php modbus用mysql读取多个寄存器

Question

我正在尝试使用来自http://code.google.com/p/phpmodbus/的phpmodbus从modbus寄存器读取寄存器146和601

脚本成功加载第一条记录，但在第二条记录时失败 我得到的错误是：致命错误：超出最长执行时间

我的代码如下：

require_once dirname(__FILE__) . '/Phpmodbus/Phpmodbus/ModbusMaster.php';
$modbus = new ModbusMaster("10.234.6.11", "TCP");

//the sql contaions the two records 146 and 601
$sql = "SELECT num FROM `main`";
$result = mysqli_query($con,$sql);
while($row = mysqli_fetch_array($result)) {

    echo $row['num'] . "<br>";    
    $recData = $modbus->readMultipleRegisters(1, $row['num'], 1);

    //modbus status
    echo $modbus;

    //converting
    $values = array_chunk($recData, 2);
    foreach($values as $bytes) {
        echo PhpType::bytes2signedInt($bytes) . "<br>";
    }
}