How to implement Modbus TCP data recording and analysis through PHP

How to implement Modbus TCP data recording and analysis through PHP

Modbus is a communication protocol that is widely used in the field of industrial automation. Modbus TCP is a variant of the Modbus protocol that transmits over Ethernet, providing higher speed and reliability. This article will introduce how to use PHP language to implement Modbus TCP data recording and analysis.

1. Install the PHP Modbus extension
First, we need to install the PHP Modbus extension. You can install it with the following command:

$ pecl install modbus

After installation, add the following line in the php.ini file:

extension=modbus.so

Save and restart PHP.

2. Establish Modbus connection
Using the PHP Modbus extension, we can easily establish a connection with Modbus devices. First, we need to create a Modbus master using the ModbusMaster class.

require_once('ModbusMaster.php');

$ip = '192.168.1.100'; // IP address of the Modbus device
$port = 502; //Port number of the Modbus device

$modbus = new ModbusMaster($ip, $port);
?>

3. Read the value of the Modbus register
Next, we can use the readMultipleRegisters method in the ModbusMaster class to read the value of the register in the Modbus device.

$slaveId = 1; // Slave address
$startAddress = 0; // Starting address
$numberOfRegisters = 10; // Need to read Number of registers

$data = $modbus->readMultipleRegisters($slaveId, $startAddress, $numberOfRegisters);

var_dump($data); //Print the read register value
?>

4. Write the value of the Modbus register
We can also use the writeSingleRegister method in the ModbusMaster class to write the value of the register in the Modbus device.

$slaveId = 1; // Slave address
$registerAddress = 0; // Register address
$value = 123; // Value to be written

$modbus->writeSingleRegister($slaveId, $registerAddress, $value);
?>

5. Data recording and analysis
Through the above steps, we have The connection to the Modbus device was successfully established and the value of the register was able to be read and written. Next, we can use PHP's file operation functions to implement data recording and analysis.

$file = 'data.txt'; // Data record file

// Read historical data in the file
$historyData = [] ;
if (file_exists($file)) {

}
$average = $total / $count ;

echo 'Historical data recording completed. ' . PHP_EOL;
echo 'Total number of historical data:' . $count . 'Bar' . PHP_EOL;
echo 'Average of historical data:' . $average . PHP_EOL;
?>

6. Summary
Through the above steps, we have successfully implemented Modbus TCP data recording and analysis using PHP language. By establishing a Modbus connection, reading and writing register values, and using file operation functions for data recording and analysis, we can easily monitor and control the data of Modbus devices. Hope this article can be helpful to you!

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