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Hello,

is there is some possibility to change Unit ID (slave ID) of Modbus TCP device ?
I use ModbusClient in Java and device only response on 255 Slave ID (but, i see from code that easymodbus have set 1)

Thank you

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Hi,

the unitIdentifier is a byte. In Java the byte datatyp is from -128 to 127 which means you can't address devices with a unitId above 127.
It worked with a device with unitId=32.

Good morning,

checking in the source code of ModbusClient, I found that the method named ConvertRegistersToDouble has a different behaviour from what its name suggests.

The first thing I expected from this method was a double return type, but the return type is int. I don't understand how to manage this value to obtain the expected double value.
The second strange thing is that, as double values are represented by 64 bits, to read the bits that composes the value I will read 4 registers from the modbus server. But the method allow only an int[] input with length = 2 (otherwise it throws an exception).

Reading from the online documentation here http://easymodbustcp.net/java-modbusclient-methods, it seems that the correct behavior is read 2 registers and obtain an int as response (see the method in the list, there's an example).

Can you please explain the correct way to use this method and, if with this method isn't possible, if there's another way to use ModbusClient to read 4 registers and convert it to a double value?

Thanks in advance,
Regards

Hello, I'm having trouble reading an input register (0x0758) using modbus from a Slave. I tried to implement the examples provided but I don't know if I'm doing it right as the value returned is not the expected... . Could you please point me in the right direction?

package com.test.modbus.main;

import de.re.easymodbus.modbusclient.ModbusClient;

public class Main {
	
	public static String SLAVE_ADDR = "xx.xx.xx.xx";

	
	public static void main(String[] args) {
		
		
		
		ModbusClient modbusClient = new ModbusClient(SLAVE_ADDR,502);
		try
		{
			modbusClient.Connect();
			int value = modbusClient.ReadInputRegisters(Integer.decode("0x0758"), 1)[0];
			System.out.println("Value at 0x0758: " + value);

		}
		catch (Exception e)
		{		
			System.out.println(e);
		}	
	}

}

It gives me Quantity invalid. I need to retrieve the value and then convert it to float but I'm a little bit lost

I have written a small java program which connects to a modbus server and reads Coils ok. When I run my code and the modbus device is not online it seems to wait indefinately and does not timeout. I have experimented with the setConnectionTimeout option but it does not seem to make any difference. Any ideas ?

In all te constructors of ModbusClient four lines are output to stdout. I am using ModbusClient to periotically read values from my PV inverter, every 5 seconds. Hence my stdout log is becoming pretty big.

Would you mind, giving an option to shut up this output?

A related question: Is it by any means problematic to reuse a single instance of a ModbusClient for the whole lifetime of the application? It doesn't need to be thread safe (is it?). But bit would need to be completely reusable and hence stateless apart from what I passed into the constructor. In that case I would be ok with the four lines of output.

Hiii,
I just started with using the EasyModbusTCP library in Java,
I tried to read some data from a device using this protocol, and it worked fine except some values where shifted in the registers, here is an example of output:

656d 732e 636d 2e74 6e00 ffffc0a8 232f
as you can see in the 6th register the 'ffff' values weren't supposed to be there,
I tried to read the values with another lib in python and it work fine, so I am sure that the problem is in the client.
Can anyone help me

Hello.
Every client connection to Easy Modbus Server a new thread is created, but at the disconnect it didn't kills. If we have 1k connect-disconnect we have a 1k threads.