I would need to customize the QModbusDataUnit by sending custom hex via modbus, below my code, I'm trying to customize the post but I do not understand how to do it.
I should send the following values: 0x01,0x08,0x00,0x00,0x00,0x00,0xE0,0x0B
void connessione::clickButton(){
QModbusDataUnit readUnit(QModbusDataUnit::HoldingRegisters, 1, QVector<quint16>({0x01,0x08,0x00,0x00,0x00,0x00,0xE0,0x0B}));
qDebug() << "readUnit" << clientX->state();
if (auto *reply = clientX->sendReadRequest(readUnit, 255)) // client id 255
{
if (!reply->isFinished())
{
// connect the finished signal of the request to your read slot
qDebug() << "connected" << reply->errorString();
connect(reply, &QModbusReply::finished, this, &connessione::readReady);
}
else
{
qDebug() << "Errore" << reply->errorString();
delete reply; // broadcast replies return immediately
}
}
else
{
qDebug() << "Errore" << reply->errorString();
// request error
}
}
but my response is:
D/libmodbusMobile.so(15006): (null):0 ((null)): qt.modbus: (TCP
client) Sent TCP PDU: 0x0300080008 with tId: 0
where set 0x03 ?
this is not right, it's not equal to my QVector send, how to solve ?
Try to test a QModbusDataUnit as follows:
QModbusDataUnit myUnit;
QModbusDataUnit::RegisterType myType;
myType = static_cast<QModbusDataUnit::RegisterType>(0x04);
myUnit = QModbusDataUnit(myType,0x0c,0x03);
cout << hex;
cout << myUnit.registerType() << endl;
cout << myUnit.startAddress() << endl;
Notes:
To use “cout” in a console QT application;
#include <iostream>
using namespace std;
To create a QT Modbus console application include the following in the .pro file;
QT += serialbus widgets
qtConfig(modbus-serialport): QT += serialport
TARGET = modbusserver
Related
I created a library which will handle all HTTP requests and parsing of response data in JSON format. When I called the method that includes get request in my main application (with GUI), I received a memory corruption error. So I added QEventLoop and a timer to wait for the response before proceeding to other processes. I was able to get the response data by calling QNetworkReply.readall(). I needed to get the char* value of the response data so I called the QNetworkReply.data() but it is empty. Why?
Here are the codes I wrote:
Library which handles HTTP requests:
void HttpRequest::getRequest(string param1, string param2)
{
pManager_ = new QNetworkAccessManager(this);
QUrl cUrl(sampleUrl);
QNetworkRequest request(cUrl);
request.setRawHeader(keyHeader.c_str(), param1.c_str());
connect(pManager_, SIGNAL(finished(QNetworkReply*)), this, SLOT(requestFinished(QNetworkReply*)));
connect(pManager_, SIGNAL(sslErrors(QNetworkReply*, const QList<QSslError> & )), this,
SLOT(handleSslErrors(QNetworkReply*, const QList<QSslError> & )));
cUrl.addQueryItem("name", QString::fromStdString(param2));
pManager_->get(request); // memory corruption error encountered in main application after calling this
std::cout << "after calling get" << std::endl;
}
void HttpRequest::requestFinished(QNetworkReply *pReply)
{
QByteArray responseData;
std::cout << " request finished" << std::endl;
int responseStatus = pReply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
std::cout << " status code: " << responseStatus << std::endl;
if(pReply->error())
std::cout << " Error: " << pReply->errorString().toStdString() << std::endl;
else
{
responseData = pReply->readAll();
qDebug() << " Response data: " << responseData;
const char* pResponseData = responseData.data();
qDebug() << "pResponseData: " << pResponseData ;
// parsing here
}
pReply->deleteLater();
pManager_->deleteLater();
}
void HttpRequest::handleSslErrors(QNetworkReply *pReply, const QList<QSslError> & )
{
std::cout << " SSL ERROR" << std::endl;
int responseStatus = pReply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
}
Main GUI application:
DialogTest::DialogTest(QWidget *parent) :
QDialog(parent),
ui(new Ui::DialogTest)
{
// some codes here
if(enabled)
{
HttpRequest::instance()->getInformation(param1, param2); // memory corruption happened here when I called getRequest() method with no event loop
}
// other threads here
}
Here is the code that uses QEventLoop:
void HttpRequest::getRequest(string param1, string param2)
{
QTimer qTimer;
QEventLoop loop;
pManager_ = new QNetworkAccessManager(this);
QUrl cUrl(sampleUrl);
QNetworkRequest request(cUrl);
request.setRawHeader(keyHeader.c_str(), param1.c_str());
connect(&qTimer,SIGNAL(timeout()),&loop, SLOT(quit()));
connect(pManager_, SIGNAL(finished(QNetworkReply*)),&loop, SLOT(quit()));
QNetworkReply *pReply = pManager_->get(request);
qTimer.start(1000);
loop.exec();
int responseCode = pReply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
std::cout << "status code: " << responseCode << std::endl;
if(pReply->error())
{
std::cout << " Error: " << pReply->errorString().toStdString() << std::endl;
}
else
{
qDebug() << "[HttpRequest] Response data: " << pReply->readAll();
QByteArray response = pReply->readAll(); // it printed this value: "{"count":3,"codes":["x00000A","x00000B","x00000C"]}" which is correct
char* pResponseData = response.data();
qDebug() << "pResponseData: " << pResponseData ; //it printed this: pResponseData:
}
delete pReply;
delete pManager_;
}
I am expecting this response data from a HTTP get command:
"{"count":3,"codes":["x00000A","x00000B","x00000C"]}"
Problem:
What is the best way to implement this? I want to put all HTTP request in a library then call it my main application with GUI. Please note that:
When I use QEventLoop inside the library to wait for the response, QNetworkReply.data() is empty. I need the value of QNetworkReply.data() for parsing.
When I did not use QEventLoop and use signal and slot alone (as shown in the code above), memory corruption occurred in main application after executing HTTP get command. No response data is received.
an advice:
never use a direct delete for a QObject. BAD:
delete pReply;
delete pManager_;
Qt way,GOOD:
pReply->deleteLater();
pManager->deleteLater();
Better: no "new" (dynamic memory)
QNetworkAccessManager Manager_;
...
connect(&Manager_, SIGNAL(finished(QNetworkReply*)),&loop, SLOT(quit()));
..
pReply->deleteLater();
I'm having trouble sending data from a server to a client using Qt. Whenever I do QTcpSocket::waitForBytesWritten() after a call to QTcpSocket::write(...), it returns false.
I tried using the bytesWritten signal, but that never gets emitted, presumably because no data is able to be written, and no data is received on the client side.
The writeData method is what is being called in the MainWindow class, but to try and narrow down the cause of the problem, I moved the writing of data to the client into the newConnection method.
The message Connection received is printed to the output window. I'm sending the string Some random data in the newConnection method to the client for testing purposes, but this is not being received by the client (the code to output the received data on the client side is inside Character::readData() method).
The value of the returnValue variable is true, and the code returns from the call to the client->waitForBytesWritten(-1) method. client->errorString() gives Unknown error, and then the message Bytes written is printed (even though, evidently, nothing is written, but I'm just using it as a status message).
Server.cpp
#include "Server.h"
Server::Server(QObject *parent) : QObject(parent)
{
server = new QTcpServer(this);
qDebug() << connect(server, SIGNAL(newConnection()), SLOT(newConnection()));
qDebug() << connect(server, SIGNAL(bytesWritten()), SLOT(bytesWritten()));
qDebug() << "Listening:" << server->listen(QHostAddress::Any, 1451);
server->waitForNewConnection(-1);
}
void Server::newConnection()
{
qDebug("Connection received");
client = server->nextPendingConnection();
client->write("Some random data\n");
bool returnValue = client->flush();
qDebug() << "Return value: " << returnValue;
qDebug() << client->waitForBytesWritten(-1);
qDebug() << "Error: " << client->errorString();
qDebug() << "Bytes written";
}
void Server::bytesWritten(qint64 bytes)
{
qDebug() << "Bytes written: " << QString::number(bytes);
}
void Server::writeData(std::string data)
{
QByteArray byteArray = QByteArray(data.c_str());
qDebug() << "Write data: " << QString::fromStdString(data);
client->write(byteArray);
}
Client.cpp
#include "Client.h"
#include "mainwindow.h"
Client::Client(QObject* parent) : QObject(parent)
{
socket = new QTcpSocket(this);
(void)QObject::connect(socket, SIGNAL(connected()), this, SLOT(connected()));
qDebug() << "Connect signal" << QObject::connect(socket, SIGNAL(readyRead()), this, SLOT(readData()));
}
bool Client::connectToHost(QString host)
{
socket->connectToHost(host, 1451);
socket->waitForConnected();
qDebug() << "Error: " << QString::number(socket->error() == QAbstractSocket::UnknownSocketError);
return true;
}
void Client::connected()
{
qDebug("Socket is connected");
qDebug() << QString::number(socket->state() == QAbstractSocket::ConnectedState);
}
void Client::readData()
{
qDebug("Read data");
QTcpSocket* sender = static_cast<QTcpSocket*>(QObject::sender());
QByteArray data = sender->readAll();
std::string character = data.toStdString();
qDebug() << "Character received: " << QString::fromStdString(character);
MainWindow::characterReceived(character);
}
I have the following question related to POCO library. My client listens the messages from our backend server using POCO library. All is well the first 50 minutes, then with the socket happens something strange and method "receiveFrame" begins to return an exception. After that, the socket does not become operational. I have made few tests the time after which I receive not operational socket is exactly 50 minutes. Also I need to note that our backend server doesn't send anything during all time. I have no idea what happens... Below is code of our Handshake and Read procedures:
void WebSocketManager::Handshake()
{
qDebug() << "WebSocketManager::Handshake";
try {
HTTPResponse response;
QString origin = Settings::Instance()->GetErPortal();
QString host = origin.remove("http://");
host = host.remove('/');
QString token = "/event/bus/ws/subscribe?auth_token=" + Settings::Instance()->token().toUtf8();
_wssession.setHost(host.toUtf8().constData());
_wssession.setPort(80);
HTTPRequest request(HTTPRequest::HTTP_GET, token.toUtf8().constData(),HTTPMessage::HTTP_1_1);
request.set("origin", origin.toUtf8().constData());
_wssock = new WebSocket(_wssession, request, response);
response.getStatus();
HTTPResponse::HTTPStatus status = response.getStatus();
qDebug() << "Handshake status is : " << status;
if(status == HTTPResponse::HTTPStatus::HTTP_SWITCHING_PROTOCOLS)
_status = true;
}
catch (std::exception &e)
{
qDebug() << "WebSocketManager::Handshake exception " << e.what();
}
}
void WebSocketManager::Read()
{
char receiveBuff[1024];
while(_status)
{
qDebug() << "WebSocketManager::Read wait data...., thread = " << QThread::currentThread();
try {
int flags=0;
int rlen=_wssock->receiveFrame(receiveBuff,1024,flags);
if(!rlen)
{
qDebug() << "WebSocketManager::Read error";
emit ConnectionFailed();
return;
}
else
{
qDebug() << "WebSocketManager::Read, len =" << rlen << ", flags = " << flags << ", data = " << receiveBuff;
ProcessBackendEvent(QString(receiveBuff));
}
}
catch (std::exception &e)
{
qDebug() << "WebSocketManager::Read exception " << e.what();
}
}
}
It seems it is bug of POCO library described here https://github.com/pocoproject/poco/issues/490
On 1.9.0 POCO library all work fine...
I would have to send Modbus request for specific data, my problem is that I have to use mobile communication, wifi, connect to a custom electronic card, which is right in Modbus RTU.
My working code connecting to the electronic board:
#include "connessione.h"
#include <QModbusTcpClient>
#include <QVariant>
#include <QModbusDataUnit>
#include <QDebug>
connessione::connessione(QObject *parent) : QObject(parent)
{
qDebug() << "here debug " << "ok";
clientX = new QModbusTcpClient();
clientX->setConnectionParameter(QModbusDevice::NetworkAddressParameter, "192.168.222.1");
clientX->setConnectionParameter(QModbusDevice::NetworkPortParameter, 5555);
if (clientX->connectDevice())
{
qDebug() << "connected: " << clientX->state();
}
else
{
qDebug() << "ERRORE" << clientX->errorString();
}
}
void connessione::clickButton(){
QModbusDataUnit readUnit(QModbusDataUnit::HoldingRegisters, 0, 1); // just read input register 40006
//qDebug() << "readUnit" << readUnit.RegisterType;
qDebug() << "readUnit" << clientX->state();
if (auto *reply = clientX->sendReadRequest(readUnit, 255)) // client id 255
{
if (!reply->isFinished())
{
// connect the finished signal of the request to your read slot
qDebug() << "connected" << reply->errorString();
connect(reply, &QModbusReply::finished, this, &connessione::readReady);
}
else
{
qDebug() << "Errore" << reply->errorString();
delete reply; // broadcast replies return immediately
}
}
else
{
qDebug() << "Errore" << reply->errorString();
// request error
}
}
void connessione::readReady()
{
QModbusReply *reply = qobject_cast<QModbusReply *>(sender());
if (!reply)
return;
if (reply->error() == QModbusDevice::NoError)
{
const QModbusDataUnit unit = reply->result();
int startAddress = unit.startAddress(); // the start address,
int value = unit.value(0); // value of the start address + 0
qDebug() << "NESSUN ERRORE" << reply->errorString();
}
else
{
qDebug() << "Errore readReady" << reply->errorString();
// reply error
}
reply->deleteLater(); // delete the reply
}
log string TCP sent:
D/libmodbusMobile.so( 8042): (null):0 ((null)): qt.modbus: (TCP
client) Sent TCP PDU: 0x0300000001 with tId: 2
this is right: 0x0300000001
But unfortunately, my electronic card, the integrated firmware I can not modify, is right with Modbus RTU, so I should change 0x0300000001 to 0x010300000001C1C2 where C1 and C2 are the checksums.
I believe that QModbusDataUnit generate buffer to send. So how to change it? Exist manual solution where I build the buffer?
how to change it and create custom send buffer like the example?
Thanks
This is Homework so just some conceptual tips woudl be nice.
At the Moment im creating a client server project, the client will send a message to the server(this part works great), but then the server sends a message back to the client and this is where I begin to have issues, I have created a separate class in QT called Connection Management in my client that deals with sending a receiving messages, this class is used by my Controller class, which handle the Application logic of all my UI Pages, now when my controller, sends a message to the server a message is sent back, atm I have it as an echo, my ConnectionManagement class handles Incomming messages with the readyRead() signal, the problem here is when someone is using my client and say press the next button, the next button slot will be called, and wait until after execution of NextButtonPressed() or w/e. until the read ready notices, there is something being sent back to it, i tried having a read i can call manually but it doesn't appear to work any suggestions?
a small bit of my code:
ConnectionManager.cpp
ConnectionManager::ConnectionManager(QObject *parent)
: QTcpServer(parent)
{
socket = new QTcpSocket(this);
connect(socket, SIGNAL(readyRead()), this, SLOT(readyread()));
connect(socket, SIGNAL(disconnected()), this, SLOT(disconnect()));
socket -> connectToHost("192.168.0.119",60000);
}
QString ConnectionManager::getMessage()
{
//sleep(1);
while (inMessage == "")
{
//my attempt at calling read() manually it will read nothing
QByteArray data = socket->readAll();
//just checkign what i am getting my server will immediately return a trivial
//string i.e "carly, santos, andrew, bob"
std::cout << data.data() << "+ 8" << std::endl;
inMessage = data;
}
return inMessage;
}
void ConnectionManager::sendMessage(QString &message)
{
socket -> write(message.toUtf8());
}
//my socket for reading whenever something is sent?
void ConnectionManager::readyread()
{
QByteArray data = socket->readAll();
inMessage = data;
std::cout << data.data() << "+ 1" << std::endl;
}
ok now my controller.cpp
void Controller::openTALogin()
{
//TODO send message to Server
QString buffer = Fill::fillBufferState("Client", "TA");
//std::cout << buffer.toUtf8().data() << std::endl;
myConnection->sendMessage(buffer); // <- this works great =)
//sleep(7);
std::cout << "1234" << std::endl;
QString in = myConnection -> getMessage(); //<- gets nothing -.-
std::cout << in.toUtf8().data() << "+ 12" << std::endl;
//TODO recieve List from server
//ForNow
QLinkedList<QString> *testList = new QLinkedList<QString>();
Fill::fillLinkedList(testList, in);
//testList -> push_front("jabba:5:hut:1");
//testList -> push_front("blind:3:mice:2");
//testList -> push_front("eat:5:day:3");
//testList -> push_front("hello:4:goodbye:4");
delete userWindow;
taLoginWindow = new TALoginWindow(this, testList);
taLoginWindow -> show();
testList -> clear();
delete(testList);
}
the message is received here after this function executes, i remember form using C-Style TCP/IP connection the read would wait until there is data to continue, but it seems for be cool with getting nothing here?
you do your send message and then immediately try to get the responce, this won't work because you need to return to the event loop before anything can be written or read
split up your Controller::openTALogin method into 2
void Controller::openTALogin()
{
//TODO send message to Server
QString buffer = Fill::fillBufferState("Client", "TA");
//std::cout << buffer.toUtf8().data() << std::endl;
myConnection->sendMessage(buffer); // <- this works great =)
}
void Controller::gotResponce(QString in)
{
std::cout << in.toUtf8().data() << "+ 12" << std::endl;
//TODO recieve List from server
//ForNow
QLinkedList<QString> *testList = new QLinkedList<QString>();
Fill::fillLinkedList(testList, in);
//testList -> push_front("jabba:5:hut:1");
//testList -> push_front("blind:3:mice:2");
//testList -> push_front("eat:5:day:3");
//testList -> push_front("hello:4:goodbye:4");
delete userWindow;
taLoginWindow = new TALoginWindow(this, testList);
taLoginWindow -> show();
testList -> clear();
delete(testList);
}
and have the second part called in your readyRead:
void ConnectionManager::readyread()
{
QByteArray data = socket->readAll();
inMessage = data;
std::cout << data.data() << "+ 1" << std::endl;
emit recievedMessage(QString(inMessage)); // using signal here
}