php socket 处理只是来数据流，该怎样避免(好像是堵塞了)

php socket 处理只是来数据流，该怎样处理(好像是堵塞了)
需求:php接受一个硬件往8888port上发送数据，假设收到后，应socket_send函数返回“xFAx01x01xFFxAAxAAx00x01x00x00x00x00x00x01”。硬件再接收到socket_send发送的数据后，会“滴”一声，可是问题出现了。一个硬件还好，可是当多个硬件同一时候连接并同一时候发送数据时，会出现硬件不能连续的回应（即发出“滴”的声音），也就是说能连续发出“滴”声后，便不在响了，大概几秒钟后。又開始响应了，过一会又不行了。几个连接上的硬件都是这样。我已经用了非堵塞模式，还是会这样，求解决方法，以下贴出代码

PHP code

<?php
error_reporting(E_ALL);
set_time_limit(0);
ini_set("allow_call_time_pass_reference",true);

//监听port
$PORT = 8888;
//最大连接池
$MAX_USERS = 50;
//创建监听port
//$sock = socket_create_listen($PORT);


$commonProtocol = getprotobyname("tcp");
$sock = socket_create(AF_INET, SOCK_STREAM, $commonProtocol);
@socket_bind($sock, '192.168.1.112
@socket_listen($sock);




if (!$sock)
{
    exit(1);
}
//不堵塞
socket_set_nonblock($sock);

$connections = array();
$input = array();
$close = array();

while (true)
{
    //sleep(3);
    $readfds = array_merge($connections, array($sock));
    $writefds = array();

    //选择一个连接。获取读、写连接通道
    if (socket_select($readfds, $writefds, $e = null, $t=60))
    {
        foreach ($readfds as $rfd)
        {
            //假设是当前服务端的监听连接
            if ($rfd == $sock)
            {
                //接受client连接
                $newconn = socket_accept($sock);
                $i = (int)$newconn;
                $reject = '';
                if (count($connections) >= $MAX_USERS)
                {
                    $reject = "Server full. Try again later.
";                   
                }                
                //将当前client连接放如socket_select选择
                $connections[$i] = $newconn;
                //输入的连接资源缓存容器
                $writefds[$i] = $newconn;               
                //连接不正常
                if ($reject)
                {                  
                    $close[$i] = true;
                }
                else
                {
                    echo "Welcome to the PHP Chat Server!
";                  
                }               
                //初始化当前连接读取内容的缓存容器
                $input[$i] = "";
                continue;
            }
            //client连接
            $i = (int)$rfd;
            //读取
            $tmp = @socket_read($rfd, 14, PHP_NORMAL_READ);
            if (!$tmp)
            {
                //读取不到内容              
                print "connection closed on socket $i
";
                close($i);
                continue;
            }
            $input[$i] .= $tmp;
            $tmp = substr($input[$i], -1);
            /*if ($tmp != "
" && $tmp != "
")
            {
                // no end of line, more data coming
                continue;
            }*/
            $line = trim($input[$i]);
            $input[$i] = "";
            echo 'Client >>'.$line."
";
            
            
            
            
            socket_getpeername($connections[$i],&$remoteIP,&$remotePort);
echo $remoteIP."
";
echo $remotePort."
";
//$data=str_split($buffer);
//print_r($data);
$str="xFAx01x01xFFxAAxAAx00x01x00x00x00x00x00x01";
 socket_send($connections[$i],$str,strlen($str),0);
            
            
            
            
            
            
        }
        foreach ($writefds as $wfd)
        {
            $i = (int)$wfd;
            $w = socket_write($wfd, "hello");
        }
    }   
}

function close($i)
{
    global $connections, $input, $close;
    socket_shutdown($connections[$i]);
    socket_close($connections[$i]);
    unset($connections[$i]);
    unset($input[$i]);   
    unset($close[$i]);
}
?>