Arinc 661 standard
The Arinc 661 standard defines the interface standard between the user application (UA: User application) and the Cockpit display system (CDS: Cockpit DisplaySystem) , which realizes the loose coupling of display and control. Compared with the centralized integrated display control system, ARINC 661 architecture has better reusability and maintainability, can be used for different purposes and different models, Saves Development and verification time, and reduces development and maintenance cost. The system of Arinc 661 standard includes three entities: CDS, UA and the communication protocol between them. The communication protocol includes two parts: definition phase and operation phase. The system architecture for the Arinc 661 standard is shown in figure:　　

Arinc 661 Standard System Architecture

Arinc 661 has three basic concepts
　The first is CDS, which is commonly referred to as Arinc 661 Server in engineering applications because the Arinc 661 standard allows one CDS to render multiple UA required displays. Arinc 661 introduces the concept of Display hierarchy in CDS, including Display Unit, Window, Layer and Widget, to make it easy for the system to manage different layers of entities to form a tree structure. Display Unit is the topmost entity in the CDS and can be made up of multiple Window entities, neither CDS nor UA can dynamically control the properties of the Display Unit entity. The Window is a rectangular area of Display Unit with clipping capabilities that can not be resized at run time and can not be overlapped between multiple windows. Layer is the topmost entity that can be seen by a UA IN CDS. Multiple layers make up the Window, and a UA controls multiple layers. CDS manage Layer visibility, activity, and priority based on UA requests and configuration information. The Widget is the basic unit of the interface defined in the ARINC 661 specification. To increase the flexibility of the application, ARINC 661 defines only the Widget definition phase and runtime interface, and does not constrain the specific implementation of each Widget, such as the Look & feel attribute.

　The second basic concept of Arinc 661 is UA. The development of UA depends on the specific application requirements. The Arinc 661 specification defines only the interface between UA and CDS communication. In Arinc 661 system architecture, because UA and CDS are separated, UA software is divided into logic processing module and graphics driver Module, and graphics driver module is responsible for CDS display content update. UA can control requests for Layer entities and Widget entities managed by CDS through a runtime protocol, and CDS can decide whether to respond to specific UA requests based on configuration and status information.

The third concept of Arinc 661 is communication protocol. In order to increase the adaptability of the specification, the Arinc 661 standard does not limit the specific physical channel, but only gives the application layer protocol of UAs and CDS communication. Application layer protocol can be divided into two phases: definition phase and runtime phase.

(1)Define the phase protocol

CDS establishes an internal entity structure by resolving the Definition File (DF: Definition File) during the Definition phase. The DF file is made up of Picture, Symbol, and Layer.

(2) run-time protocol

Ua controls the layers and content it owns through a run-time protocol and processes event information sent by the CDS. UA uniquely identifies a Widget in a CDS with UA [ ID ][ LayerID ][ WidgetlD ] and controls it by the Widget interface. CDS will display the Layer based on the updated Widget properties.

So to summarize the ARINC 661 Standard:

The Arinc 661 standard is intended to standardize the CDS (Cockpit Display System) , as well as communications between the CDS  and User Applications, which manage the functionality of aircraft avionics. The definitions for the graphical user interface of CDS are all included in the binary DF (Definition File) File.

The CDS software system consists of a graphical user interface kernel that, during initialization, creates a hierarchy of graphical user interface, as defined in the DF file, this approach avoids the recompilation that would result from changing the graphical user interface definition.

CDS provides logic to the graphical display system through a stand-alone UA (User Application) program. The ARINC 661 runtime protocol defines the communication interface between CDS and UA. The update data request is sent to the CDS via the event generated by the interaction with UA. The final display on a CDS consists of components from a limited set of components known as a widget library.

Brief introduction of VAPS XT ARINC 661

VAPS XT is the industry’s leading software tool for developing embedded graphics displays.

VAPS XT ARINC 661 provides a solution to develop a display system that meets the Arinc 661 standard. The VAPS XT Arinc 661 module is the HMI tool for customizing the Arinc 661 Widget.

VAPS XT ARINC 661 offers the following features:

　　● Arinc 661 widget available;

　　● Support the development of Arinc 661 compliant widgets;

　　● Support for widget extensions based on the Arinc 661 Standard;

　　● Create a CDS application using Arinc 661 widget;

　　●Generating Binary DF (Definition File) File based on Arinc 661 Standard;

　　● The CDS Code is generated by VAPS XT Code Ngen, and the executable program is compiled

　　● Create UA program through VAPS XT’s code framework and help documentation;

　　●Integration with UA Square tool to test CDS interface logic and develop UA programs;

Services to be provided by Saida

Custom development of CDS and UA applications using the VAPS XT Arinc 661 module includes the following services:

　　● Custom expanded widgets based on the Arinc 661 Standard;

　　● Customizing the Widget library according to the user’s visual needs;

　　● Create a CDS application using Arinc 661 Widget;

　　● Custom development of UA (User Application) programs;

　　● Arinc 661 Widget Chinese;

ARINC 661 typical controls:
                    Serial number             Control Name                                         Function and purpose description

                               1                       CursorPosOverlay control                      The current cursor coordinate value is sent to the UA program as an event parameter

                               2                       GPLEPOLAR control                               Used to define a polar coordinate line

                               3                      TABBEDPANEL control                            Is a panel control with a select button

                               4                      TabbedPanelGroup control group          Combines multiple panel controls that allow the UA or operator to display one of the panels through a select button

                               5                       Togglebutton control                             Is A two-state button with text that notifies the current state of UA using this event when the state of the control changes

                               6                       PROXYBUTTON control                          This control causes the physical buttons in the CDS to point to a selection event for any Widget that has a selection event

                               7                       WatchdogContainer control                   This control is used to ensure that a set of parameters can be refreshed at a specified frequency. If the timer fails to refresh at the specified frequency of 8, the                                                                                                                              CDS sends an event to the UA, and a predefined child widget is automatically displayed to indicate the failure status.

                               8                       CURSORREF control                                This control defines the location coordinates on the screen or on the map, which can be used with the A661 command

                               9                       CursorOver control                                 This control is similar to a ActiveArea that produces an immediate event as the cursor moves in and out of the active area of the Widget

                              10                      FocusLink control                                    This widget defines a sequence of nextfocusedwidgets that belong to different layers (layer) 

                              11                      External source control                           The function of this control is to specify that external input is displayed in a specific area of the CDS. For example, an external input might be a video signal or                                                                                                                              an  image. Note that if UA wants to display a video input signal on a CDS, the CDS must have the ability to process the video input.

Completed SINICIZED ARINC 661 controls:
1. A661_Label

2. A661_LabelComplex

The left prompt represents the property to be set on the string, the middle portion is the string content with the escape character, and the final display is on the right.

3. A661_PushButton

4. A661_ToggleButton

                A661 check status

              A661 unchecked status
5. A661_CheckButton

6. A661_Symbol

Arinc 661 display control application case.

Below is a CDS application developed using VAPS XT 661.

Navigation screen

Send Reference Picture

Category: Electronic System Simulation