border|center|Topology]]
+
==Configuration overview & prerequisites==
 +
Before we begin, let's take a look at the configuration that we are attempting to achieve and the prerequisites that make it possible.  
  
−
First, let’s configure our second router which will be acting as a slave device.  
+
Configuring port forwarding on Teltonika devices is a simple process that involves just a few steps and can easily be replicated across various devices. The number of devices involved will depend on the specific use case, but the setup can be scaled seamlessly. In the example below, we will use the RUTX50 as the Modbus TCP Client and RUT956 as Modbus TCP Server.
  
−
=Configure Modbus TCP slave device=
+
[[File:Networking Topology Modbus basic config.png|border|class=tlt-border|]]
−
In this example, we would be configuring our slave device to have a 192.168.1.2 internal IP address. This can be done by changing the IP address parameter on Network->WAN page:
 
  
−
[[File:ExampleModSlave1Edit.png|border|class=tlt-border|center|Slave Device WAN configuration]]
+
'''Prerequisites''':
 +
* A device from the RUT, RUTX, RUTM, RUTC or TRB series gateway;
 +
* A PC, Laptop, tablet or a smartphone
 +
* Router acting as Modbus TCP Server must have a SIM card with a Public Static or Public Dynamic IP address (more on IP address types '''[[Private and Public IP Addresses|here]]''') to make remote access possible
 +
* (Optional) If the router's SIM card has a Public Dynamic IP address, you may want to additionally configure a '''[[Dynamic DNS]]''' hostname
  
−
[[File:ExampleModSlave2Edit.png|border|class=tlt-border|center|Slave Device WAN config]]
+
{{Template:Networking_rutos_manual_basic_advanced_webui_disclaimer
 +
| series = RUTX
 +
}}
  
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Now we need to enable Modbus service for this slave device as we will open a specific port for letting through TCP communications (it is also possible to 'Allow remote access' if we wish to access this router from external WAN using its public IP). This is done on Services->Modbus page:
+
=Modbus TCP Server=
 +
Configure Modbus TCP Server device. our slave device to have a 192.168.1.2 internal IP address. This can be done by changing the IP address parameter on Network → WAN page:
  
−
[[File:ExampleModSlave3Edit.png|border|class=tlt-border|center|Slave Device Modbus Config|alt=]]
+
==Modbus TCP Server configuration==
 +
Setup router as Modbus TCP Server. It can be done in '''Services → Modbus → Modbus TCP Server '''. Once in the Modbus TCP Server configuration, find the '''Enable''' the instance and everything else can be left as default or changed based on your needs:
  
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<table class="nd-mantable">
+
[[File:Enable modbus tcp server.png|border|class=tlt-border]]
−
    <tr>
 
−
        <th>Field</th>
 
−
        <th>Value</th>
 
−
        <th>Description</th>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Enable</td>
 
−
        <td>off | on; default <b>off</b></td>
 
−
        <td>Turns Modbus TCP on or off.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Port</td>
 
−
        <td>integer [0..65535]; default: <b>502</b></td>
 
−
        <td>TCP port used for Modbus communications.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Device ID</td>
 
−
        <td>integer [0..255]; default: <b>1<b/></td>
 
−
        <td>The device's Modbus slave ID. When set to 0, it will respond to requests addressed to any ID.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Allow Remote Access</td>
 
−
        <td>off | on; default: <b>off</b></td>
 
−
        <td>Allows remote Modbus connections by adding an exception to the device's firewall on the port specified in the field above.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Keep persistent connection</td>
 
−
        <td>off | on; default: <b>off</b></td>
 
−
        <td>Allows keep the connection open after responding a Modbus TCP master request.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Connection timeout</td>
 
−
        <td>integer; default: <b>0</b></td>
 
−
        <td>Sets TCP timeout in seconds after which the connection is forcefully closed.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Enable custom register block</td>
 
−
        <td>off | on; default: <b>off</b></td>
 
−
        <td>Allows the usage of custom register block.</td>
 
−
    </tr>
 
  
 +
Once finished click '''Save & Apply''' to save the configuration.
 +
==Remote access configuration==
 +
If you wish to remotely access the Modbus TCP Server device navigate to the '''System → Administration → Access Control''' tab. Once in the '''Administration-Access Control''', find the '''Enable remote HTTP access''' field and put a check mark next to it:
  
−
</table>
+
[[File:enable remote access HTTP.png|border|class=tlt-border|]]
  
−
=Configuring Modbus TCP master device=
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'''Note:''' If you have a Public IP address already, you can skip this step.
  
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==Adding a new slave device==
+
To set the APN, while in the router's WebUI, navigate to the '''Network → Mobile → General → Interface mob1s1a1 APN configuration''':
−
On the master device (in this example master device has 192.168.1.1 internal IP address) open Services->Modbus->Modbus TCP Master. To add a new slave, first, click the add button.
 
  
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[[File:ExampleModSlave4Edit.png|border|class=tlt-border|center|Master device Modbus Slave devices menu.]]
+
[[File:Set APN PF.png|border|class=tlt-border|alt=]]
  
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Once you have clicked that button, enter the following configuration so we can add the slave device:
+
Once in the '''Interface mob1s1a1 APN configuration''' window, edit your mobile interface, find the '''APN''' field and enter you Internet Service Provider's APN:
 +
# '''Disable the Auto APN option'''
 +
# Choose the correct '''APN''', which gives out a public IP address (for more information about that contact your Internet Service Provider)
  
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[[File:ExampleModSlave5Edit.png|border|class=tlt-border|center|Master devies Add Slave Config]]
+
[[File:Set APN PF APN selected.png|border|class=tlt-border]]
  
−
<table class="nd-mantable">
+
Additional notes on APN:
−
    <tr>
+
* '''NOTE 1''': don't use the exact APN value as seen in the example above as it will not work with your SIM card. APN depends on your Internet Service Provider (ISP), therefore, your ISP should provide you with their APN or, in many case, you can find your ISP's APN with an online search.
−
        <th>Field</th>
+
* '''NOTE 2''': furthermore, it should be noted that not all SIM cards support this functionality. Static or Dynamic Public IP addresses (obtained through APN) are a paid service and setting any APN value for a SIM card that doesn't support this service will most likely result in losing your data connection. If this is the case, it can be fixed by simply deleting the APN, but it also means that remote access through mobile WAN IP will most likely not work on your SIM card.
−
        <th>Value</th>
+
* '''NOTE 3''': in some cases the SIM card doesn't require an APN in order to obtain a Public IP address. If that is the case for you, simply check what your router's mobile WAN IP address is - if it's already a Public IP address, then you don't need to set an APN. The easiest way to find what your mobile WAN IP address is to log in to the router's WebUI and check the '''MOB1S1A1''' widget in the '''Overview''' page:
−
        <th>Description</th>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Enable</td>
 
−
        <td>string; default: <b>none</b></td>
 
−
        <td>Slave device's name, used for easier management purposes.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Name</td>
 
−
        <td>off | on; default: <b>off</b></td>
 
−
        <td>Turns communication with the slave device on or off.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Slave ID</td>
 
−
        <td>integer [0..255]; default: <b>none</b></td>
 
−
        <td>Slave ID. Each slave in a network is assigned a unique identifier ranging from 1 to 255. When the master requests data from a slave, the first byte it sends is the Slave ID. When set to 0, the slave will respond to requests addressed to any ID.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>IP address</td>
 
−
        <td>ip; default: <b>none</b></td>
 
−
        <td>Slave device's IP address.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Port</td>
 
−
        <td>integer [0..65535]; default: <b>none</b></td>
 
−
        <td>Slave device's Modbus TCP port.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Period</td>
 
−
        <td>integer [1..86400]; default: <b>60</b></td>
 
−
        <td>Interval at which requests are sent to the slave device.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Timeout</td>
 
−
        <td>integer [1..30]; default: <b>5</b></td>
 
−
        <td>Maximum response wait time.</td>
 
−
    </tr>
 
  
−
</table>
+
[[File:Where public IP.png|border|class=tlt-border]]
  
−
Scroll down and click “Save and Apply”
+
=Modbus TCP Client=
  
−
[[File:Picture6.png|border|class=tlt-border|center|Save and Apply]]
+
==Modbus TCP Client configuration==
 +
On the Modbus TCP Client device open Services → Modbus → Modbus TCP Client. To create a new instance click on '''Add'''. A new pop-up window should appear:
  
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After this, this is how your main Modbus Master panel should look:
+
# '''Enable''' the '''instance'''
 +
# '''Enter''' the '''desired name'''
 +
# '''Server ID''' must match with the previously configured '''Server device ID'''
 +
# Enter the '''mobile WAN IP address of the Modbus TCP Server device'''
 +
# Chose same '''Port as in Server device - 502'''
 +
# Enter '''Period in seconds''', how often requests will be sent to the Server device
  
−
[[File:ExampleModSlave7Edit.png|border|class=tlt-border|center|Master Device Modbus Slave menu]]
+
[[File:Enable modbus tcp client config.png|border|class=tlt-border]]
−
==Testing==
 
−
For testing, if the functionality is working we can configure a request. A Modbus request is a way of obtaining data from Modbus slaves. The master sends a request to a slave specifying the function code to be performed. The slave then sends the requested data back to the Modbus master. You can create a maximum of 64 request configurations for each slave device.First, click the edit button:
 
  
−
[[File:ExampleModSlave7Edit.png|border|class=tlt-border|center|Master Device Modbus Slave menu]]
+
==Requesting Modbus data==
 +
For testing, if the functionality is working we can configure a request. A Modbus request is a way of obtaining data from Modbus Server. The Client sends a request to a Server specifying the function code to be performed. The Server then sends the requested data back to the Modbus Client.
  
−
Scroll down to the “Request configuration” section.  
+
Scroll down to the '''Request configuration''' section. Write a name for the request and click the '''Add''' button:
  
−
[[File:ExampleModSlave9Edit.png|border|class=tlt-border|center|Request Configuration]]
+
[[File:Add new request modbus tcp client.png|border|class=tlt-border]]
  
−
Write a name for the request and click the “Add” button.
+
In this case we are trying to get System temperature (in 0.1 °C) information so configure the next options:
  
−
[[File:ExampleModSlave10Edit.png|border|class=tlt-border|center|Add new request.]]
+
# '''Data type''': 32bit INT, Byte order 1,2,3,4 
 +
# '''Function''': Read holding registers (3)
 +
# '''First register''': 6
 +
# '''Number of register'''s: 2
 +
# '''Enble''' brackets if not needed
 +
# '''Enable''' the request
  
−
And enter a data type, a function, first register, number of registers, if you need brackets or don’t and enable the request. In this case we are trying to get System uptime information so configure the next options:
+
The information about correct Modbus registers usage can be found [[https://wiki.teltonika-networks.com/view/Monitoring_via_Modbus_RUTOS|'''here''']].
  
−
[[File:ExampleModSlave11Edit.png|border|class=tlt-border|center|Configuring new request]]
+
[[File:Add new request modbus tcp test.png|border|class=tlt-border]]
  
−
<table class="nd-mantable">
+
Under the '''Request Configuration''' section there will be another section called '''Request Configuration Testing''' this is where you can test that the parameters that you set work properly. Just select the request that you want to test and click the '''test button''' and you should get an output.
−
    <tr>
 
−
        <th>Field</th>
 
−
        <th>Value</th>
 
−
        <th>Description</th>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Name</td>
 
−
        <td>string; default: <b>Unnamed Parameter</b></td>
 
−
        <td>Request name. Used for easier management purposes.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Data type</td>
 
−
        <td>8bit INT | 8bit UINT | 16bit INT, high byte first | 16bit INT, low byte first | 16bit UINT, high byte first | 16bit UINT, low byte first | 32bit float, Byte order 1,2,3,4 | 32bit float, Byte order 4,3,2,1 | 32bit float, Byte order 2,1,4,3 | 32bit float, Byte order 3,4,1,2; default: <b>16bit INT, high byte first</b></td>
 
−
        <td>How read data will be stored.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Function</td>
 
−
        <td>1 | 2 | 3 | 4 | 5 | 6 | 15 | 16; default: <b>3</b></td>
 
−
        <td>A function code specifies the type of register being addressed by a Modbus request. The codes represent these functions:<br>
 
−
            <ul>
 
−
                <li><b>1</b> - read Coil Status</li>
 
−
                <li><b>2</b> - read Input Status</li>
 
−
                <li><b>3</b> - read Holding Registers</li>
 
−
                <li><b>4</b> - read Input Registers</li>
 
−
                <li><b>5</b> - force Single Coil</li>
 
−
                <li><b>6</b> - preset Single Register</li>
 
−
                <li><b>15</b> - force Multiple Coils</li>
 
−
                <li><b>16</b> - force Multiple Registers</li>
 
−
            </ul>
 
−
        </td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>First Register</td>
 
−
        <td>integer [0..65535]; default: <b>1</b></td>
 
−
        <td>First Modbus register from which data will be read.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Number of Registers</td>
 
−
        <td>integer [1..2000]; default: <b>none</b></td>
 
−
        <td>Number of Modbus registers that will be read during the request.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Enabled</td>
 
−
        <td>yes | no; default: <b>no</b></td>
 
−
        <td>Turns the request on or off.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Test</td>
 
−
        <td>- (interactive button)</td>
 
−
        <td>Generates a Modbus request according to given parameters in order to test the request configuration. You must first save the configuration before you can use the Test button.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Delete</td>
 
−
        <td>- (interactive button)</td>
 
−
        <td>Deletes the request.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Add</td>
 
−
        <td>- (interactive button)</td>
 
−
        <td>Adds a new request configuration.</td>
 
−
    </tr>
 
−
</table>
 
  
−
Under the “Request Configuration” section there will be another section called “Request Configuration Testing” this is where you can test that the parameters that you set work properly. Just select the request that you want to test and click the test button and you should get and output.
+
[[File:Testing modbus TCP client data.png|border|class=tlt-border]]
  
−
[[File:ExampleModSlave12Edit.png|border|class=tlt-border|center|Testing request.]]
+
=See Also=
  
−
==Alarms==
+
Most Teltonika-Networks devices have the Modbus feature. Configuration is described in the user manual Services page for each device.
−
Alarms are a way of setting up automated actions when some Modbus values meet user-specified conditions. To configure these alarms, scroll to the end of the menu and click the “Add” button.
 
−
 
 
−
[[File:ExampleModSlave13Edit.png|border|class=tlt-border|center|Add new alarm.]]
 
−
 
 
−
After clicking the “Add” button the next menu should come up:
 
−
 
 
−
[[File:ExampleModSlave14Edit.png|border|class=tlt-border|center|Alarm configuration.]]
 
−
 
 
−
<table class="nd-mantable">
 
−
    <tr>
 
−
        <th>Field</th>
 
−
        <th>Value</th>
 
−
        <th>Description</th>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Enabled</td>
 
−
        <td>yes | no; default: <b>no</b></td>
 
−
        <td>Turns the alarm on or off</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Function code</td>
 
−
        <td>Read Coil Status (1) | Read Input Status (2) | Read Holding Registers (3) | Read Input Registers (4); default: <b>Read Coil Status (1)</b></td>
 
−
        <td>Modbus function used in Modbus request.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Register</td>
 
−
        <td>integer [0..65535]; default: <b>none</b></td>
 
−
        <td>Number of the Modbus coil/input/holding register/input register that will be read.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Condition</td>
 
−
        <td>More than | Less than | Equal to | Not Equal to; default: <b>Equal to</b></td>
 
−
        <td>When a value is obtained it will be compared against the value specified in the following field. The comparison will be made in accordance with the condition specified in this field.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Value</td>
 
−
        <td>various; default: <b>none</b></td>
 
−
        <td>The value against which the read data will be compared.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td>Action</td>
 
−
        <td>SMS | Trigger output | Modbus Request; default: <b>SMS</b></td>
 
−
        <td>Action that will be taken if the condition is met. Possible actions:
 
−
            <ul>
 
−
                <li><b>SMS</b> - sends and SMS message to a specified recipient(s).</li>
 
−
                <li><b>Trigger output</b> - changes the state of a specified output(s).</li>
 
−
                <li><b>Modbus Request</b> - sends a Modbus request to a specified slave.</li>
 
−
            </ul>
 
−
        </td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: #0054a6;">SMS: Message</span></td>
 
−
        <td>string; default: <b>none</b></td>
 
−
        <td>SMS message text.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: #0054a6;">SMS: Phone number</span></td>
 
−
        <td>phone number; default: <b>none</b></td>
 
−
        <td>Recipient's phone number.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: red;">Trigger output: Output</span></td>
 
−
        <td>Open collector output | Relay output | Both; default: <b>Open collector output</b></td>
 
−
        <td>Which output(s) will be triggered.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: red;">Trigger output: I/O Action</span></td>
 
−
        <td>Turn On | Turn Off | Invert; default: <b>Turn On</b></td>
 
−
        <td>Action that will taken on the specified output.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: IP address</span></td>
 
−
        <td>ip | host; default: <b>none</b></td>
 
−
        <td>Modbus slave's IP address.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: Port</span></td>
 
−
        <td>integer [0..65535]; default: <b>none</b></td>
 
−
        <td>Modbus slave's port.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: Timeout</span></td>
 
−
        <td>integer [1..30]; default: <b>5</b></td>
 
−
        <td>Maximum time to wait for a response.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: ID</span></td>
 
−
        <td>integer [1..255]; default: <b>none</b></td>
 
−
        <td>Modbus slave ID.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: Modbus function</span></td>
 
−
        <td>Read Coil Status (1) | Read Input Status (2) | Read Holding Registers (3) | Read Input Registers (4) | Force Single Coil (5) | Preset Single Register (6) | Force Multiple Coils (15) | Force Multiple Registers (16); default: <b>Force Single Coil (5)</b></td>
 
−
        <td>A function code specifies the type of register being addressed by a Modbus request.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: First register</span></td>
 
−
        <td>integer [0..65535]; default: <b>none</b></td>
 
−
        <td>Begins reading from the register specified in this field.</td>
 
−
    </tr>
 
−
    <tr>
 
−
        <td><span style="color: purple;">Modbus Request: Number of registers</span></td>
 
−
        <td>integer [0..65535]; default: <b>none</b></td>
 
−
        <td>The number of registers that will be read from the first register.</td>
 
−
    </tr>
 
−
</table>
 

Latest revision as of 13:08, 7 October 2024

The information on this page is updated in accordance with the 00.07.09 firmware version .

Summary

This article contains instructions on how to configure Modbus TCP functionality on most of the Teltonika Networks devices (with the exception of TAP and TSW series)

Configuration overview & prerequisites

Before we begin, let's take a look at the configuration that we are attempting to achieve and the prerequisites that make it possible.

Configuring port forwarding on Teltonika devices is a simple process that involves just a few steps and can easily be replicated across various devices. The number of devices involved will depend on the specific use case, but the setup can be scaled seamlessly. In the example below, we will use the RUTX50 as the Modbus TCP Client and RUT956 as Modbus TCP Server.

Networking Topology Modbus basic config.png

Prerequisites:

  • A device from the RUT, RUTX, RUTM, RUTC or TRB series gateway;
  • A PC, Laptop, tablet or a smartphone
  • Router acting as Modbus TCP Server must have a SIM card with a Public Static or Public Dynamic IP address (more on IP address types here) to make remote access possible
  • (Optional) If the router's SIM card has a Public Dynamic IP address, you may want to additionally configure a Dynamic DNS hostname

If you're having trouble finding this page or some of the parameters described here on your device's WebUI, you should turn on "Advanced WebUI" mode. You can do that by clicking the "Advanced" button, located at the top of the WebUI.

Networking rutos manual webui basic advanced mode 75.gif

Modbus TCP Server

Configure Modbus TCP Server device. our slave device to have a 192.168.1.2 internal IP address. This can be done by changing the IP address parameter on Network → WAN page:

Modbus TCP Server configuration

Setup router as Modbus TCP Server. It can be done in Services → Modbus → Modbus TCP Server . Once in the Modbus TCP Server configuration, find the Enable the instance and everything else can be left as default or changed based on your needs:

Enable modbus tcp server.png

Once finished click Save & Apply to save the configuration.

Remote access configuration

If you wish to remotely access the Modbus TCP Server device navigate to the System → Administration → Access Control tab. Once in the Administration-Access Control, find the Enable remote HTTP access field and put a check mark next to it:

Enable remote access HTTP.png

Note: If you have a Public IP address already, you can skip this step.

To set the APN, while in the router's WebUI, navigate to the Network → Mobile → General → Interface mob1s1a1 APN configuration:

Once in the Interface mob1s1a1 APN configuration window, edit your mobile interface, find the APN field and enter you Internet Service Provider's APN:

  1. Disable the Auto APN option
  2. Choose the correct APN, which gives out a public IP address (for more information about that contact your Internet Service Provider)

Set APN PF APN selected.png

Additional notes on APN:

  • NOTE 1: don't use the exact APN value as seen in the example above as it will not work with your SIM card. APN depends on your Internet Service Provider (ISP), therefore, your ISP should provide you with their APN or, in many case, you can find your ISP's APN with an online search.
  • NOTE 2: furthermore, it should be noted that not all SIM cards support this functionality. Static or Dynamic Public IP addresses (obtained through APN) are a paid service and setting any APN value for a SIM card that doesn't support this service will most likely result in losing your data connection. If this is the case, it can be fixed by simply deleting the APN, but it also means that remote access through mobile WAN IP will most likely not work on your SIM card.
  • NOTE 3: in some cases the SIM card doesn't require an APN in order to obtain a Public IP address. If that is the case for you, simply check what your router's mobile WAN IP address is - if it's already a Public IP address, then you don't need to set an APN. The easiest way to find what your mobile WAN IP address is to log in to the router's WebUI and check the MOB1S1A1 widget in the Overview page:

Where public IP.png

Modbus TCP Client

Modbus TCP Client configuration

On the Modbus TCP Client device open Services → Modbus → Modbus TCP Client. To create a new instance click on Add. A new pop-up window should appear:

  1. Enable the instance
  2. Enter the desired name
  3. Server ID must match with the previously configured Server device ID
  4. Enter the mobile WAN IP address of the Modbus TCP Server device
  5. Chose same Port as in Server device - 502
  6. Enter Period in seconds, how often requests will be sent to the Server device

Enable modbus tcp client config.png

Requesting Modbus data

For testing, if the functionality is working we can configure a request. A Modbus request is a way of obtaining data from Modbus Server. The Client sends a request to a Server specifying the function code to be performed. The Server then sends the requested data back to the Modbus Client.

Scroll down to the Request configuration section. Write a name for the request and click the Add button:

Add new request modbus tcp client.png

In this case we are trying to get System temperature (in 0.1 °C) information so configure the next options:

  1. Data type: 32bit INT, Byte order 1,2,3,4
  2. Function: Read holding registers (3)
  3. First register: 6
  4. Number of registers: 2
  5. Enble brackets if not needed
  6. Enable the request

The information about correct Modbus registers usage can be found [here].

Add new request modbus tcp test.png

Under the Request Configuration section there will be another section called Request Configuration Testing this is where you can test that the parameters that you set work properly. Just select the request that you want to test and click the test button and you should get an output.

Testing modbus TCP client data.png

See Also

Most Teltonika-Networks devices have the Modbus feature. Configuration is described in the user manual Services page for each device.

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