C # Modbus Data read using NMODBUS4 Library

Source: Internet
Author: User

Modbus Communication Protocol

Method name

Role

Required Parameters

return value

corresponding function code

Readcoils

Read the status of Do

Slave address (8-bit)

BYTE slaveaddress

Start address (16-bit)

UShort Startaddress

Number of reads (16-bit)

UShort Numberofpoints

Bool[]

01

Readinputs

Read the state of Di

Slave address (8-bit)

BYTE slaveaddress

Start address (16-bit)

UShort Startaddress

Number of reads (16-bit)

UShort Numberofpoints

Bool[]

02

Readholdingregisters

Read the value of AO

Slave address (8-bit)

BYTE slaveaddress

Start address (16-bit)

UShort Startaddress

Number of reads (16-bit)

UShort Numberofpoints

Ushort[]

03

Readinputregisters

Read the value of AI

Slave address (8-bit)

BYTE slaveaddress

Start address (16-bit)

UShort Startaddress

Number of reads (16-bit)

UShort Numberofpoints

Ushort[]

04

Writesinglecoil

Write value to do

Slave address (8-bit)

BYTE slaveaddress

Coil Address (16-bit)

UShort Coiladdress

Write Value (Boolean)

BOOL Value

No return value

05

Writesingleregister

Write value to AO

Slave address (8-bit)

BYTE slaveaddress

Register address (16-bit)

UShort Registeraddress

Write value (16-bit)

UShort Value

No return value

06

Writemultiplecoils

Write multi-coil registers

Slave address (8-bit)

BYTE slaveaddress

Start address (16-bit)

UShort Startaddress

Write value (Boolean array)

Bool[] Data

No return value

15

Writemultipleregisters

Write multiple hold Registers

Slave address (8-bit)

BYTE slaveaddress

Start address (16-bit)

UShort Startaddress,

Register value (16-bit integer array)

Ushort[] Data

No return value

16

Readwritemultipleregisters

Read and write multiple hold registers

Slave address (8-bit)

BYTE slaveaddress

Read start address (16-bit)

UShort Startreadaddress

Number of reads (16-bit)

UShort Numberofpointstoread,

Write start address (16-bit)

UShort Startwriteaddress,

Write value (16-bit integer array)

Ushort[] WriteData

Ushort[]

23

Modbus Slave

This is the installation package Modbusslavesetup64bit registration code:54555451475662

Modbus Communication Protocol Net Library

This is a lot of open source libraries, my side of the library is GitHub's open Source implementation class Library: Nmodbus4,github address: HTTPS://GITHUB.COM/NMODBUS4/NMODBUS4

I use Modbus slave to simulate a slave machine

Setting up data

NMODBUS4 Read Slave code example

1IPAddress address =NewIPAddress (New byte[] {127,0,0,1 });2             using(TcpClient client =NewTcpClient (address. ToString (),502))3             {4Client. Sendtimeout =1;5                 //Client.op6Modbusipmaster master =modbusipmaster.createip (client);7                 //Master.op8                 //read five input values9                 ushortStartaddress =0;Ten                 ushortNuminputs =Ten; One                 BOOL[] inputs = Master. Readcoils (1, startaddress, numinputs); A  -                  for(inti =0; i < numinputs; i++) -                 { theConsole.WriteLine ($"Input {(startaddress + i)}={(inputs[i]? 1:0)}"); -                 } -  -}

Here is worth noting is the host read method the first parameter is SlaveID if not added startaddress and numinputs Nmodbus will default SlaveID is 01 straight exception (d (╯﹏╰) B painful experience ~ ~)

The above data is the do state just set

In the demo of a read AI value

The code is not bad how much is the method readinputregisters different. Here is the sample code

1IPAddress address =NewIPAddress (New byte[] {127,0,0,1 });2             using(TcpClient client =NewTcpClient (address. ToString (),502))3             {4Client. Sendtimeout =1;5                 //Client.op6Modbusipmaster master =modbusipmaster.createip (client);7                 //Master.op8                 //read five input values9                 ushortStartaddress =0;Ten                 ushortNuminputs =Ten; One                 ushort[] inputs = Master. Readinputregisters (2, startaddress, numinputs); A  -                  for(inti =0; i < numinputs; i++) -                 { theConsole.WriteLine ($"Register {(startaddress + i)}={(Inputs[i])}"); -                 } -  -}

C # Modbus Data read using NMODBUS4 Library

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