This project deals with an implementation of the basic functionality of the Modbus TCP and UDP based protocol using PHP. It's a copy of the releases from the project page over at Google Code with composer support added.
The upstream library had trouble reading data from SMA solar inverters via modbus. This was fixed by explicitly reading the length-field of the transmitted data and then waiting for the specified amount of data.
Warning! This library was NOT tested with a UDP modbus server and could behave wrong!
- Modbus master
- FC1 - Read coils
- FC2 - Read input discretes
- FC3 - Read holding registers
- FC4 - Read holding input registers
- FC5 - Write single coil
- FC6 - Write single register
- FC15 - Write multiple coils
- FC16 - Write multiple registers
- FC22 - Mask Write register
- FC23 - Read/Write multiple registers
// Modbus master UDP
$modbus = new ModbusMaster("192.168.1.1", "UDP");
// Read multiple registers
try {
$recData = $modbus->readMultipleRegisters(0, 12288, 5);
}
catch (Exception $e) {
// Print error information if any
echo $modbus;
echo $e;
exit;
}
// Print data in string format
echo PhpType::bytes2string($recData);
For more see documentation or FAQ.