How is it possible to enforce acknowledge of a Multiinstance alarm?

Acknowledge of a Multiinstance alarm in WinCC OA is only possible when the same alarm exists in a connected device. Every acknowledge message in WinCC OA to an alarm from a disconnected device returns a FALSE from isAckable().
This is a security functionality to prevent the system from inconsistencies.

But there could be some exception where it is necessary to enforce the acknowledge message of a Multiinstance alarm even if the device is not connected with the WinCC OA system.
In this case it is necessary to trigger an alertSet() at the _alert_hdl.._event attribute with value 4 (DPATTR_ALERTEVENT_SINGLE_ACK) at the same time where the come or went event occurred.
It is necessary to implement this alertSet() functionality in an own CTRL-Script to acknowledge the pending alarm. Below there is an example code with a function that needs two input parameters:

1.    name of the data point with the pending alarm
2.    System name of the data point

ackAlert(string dpName, string systemName)
{
  string sqlAlert;
  dyn_dyn_anytype tab;
  time alertTimeCame, alertTimeGone;
  string dpeAlert;
  time ackTime;
  bool direction;
  int indexCame, indexGone;
 

  sqlAlert = "SELECT ALERT  '_alert_hdl.._came_time', '_alert_hdl.._gone_time', '_alert_hdl.._ack_time', '_alert_hdl.._direction', '_alert_hdl.._came_time_idx', '_alert_hdl.._gone_time_idx' FROM '" + dpName + "' REMOTE '" + systemName + "'";
  dpQuery(sqlAlert, tab);
 
  for(int i = 2; i<=dynlen(tab); i++)
  {
    ackTime = tab[i][5];
    if (ackTime != 0)
    {
      //nothing to do
      continue;
    }

    direction = tab[i][6];  //check for alarm direction 1: CAME; 2: WENT
    indexCame = tab[i][7];  //readIndex Came Alarm   
    indexGone = tab[i][8];  //readIndex Went Alarm
   
    dpeAlert = tab[i][1];
    dpeAlert = strltrim( dpeAlert, dpSubStr(dpeAlert, DPSUB_SYS_DP));
   
    alertTimeCame = tab[i][3];
    alertTimeGone = tab[i][4];

    if(direction)
    {
      DebugTN("execute alertSet Came: ", alertTimeCame, indexCame, systemName + dpName + dpeAlert + ":_alert_hdl.._event", DPATTR_ALERTEVENT_SINGLE_ACK);
      alertSet(alertTimeCame, indexCame, systemName + dpName + dpeAlert + ":_alert_hdl.._event", DPATTR_ALERTEVENT_SINGLE_ACK);      
    }
    else
    {
      DebugTN("execute alertSet Went: ", alertTimeGone, indexGone, systemName + dpName + dpeAlert + ":_alert_hdl.._event", DPATTR_ALERTEVENT_SINGLE_ACK);
      alertSet(alertTimeGone, indexGone, systemName + dpName + dpeAlert + ":_alert_hdl.._event", DPATTR_ALERTEVENT_SINGLE_ACK);      
    }
  }
}