Application Note Modbus RTU Gateway Master...Modbus RTU Gateway Master 2 Chapter 1 Introduction 1.1...

Modbus RTU Gateway Master

Application Note

Version: v.1.0.1

Date: 2017-04-01

Status: Confidential

Doc ID: Modbus RTU Gateway Master

Author: Sunny Guo

www.robustel.com


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Contents

Chapter 1 Introduction ........................................................................................................................................ 2

1.1 Overview ............................................................................................................................................. 2

1.2 Assumptions ....................................................................................................................................... 2

1.3 Rectifications ...................................................................................................................................... 3

1.4 Version ................................................................................................................................................ 3

Chapter 2 Topology ............................................................................................................................................. 4

Chapter 3 Configuration ...................................................................................................................................... 5

3.1 Install Modbus Poll ............................................................................................................................. 6

3.2 Install Modbus Slave ........................................................................................................................... 9

3.3 R3000_ROS Configuration ................................................................................................................ 11

3.3.1. Configure Link Manager ................................................................................................................... 11

3.3.2. Configure Cellular WAN .................................................................................................................... 13

3.3.3. Configure Serial ................................................................................................................................ 15

Chapter 4 Testing ............................................................................................................................................... 18

4.1 Network Status ................................................................................................................................. 18

4.2 Run Modbus Slave ............................................................................................................................ 19

4.3 Run Modbus Poll ............................................................................................................................... 21

4.4 Communication process ................................................................................................................... 24

4.5 Serial Port Status............................................................................................................................... 26


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Chapter 1 Introduction

1.1 Overview

RobustOS (hereinafter referred to as “the ROS”) is a new operating system for Robustel's IoT gateway released in

2015. It is a modular and open software platform which could support third party development based on SDK/API.

Meanwhile, it supports different routing and VPN protocols for different application scenarios. This newer platform

provides a different web configuration interface than the existing platform.

R3000 supports Modbus RTU to Modbus TCP protocol transformation. It can be set as TCP client if it gets a public IP

address, and then Modbus Poll site acting as TCP Client can connect to Server via TCP connection and poll the

Modbus TCP data to R3000.

This application note has been written for customer with a good understanding of Robustel products and a basic

experience of VPN.

1.2 Assumptions

This application note has been written by technically competent engineer who is familiar with the Robustel products

and the application requirements.

This application note is based on:

Product model: Robustel GoRugged R3000, an industrial cellular VPN router

Firmware version: R3000_ROS_V2.0.3

Configuration: This application note assumes the Robustel products are set to factory default. Most of

configuration steps are only shown if they are different from the factory default settings.


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1.3 Rectifications

Requests for corrections or rectifications to this application note will be appreciated, and if there are any request for

new application notes please email to: [email protected].

1.4 Version

Updates between document versions are cumulative. Therefore, the latest document version contains all updates

made to previous versions.

Release Date Firmware Version Change Description

2017-02-08 v.1.0.0 Initial Release

2017-04-01 v.1.0.1 1. The File Name change:

Modbus Master -> Modbus RTU Gateway Master

2. The Cover change

3. Firmware version change:

R3000_ROS_V2.0.3.fs-> R3000_ROS_V2.0.3

mailto:[email protected]


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Chapter 2 Topology

1. Modbus Mater device acts as TCP Client, connects to Server and polls data to Modbus Slave device through

R3000.

2. The R3000 gets a public IP address and acts as TCP Client.

3. The R3000 works under “Modbus RTU Gateway” mode, receives Modbus TCP data, transforms to Modbus RTU

protocol, and then sends to Modbus Slave device via serial interface (RS-232 or RS-485).

4. After Modbus Slave device responding correctly, it will send data back to R3000 with Modbus RTU protocol, then

R3000 will transform data from Modbus RTU to Modbus TCP protocol and pass to Modbus master device via TCP

connection.

5. Modbus Master device receives data from Modbus Slave device and displays correctly.

6. In this Application Note, Modbus Poll software is simulated as Modbus Master device and Modbus Slave

software is simulated as Modbus Slave device. Modbus Slave connects to R3000 via the RS-232.


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Chapter 3 Configuration

Download Modbus Poll and Modbus Slave from http://www.Modbustools.com/download.asp.

http://www.modbustools.com/download.asp


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3.1 Install Modbus Poll

1. Run ModbusPollSetup.exe.

2. Choose “I accept the terms in the License Agreement” and click “Next”.


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3. Browse and specify a destination folder, then click “Next”.

4. Click “Install”.


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5. Click “Next” to finish the installation.


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3.2 Install Modbus Slave

1. Run ModbusSlaveSetup-431.exe.

2. Choose “I accept the terms in the License Agreement” and click “Next”.


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3. Browse and specify a destination folder, then click “Next”.

4. Click “Install”.


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5. Click “Next” to finish the installation.

3.3 R3000_ROS Configuration

3.3.1. Configure Link Manager

1. Follow these steps before configuring the router:

Attach the external antenna to the router’s connector and twist tightly

Insert the SIM card into the router

Connect the power supply correctly

Log in the Web GUI of the router


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You need to know the following factory settings before you have logged in the Web GUI.

Item Description

Username Admin

Password Admin

Eth0 192.168.0.1/255.255.255.0, LAN Mode

Eth1 192.168.0.1/255.255.255.0, LAN Mode

DHCP Server Enabled

2. Browse to Interface > Link Manager.

Click the drop-down list of “Primary Link” and select “WWAN1”.

Click “Submit”.

Click “Save & Apply”.

Item Description Setting

Primary Link Select “WWAN1”, “WWAN2” or “WAN” as the primary

connecting interface.

WWAN1


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3.3.2. Configure Cellular WAN

Browse to Interface > Link Manager > Link Settings.

Click the edit button of “WWAN1”.

Enter the related parameters in the “WWAN Settings” window.

Enter the related parameters in the “Ping Detection Settings” window.

Click “Submit”.


The window is displayed as below when enabling the “Automatic APN Selection” option.


Dialup Number Set the dialup number for cellular dial-up connection, provided

by local ISP.

*99***1#

Data Allowance Set the monthly data traffic limitation. 0

Billing Day Specify the monthly billing day, and the data traffic statistics will

be recalculated from this day.

1


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The window is displayed as below when disabling the “Automatic APN Selection” option.


APN Enter the Access Point Name for cellular dial-up connection,

provided by local ISP.

internet

Username Enter the username for cellular dial-up connection, provided by

local ISP.

Null

Password Enter the password for cellular dial-up connection, provided by

local ISP.

Null


Primary Server Router will ping this primary address/domain name to check if

the current connectivity is active.

8.8.8.8

Secondary Server Router will ping this secondary address/domain name to check if

the current connectivity is active.

Null

Interval Set the ping interval. 10


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Retry Interval Set the ping retry interval. 3

Timeout Set the ping timeout. 1

Max Ping Tries Switch to another link or take emergency action if max

continuous ping tries reached.

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3.3.3. Configure Serial

1. Browse to Interface > Serial Port.

Click the edit button of “COM1”.


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Configure the related parameters as the following diagram and click “Submit”.


Application Mode Select from “Modbus RTU Gateway” or “Transparent” Enter accordingly

Protocol Select from “TCP Client”, “TCP Server”, “UDP” or “Robustlink” Enter accordingly

Server Address Enter the IP address of the server. Enter accordingly

Server Port Enter the port of the server. Enter accordingly


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Chapter 4 Testing

4.1 Network Status

1. Click “Status” bar.

2. Check whether the ROS has obtained the assigned static IP address.

3. Check whether the ROS has used SIM card to register to network, dial up to get IP address and access the

Internet.


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4.2 Run Modbus Slave

1. Run Modbus Slave.

2. Go to tab “Setup > Slave Definition” to set the Modbus Slave ID. Its default value is 1.


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3. Go to tab “Connect”.

4. Select “TCP/IP” in the “Connection” item, and enter its port number. Now Modbus Poll is a TCP Client. It is the

same with the port number which has been set at section 3.3.3, then click “OK”.


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5. Go to “Alias” and change the value of different address. For example, change value to “1, 2, 3….”.

Note: Setting change is used to check if Modbus Poll site’s correspondent address would change to the same

value as Modbus Slave.

4.3 Run Modbus Poll

1. Run Modbus Poll.

2. Go to tab “Setup > Slave Definition” to set the Modbus Slave ID which must be the same with the “Slave ID” that

is set in Modbus Slave. Its default value is 1.


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3. Click “Connection > Connect”.


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4. Choose “Serial Port” as the connection, connect to R3000’s serial port and set the same settings of R3000’s

serial settings. Choose “RTU” as the mode and click “OK”.

Note: “RTU” mode means that Modbus Slave sending data out with Modbus RTU mode.

5. After step 4, if the TCP connection has been set up between PC and R3000, it will show us the following figure.

TX number is improving, which means the Modbus Poll has already sent data out based on the connection. The

test is successful.

Note: If wrong port number input, we cannot establish the TCP connection. By contrast, it will show us the

following figure:


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4.4 Communication process

We can also click “Display > Communication” in both Modbus Slave and Modbus Poll to check whether the source

data is correct. Data displaying is based on Modbus RTU or Modbus TCP protocol.

1. In Modbus Slave site, go to tab “Display > Communication”.


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2. In Modbus Poll site, go to tab “Display > Communication”.


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4.5 Serial Port Status

Application Note Modbus RTU Gateway Master...Modbus RTU Gateway Master 2 Chapter 1 Introduction 1.1...

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