Please download the sample and try! There are 2 projects in the solution. 1 PLC project and another HMI project. The status is displayed from the PLC to the HMI.

The JavaScript code:

// Keep these lines for a best effort IntelliSense of Visual Studio 2017 and higher.
/// <reference path="../../Packages/Beckhoff.TwinCAT.HMI.Framework.12.742.0/runtimes/native1.12-tchmi/TcHmi.d.ts" />
(function (TcHmi) {
    var Functions;
    (function (Functions) {
        var MyNamespace;
        (function (MyNamespace) {
            function JSGetValveImagePath(IsClosed, DeviceType) {
                var returnamenpath = '';
                switch (DeviceType) {
                    case 0:
                        if (IsClosed == true) {
                            returnamenpath = 'Images/pipehor_closed.svg';
                        }
                        else {
                            returnamenpath = 'Images/pipehor_open.svg';
                        }

                        break;
                    case 1:
                        if (IsClosed == true) {
                            returnamenpath = 'Images/pipever_closed.svg';
                        }
                        else {
                            returnamenpath = 'Images/pipever_open.svg';
                        }
                        break;
                    case 2:
                        if (IsClosed == true) {
                            returnamenpath = 'Images/pipever_closed.svg';
                        }
                        else {
                            returnamenpath = 'Images/pipever_open.svg';
                        }
                        break;
                    case 3:
                        if (IsClosed == true) {
                            returnamenpath = 'Images/pipehor_closed.svg';
                        }
                        else {
                            returnamenpath = 'Images/pipehor_open.svg';
                        }
                        break;
                    default:
                        break;
                }
                return returnamenpath;
            }
            MyNamespace.JSGetValveImagePath = JSGetValveImagePath;
        })(MyNamespace = Functions.MyNamespace || (Functions.MyNamespace = {}));
        Functions.registerFunctionEx('JSGetValveImagePath', 'TcHmi.Functions.MyNamespace', MyNamespace.JSGetValveImagePath);
    })(Functions = TcHmi.Functions || (TcHmi.Functions = {}));
})(TcHmi);            
           

The PLC Code:

//Function block header
FUNCTION_BLOCK FN_DEVICES
VAR_INPUT
	Enabled : BOOL; 
	DeviceType : SINT;
END_VAR
VAR_OUTPUT
	Is_Closed : BOOL;
	DeviceName : T_MaxString;
END_VAR
VAR
	myTimer : TON;
	counter : UINT := 0;
	timeInterval : TIME;
END_VAR

//Function block body
(* 
If the device is enabled  then the program generate IsClosed to false from true and vice versa to simulate UI and the device.

Device name and their type
Name 			type
Lock  			0    ->   Every 200 miliseconds interval changes the status
Thermometer		1    ->   Not valid as there is no IsClosed variable
Water Valve 	        2    ->   Every 400 miliseconds interval changes the status
MainDoor		3    ->   Every 500 miliseconds interval changes the status
*)

	CASE DeviceType OF
		0:
		timeInterval := T#200MS;
		DeviceName := "Door Lock";

		1:
		timeInterval := T#300MS;
		DeviceName := "Thermometer";		
		;
		
		2:
		timeInterval := T#400MS;
		DeviceName := "Water Valve";
		
		3:
		timeInterval := T#500MS;
		DeviceName := "MainDoor";		
	END_CASE
	
myTimer(IN:= Enabled, PT:= timeInterval);
IF myTimer.Q = TRUE  THEN
	myTimer(IN:= FALSE);
	IF Is_Closed = TRUE THEN
			Is_Closed := FALSE;
		ELSE			
			Is_Closed := TRUE;
	END_IF
END_IF