I do the TCP server, to write 01, 40009, I can now use QModbusServer setdata values, but you can't get a message on the client side using the simulator,

 
//if there is no defined modbus serial port, direct return 
if (! ModbusDevice) 
{
STD: : cout & lt; <"The Modbus communication failure, please check whether the configuration is correct!" return; 
} 
QString str2="9 c490001020001"; 
For (int I=0; i <10; I++) 
{
Int j=2 * I; 
QString str1=str2. Mid (j, 2); 
bool ok; 
Quint16 hex=str1. ToInt (& amp; Ok, 16); 
//qDebug (" % d ", hex); 
Ok=modbusDevice - & gt; SetData (QModbusDataUnit: : HoldingRegisters, I, hex); 
//STD: : cout & lt; 
}