QModbusServer on Raspberry Pi: Connection Refused by Server

aniketRoxy

Hi,
I have created QModbusServer (TCP) in my application on windows 10 laptop.
Following code is for create tcp modbus server.

const QUrl url = QUrl::fromUserInput("127.0.0.1:1502");
modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, url.host());```
modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, url.port());
modbusDevice->setServerAddress(1);

Server is running well. I can connect my LabVIEW Modbus Client application from same Laptop.
Now I started server application on raspberry pi.
During connect request from laptop, LabVIEW modbus client shows following error.

LabVIEW: Serial buffer overflow, Connection refused by server & terminated.

aniketRoxy

I changed code as following, now working fine.

//const QUrl url = QUrl::fromUserInput("127.0.0.1:1502");
modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, "localhost");
modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, 1502);
modbusDevice->setServerAddress(1);

"127.0.0.1" is loopback address, which refuses remote connection.

aniketRoxy

I changed code as following, now working fine.

//const QUrl url = QUrl::fromUserInput("127.0.0.1:1502");
modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, "localhost");
modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, 1502);
modbusDevice->setServerAddress(1);

"127.0.0.1" is loopback address, which refuses remote connection.

Solved QModbusServer on Raspberry Pi: Connection Refused by Server