php-modbus/examples/example_fc23.php

<?php

use PHPModbus\ModbusMaster;

// Create Modbus object
$modbus = new ModbusMaster("192.192.15.51", "UDP");

// Data to be writen
$data = array(10, -1000, 2000, 3.0);
$dataTypes = array("WORD", "INT", "DINT", "REAL");

try {
	// FC23
	$recData = $modbus->readWriteRegisters(0, 12288, 6, 12288, $data, $dataTypes);
} catch (Exception $e) {
	// Print error information if any
	echo $modbus;
	echo $e;
	exit;
}

// Print status information
echo "</br>Status:</br>" . $modbus;

// Print read data
echo "</br>Data:</br>";
print_r($recData);
echo "</br>";