Modbus Rtu Slave

Overview

Modbus itself is a specification for information exchange. Modbus RTU is a way to implement Modbus via serial ports, so all information is transmitted through serial ports. The Modbus protocol belongs to the C/S architecture. Modbus Rtu Slave is a server used to store all industrial equipment data to be read.

Application Scenarios

• Modbus belongs to the C/S architecture. In industrial settings, Modbus slave acts as a server to store all industrial equipment data to be read, such as temperature, humidity, distance, etc. The Modbus master can communicate with the slave via a serial port connection.

Overall Architecture

• Modbus Tcp is a way to implement Modbus via serial ports. The Modbus Rtu Master can send read or write commands to the Rtu Slave. After receiving the command, the Slave will reply with confirmation information. The entire Modbus communication is based on the round-trip message exchange.

• The following table outlines each product component

Installation and Uninstallation

Installation Requirements

• Sinsegye's factory-produced iComputer;

• The iComputer can access the Internet;

• Familiarity with basic Linux operation commands;

Installation Process

Install Modbus Tcp Slave RTE Component on iComputer

• Upload the deb package to the /home/sinsegye directory of the iComputer's Linux environment

• After the upload is complete, execute the command on the iComputer to install (refer to the screenshot below; if the module file name changes, modify the file name in the command line accordingly)

cd $HOME
sudo dpkg -i modbusslave_0.0.5_amd64.deb

• Modify the RTE configuration file, add modbusslave under the ComponentManager field

sudo nano /usr/local/etc/SinsegyeRTE/SinsegyeRTE.cfg

ComponentManager]
 Component.0=retainDeamon
 Component.1=CmpCanBusUtils
 Component.2=CmpSinsegyeLibs
 Component.3=SinsegyeCmp
 Component.4=modbusslave

• Restart the RTE service to make the newly added modbusslave be invoked

sudo systemctl restart sinsegyerte.service

Install Library on Metafacture

• Open Metafacture, click "Tools" -- "Library Storage"
  

• Click "Install" -- select the modbus slave library file, click "Open"
  

• In the project, click "Library Manager" -- "Add Library" -- select the modbus library and click "OK"
  

Update Installation
Upgrade Modbus Tcp Slave RTE Component on iComputer

• Upload the deb package to the /home/sinsegye directory of the iComputer's Linux environment

• After the upload is complete, execute the command on the iComputer to install (refer to the screenshot below; if the module file name changes, modify the file name in the command line accordingly)

cd $HOME
sudo dpkg -i modbusslave_0.0.5_amd64.deb

• Restart the RTE service to make the newly upgraded modbusslave be invoked

sudo systemctl restart sinsegyerte.service

Upgrade Library on Metafacture

• Open Metafacture, click "Tools" -- "Library Storage"
  

• Click "Install" -- select the modbus slave library file to be upgraded, click "Open"
  

• In the project, click "Library Manager" -- "Add Library" -- select the modbus library and click "OK"
  

Uninstallation Process

Uninstall Modbus Tcp Slave RTE Component on iComputer

• Execute the command on the iComputer to uninstall modbusslave

sudo dpkg -r modbusslave

• Modify the RTE configuration file, remove modbusslave from the ComponentManager field

sudo nano /usr/local/etc/SinsegyeRTE/SinsegyeRTE.cfg

• Restart the RTE service

sudo systemctl restart sinsegyerte.service

Uninstall Modbus Tcp Slave Library on MetaFacture

• On the MetaFacture interface, click "Tools" -- "Library Storage"
  

• In the dialog box, select the installed modbus slave library and click "Uninstall"
  

Technical Description

Quick Start

Software and Hardware Configuration in This Example

Hardware:

1. SX5100 iComputer MetaOS V24.08.15_SX5

2. Win10 PC

Software:

1. MetaFacture V1.0.6.3

2. Modbus Poll master tool

Experimental Requirements and Principles in This Example

• Experimental requirement: Configure the Modbus Rtu Slave environment according to the "Installation Process" in the "Installation and Uninstallation" section.

Experimental Principle

• A third-party Modbus Rtu master sends requests to the Metafacture Modbus Rtu slave via a serial port connection, which mainly includes: function code, address and quantity of target registers, and data for write operations. After receiving the request, the slave first checks the validity of the data, then executes the requested operation and responds to the master's request.

• The host computer and the iComputer are connected via Ethernet.

• On the host computer, Metafacture downloads the project to the iComputer. The project will include the configurations in the experimental operation steps below.

• The iComputer is connected to the third-party Modbus Rtu master via a serial port.

Experimental Operation Steps in This Example

The experimental steps for creating a Modbus tcp slave project are as follows:

• Declare and call the modbus rtu slave function block in the POU area, configure 2048 points each for coils, discrete inputs, holding registers, and input registers;

PROGRAM rtu_slave
VAR
        FB_Modbus_Com_Slave_0      : ModbusSlave.FB_Modbus_Com_Slave;
        bxEnable                   : BOOL:=TRUE;
        pbyCoilA                   : ARRAY [0..2048] OF BOOL;
        pbyDiscreteInputA          : ARRAY [0..2048] OF BOOL;
        pbyInputRegisterA          : ARRAY [0..2048] OF WORD;
        pbyHoldingRegisterA        : ARRAY [0..2048] OF word;
        bBusy                      : BOOL;
        bActive                    : BOOL;
        bError                     : BOOL;
        eError                     : BOOL;
        ulRecvCounter              : UDINT;
        ulSendCounter              : UDINT;  
END_VAR

• Call FB_Modbus_Com_Slave_0 in the program area of the POU, configure the slave COM port, slave ID, serial port baud rate, coil address, holding register address, discrete input address, input register address, etc.;

FB_Modbus_Com_Slave_0(
        bEnable               :=bxEnable ,
        uiSlaveId             :=1 ,
        comPort               :=ModbusSlave.COM_PORT.ttys6 ,   //SX5  ttys6、 SX58 ttyS0、SX2 ttyS0;
        baudrate              :=ModbusSlave.SERIAL_BAUDRATE.baudrate_115200 ,
        byteSize              :=ModbusSlave.SERIAL_DATABIT.databit_8 ,
        parity                :=ModbusSlave.SERIAL_PARITY.parity_no ,   //The master should also be set to this
        stopBits              :=ModbusSlave.SERIAL_STOPBIT.stopbit_1 ,
        udiTimeOut            :=10000 ,
        psMbTest              := ,
        pbyCoil               :=ADR(pbyCoilA),
        pbyDiscreteInput      :=ADR(pbyDiscreteInputA),
        pbyInputRegister      :=ADR(pbyInputRegisterA),
        pbyHoldingRegister    :=ADR(pbyHoldingRegisterA),
        udiRwBitSize          :=SIZEOF(pbyCoilA),
        udiInBitSize          :=SIZEOF(pbyDiscreteInputA),
        udiInWordSize         :=SIZEOF(pbyInputRegisterA),
        udiRwWordSize         :=SIZEOF(pbyInputRegisterA),
        bBusy=> ,
        bActive=> ,
        bConnect=> ,
        bError=> ,
        eError=> ,
        ulRecvCounter=> ,
        ulSendCounter=> );

• After the project runs, you can use Modbus Poll to connect to the Metafacture Rtu Slave to read and write operations on the slave; the data of the master and slave are consistent;

Creating Modbus Rtu Slave

Introduction to Function Block FB

Parameter Introduction

Input Parameters

Output Parameters