unsubscribe

[ Function ]

public static unsubscribe(
    requestId: number, 
    callback?: null | (
        (data: TcHmi.Server.IResultObject) => void
    )
): number | null;

Cancels an existing subscription.

Parameter

Name	Type	Description
requestId	number	The request ID of the subscription that is to be terminated.
callback [ optional ]	null, (data: TcHmi.Server.IResultObject) => void	Asynchronous callback function that is triggered when the operation was terminated.

Return value

Type	Description
number, null	The request ID as number or null in the event of an error.

	Available from version 1.10

Sample - JavaScript

var commands = [
    {
        'symbol': 'PLC1.MAIN.bTest'
    },{
        'symbol': 'PLC1.MAIN.nTest'
    }
];

var requestId = TcHmi.Server.subscribe(
    commands, 
    500, 
    function (data) {
        // ...
    }
);

setTimeout(function () {
    if (requestId === null) {
        return;
    }
    TcHmi.Server.unsubscribe(
        requestId, 
        function (data) {
            if (data.error !== TcHmi.Errors.NONE) {
                // Handle TcHmi.Server class level error here.
                return;
            }
            var response = data.response;
            if (!response || response.error !== undefined) {
                // Handle TwinCAT HMI Server response level error here.
                return;
            }

            var commands = response.commands;
            if (commands === undefined) {
                return;
            }
            var command = commands[0];
            if (command === undefined) {
                return;
            }

            if (command.error !== undefined) {
                TcHmi.Log.debugEx('Unsubscribe for subscription with request id=', requestId, ' failed.');
            } else {
                TcHmi.Log.debugEx('Unsubscribe for subscription with request id=', requestId, ' finished.');
            }
        }
    );
}, 500);