Modbus TCP Client write holding registers

Damian7546

@jsulm said in Modbus TCP Client write holding registers:

@Damian7546 I'm also wondering why you use threads at all?
If you need to do something periodically then simply use QTimer.

I would like to run Client on thread and test with several clients(threads) ... how will it be with stability and read/write speed,
So how define wr_redy in *.h file ?

jsulm

@Damian7546 said in Modbus TCP Client write holding registers:

So how define wr_redy in *.h file ?

Don't define it as lambda, but a normal method.

Damian7546

@jsulm How do I do that?
When I declare my function in *.h file :
void wr_redy();

And I will create definition this function outside my run() function , I do not have acces to variables defined in run()...

jsulm

@Damian7546 If you want to connect a lambda to a signal then do it properly:

connect(this, ClientMachine1::holdRegArrayChanged, this, wr_redy);

wr_redy is NOT a member of your class, so simply do not prefix it with your class name.

Damian7546

@jsulm said in Modbus TCP Client write holding registers:

@Damian7546 If you want to connect a lambda to a signal then do it properly:
connect(this, ClientMachine1::holdRegArrayChanged, this, wr_redy);
wr_redy is NOT a member of your class, so simply do not prefix it with your class name.

Right

Damian7546

@jsulm Unfortunetly my write function still doesn't work:/

auto wr_redy = [&](){
            for(int i=0; i < m_holdRegArray.count(); i++){
                qDebug() << "count: " << i;
                wr.setValue(i, m_holdRegArray[i]);
            }
    };

The application was crash when it wr.setValue(i, m_holdRegArray[i]); is called...

jsulm

@Damian7546 said in Modbus TCP Client write holding registers:

The application was crash when

So, did you use debugger to see why it crashes?
What is wr?

Damian7546

@jsulm When I have status: "ModbusTCPClient is disconnected" my app crash when I try write registers..

jsulm

@Damian7546 Then don't write registers if there is no connection...

Damian7546

@jsulm I was wrong, sometimes app was crash when I try write value. I get message like below :

QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QObject: Cannot create children for a parent that is in a different thread.
(Parent is QModbusTcpClient(0x504f8fc), parent's thread is ClientTicketMach(0x1215a30), current thread is QThread(0x11c0b28)
QObject::startTimer: Timers cannot be started from another thread
Error Modbus TCP CLient read:  QModbusDevice::TimeoutError
QObject::killTimer: Timers cannot be stopped from another thread

jsulm

@Damian7546 As all these errors tell you: do the threading properly!

Damian7546

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Damian7546

This post is deleted!

Damian7546

@jsulm said in Modbus TCP Client write holding registers:

@Damian7546 As all these errors tell you: do the threading properly!

Can you explain me ?

jsulm

@Damian7546 Look:

QObject: Cannot create children for a parent that is in a different thread.
(Parent is QModbusTcpClient(0x504f8fc), parent's thread is ClientTicketMach(0x1215a30), current thread is QThread(0x11c0b28)

It seems like your QModbusTcpClient is used in different threads. Please analyse your code to see how you're using it.

I already mentioned in this thread that threads should only be used if really necessary.

Damian7546

This post is deleted!

Damian7546

@jsulm This connect declared in run() function:
connect(this, &ClientTicketMach::holdRegArrayChanged,wr_redy);
run wr_redy in other threadss..:/

Do you have any idea how run wr_redy in my thread by change values in holdRegArray?

Damian7546

@jsulm Now I use Modbus TCP Client without threads and everything works.