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javascripttimeupdating

Javascript code to check whether the time is updating

I was wondering if anybody can help me to write a javascript code that will check whether the time on my HMI is updating every seconds, if the time stops it should alert the user. I have a string variable called "device.string.TIME" that my HMI is reading from the PLC over modbus, the format the HMI is reading is in strings "12:00:00". This string is updating continuously (1 second) from the PLC, now when this time gets stale for 2 seconds i want to alert the user.

Solution 
  • var oldTime = 0;
function checkTime() {
   var newTime = device.string.TIME;
   if(oldTime!=0&&newTime==oldTime) {
      alert("something!");
      return;
   }
   oldTime = newTime;
   window.setTimeout(function() {
            checkTime();
   },1000)
}
    checkTime()

    1000ms = one second