timeout to prevent blocked process due to serial interface not receiving any data

config.json

@@ -2,5 +2,6 @@
   "device": "/dev/serial/by-id/usb-VictronEnergy_BV_VE_Direct_cable_VEAWDESA-if00-port0",
   "database": "VEDirect.db",
   "logfile": "VEDirect.log",
-  "loglevel": "off"
+  "loglevel": "off",
+  "timeout": 30
 }

worker.php

@@ -105,7 +105,8 @@
       $bytesToRead = $config->bytesToRead;
     writeLog("Reading $bytesToRead Byte from VE.Direct interface\r\n", 3);
     $dataStream = "";
-    while(strlen($dataStream) < $bytesToRead)
+    $startTime = time();
+    while(strlen($dataStream) < $bytesToRead && time() < $startTime + $config->timeout)
       $dataStream .= dio_read($VEinterface, $bytesToRead);
     dio_close($VEinterface);
     writeLog($dataStream . "\r\n\r\n", 4);