TECHNOLOGIES
FORUMS
JOBS
BOOKS
EVENTS
INTERVIEWS
Live
MORE
LEARN
Training
CAREER
MEMBERS
VIDEOS
NEWS
BLOGS
Sign Up
Login
No unread comment.
View All Comments
No unread message.
View All Messages
No unread notification.
View All Notifications
Answers
Post
An Article
A Blog
A News
A Video
An EBook
An Interview Question
Ask Question
Forums
Monthly Leaders
Forum guidelines
Emma Emma
NA
101
55.4k
Modbus RTU master software design
Jun 6 2013 5:36 AM
Hi
I am working one designing one windows based software which can read the register values from Modbus RTU slave register or man can say PLC. I got the NMODBUS library, here is the code:
using (SerialPort port = new SerialPort(ComBox.Text))
{
// configure serial port
port.BaudRate = Convert.ToInt16(BaudBox.Text.ToString());
port.DataBits = 8;
port.Parity = Parity.None;
port.StopBits = StopBits.One;
port.Open();
// create modbus master
IModbusSerialMaster master = ModbusSerialMaster. CreateRtu(port);
byte slaveId =Convert.ToByte(SlaveID2.Text.ToString());
ushort startAddress = 40000;
ushort numRegisters = 10;
// read five registers
ushort[] registers = master.ReadHoldingRegisters(slaveId, startAddress, numRegisters);
for (int i = 0; i < numRegisters; i++)
Console.WriteLine("Register {0}={1}", startAddress + i, registers[i]);
}
I got one problem like this:
The problem is :
Exception of type 'Modbus.SlaveException' was thrown.
Function Code: 131
Exception Code: 2 - The data address received in the query is not an allowable address for the server (or slave). More specifically, the combination of reference number and transfer length is invalid. For a controller with 100 registers, the PDU addresses the first register as 0, and the last one as 99. If a request is submitted with a starting register address of 96 and a quantity of registers of 4, then this request will successfully operate (address-wise at least) on registers 96, 97, 98, 99. If a request is submitted with a starting register address of 96 and a quantity of registers of 5, then this request will fail with Exception Code 0x02 "Illegal Data Address" since it attempts to operate on registers 96, 97, 98, 99 and 100, and there is no register with address 100.
Please anyone can help???Thanks so much...
Reply
Answers (
0
)
ReportViewer in C#
Hash Table