i4SCADA Knowledge Base

i4SCADA Client-side Signals

Abstract

Interested in maintaining projects with temporary signal values? Check our article on Client-Side Signals and their usage in i4SCADA SmartEditor application.

The Client-side Signals are extensions to the regular signal functionality allowing the user to subscribe and write signal values that exist only temporary inside the client session.

These signals have multiple purposes, from simple things such as supporting state switching, based on client actions (ex. going in/out of a “selected” state when clicking on a button) to more complex scenarios:

  • Multiplexing/demultiplexing array signal values

  • Providing aggregated values as signals (ex. average/min/max value of log values over a certain time window)

  • Providing client-side scripting (client vchannel functionality)

Given the fact that Client-side Signals only exist in the client application and have a lifetime that is directly related to the session lifetime, there is no security concept around them. Client-side Signals can be written or read from any component. 

The Client-side Signals are regular signals that go through the standard client connector, but are not processed through the server-side. they can be used in any component that uses signals and are a form of inter-component communication.

Client-side signals are identified by the case sensitive prefix: "local://". When the connector is requested such a signal, will be registered internally but it will not include the list of signals that are registered with the server.

Client-side_signals.jpg

Client-side Signals

Tip

For a better understanding of the Client-side Signals, visit our tutorials here.