How to use AUX Functions

This guide describes how to use ISOBUS AUX-N Functions (Auxiliary Function Type 2) in implement application.

The ISOBUS Auxiliary control is defined in the ISO 11783-6 Annex J.

It is recommended to have knowledge on how to build basic ISOBUS VT project before adding AUX-N Functions. See also Using ISOBUS.

General information

Auxiliary control (AUX) allows the operator to control specific functions independent of the VT interface,

as long as the Auxiliary Inputs and Auxiliary Functions maintain the connection between them and the VT.

Auxiliary Inputs (keys, switches, dials, knobs, sliders), provided by one or more Working Sets (or the VT),

are active at all times after being assigned to an Auxiliary Function―independent of active visible Data Mask and visible Soft Key Mask of the VT.

These inputs are assigned to Auxiliary Functions (i.e. raise/lower, start/stop, set position) and are also provided by one or more Working Sets (or the VT).

The operator can assign the inputs to the functions using a proprietary auxiliary assignment screen provided by the VT.

Once an Auxiliary Input has been assigned to an Auxiliary Function by the VT, the operator is then able to control the function independent of the active Working Set on the VT.

For more information, see ISO 11783-6 Annex J.

Epec ISOBUS VT library implements the AUX-N Function handling which:

• Handles communication between ECU - AUX Input device

• Handles AUX Function assignment commands between VT - ECU

• Handles AUX Function preferred assignment command between VT - ECU

• Updates AUX Function data to application

See also ISOBUS_AUX_FunctionHandler (FB)

Preferred assignments will be stored in the ECU's nonvolatile memory and loaded to the VT after the client is connected.

This allows automatic function assignment, for example, when the system is restarted.

Application requirements

The AUX Function Handler is automatically added to the code template when AUX-N is selected in use.

The following is required by the application to use AUX-N Functions:

• Initialize ISOBUS VT in MultiTool Creator

• Set "AUX-N Functions in use" setting TRUE in MultiTool Creator

• Add AUX-N Functions to the object pool in ISO-Designer

• Initialize VT preferred instance and wait delay

• Initialize address claim server monitoring time

• Initialize preferred assignments to the AUX Function Handler

• Trigger preferred assignment loading using ISOBUS_AUX_LoadPreferred (FUN)

• Save preferred assignments to nonvolatile memory

• Re-trigger preferred assignment loading if preferred input is detected during operational stage

• Use the AUX-N Functions in application

Example implementation is described below.

• Example uses CANopen OD to save preferred assignments in nonvolatile memory.

• Example has CANopen defined in CAN1 and ISOBUS in CAN2.

Adding AUX-N Functions

AUX-N Functions are added to the VT object pool using ISO-Designer.

AUX-Function object is added for each functionality that is implemented by application.

1. Open ISO-Designer project

2. Check that VT Level 3 (VT version 3) is selected

3. Add AUX-Function object

4. Define the AUX Function properties

5. Design the AUX Function Designator symbol

Object pool has a list of AUX Function 2 objects.

For example:

AUX Function has following properties:

• AUX Function designator size is same than used with softkeys

• Function type

• Defines which type of input function is used for

• The AUX Function can only be assigned to the same type of input

• Standard supports types 0 - 14 which includes different boolean and analog functions and combinations of those

• Critical control

• If setting is not selected, the AUX Function can be used with any AUX Input device of same type

• If setting is selected, the AUX Function can only be used with the AUX Input device which supports it

• Assignment lock

• If setting is not selected, the AUX Function can be assigned by operator manually or by preferred assignment

• If setting is selected, the AUX Function can only be assigned by preferred assignment

• Single Assignment

• If setting is not selected, the AUX Function can be assigned to same input with other AUX Functions (multiple assignment)

• If setting is selected, other AUX Functions cannot be assigned to same input with this AUX Function

• Enable export setting is not needed, the AUX objects are used from the same object pool binary than VT

AUX Function designator symbol needs to be defined in ISO-Designer.

For example:

The symbol is shown for example in VT AUX assignment screen.

Defining OD variables for preferred assignments

Each AUX Function object has preferred assignment which needs to be saved.

Preferred assignment consists of:

1. Function object ID (WORD)

2. Input object ID (WORD)

3. Model identification (WORD)

4. Input name (ARRAY [0...7] OF BYTE)

For the application logic boolean flag is also saved to OD for each AUX Function.

This is used to know if preferred assignment has been saved.

1. Define OD index 2200h, index type SingleVariables, data type WORD.

• Define one subindex per AUX Function for function object IDs

2. Define OD index 2201h, index type SingleVariables, data type WORD.

• Define one subindex per AUX Function for input object IDs

3. Define OD index 2202h, index type SingleVariables, data type WORD.

• Define one subindex per AUX Function for model identifications

4. Define OD index 2203h, index type SingleVariables, data type BOOL.

• Define one subindex per AUX Function for save flags

5. Define OD index 2204h...22XXh, index type ArrayOf [0..7], data type BYTE.

• Define one OD index per AUX Function for input names

AUX-N code template

The code template for AUX-N is updated in the same way than with ISOBUS VT using Edit > Macros > Import MultiTool and Import ISOBUS.

The AUX Function Handler is automatically added to code template and executed.

For AUX-N, there is new ISOBUS VT > ISOBUS CANx > IsobusVTAuxiliaryControl Global Variable List generated.

The Global variable list includes:

• AUX Function Handler instance and variables for error and state

• AUX Function data objects for application use, which contains the enable variable and function type specific scaled data

• AUX Function configuration table which is used by the handler. This array also contains the preferred assignments

Initializing VT preferred instance and wait delay

Application shall set the VT preferred instance and wait delay. See example in How to set VT preferred instance and move to another VT.

If secondary VT is the preferred instance, the VT client will wait for the primary VT for preferred wait delay (when AUX Functions are in use)

If primary VT is not found, the UI will be loaded to secondary VT but the AUX Functions are not usable in this case

Initializing address claim server monitoring time

Set 500ms monitoring time delay for address claim server.

This is related to conformance tests performed when AUX Functions are in use.

Delay is used to detect if address claim device has disappeared from ISOBUS when new address claim request is sent and previously present device does not respond anymore.

Initializing preferred assignments

Application needs to read the saved preferred assignments from OD variables and initialize the structs in the AUX Function configuration array.

The following example checks if the preferred assignment has been saved to OD.

If the preferred assignment is saved, then the values are updated to the AUX Function configuration array.

Application also needs to set LoadPreferredAssignment flag to TRUE on those AUX Functions which will be loaded as preferred assignments to VT.

Example for two AUX Functions. This needs to be done for each AUX Function.

This code is executed in the next step when the preferred assignment loading is done.

Loading preferred assignments

The preferred assignments needs to be loaded to the VT before manual assignment can be done.

This can be done automatically, for example, after VT client has connected to the server.

Application UI can also implement manual loading of preferred assignments if necessary.

The preferred assignment also needs to be loaded again if preferred input is detected after initial loading has been done.

Library provides output o_PreferredInputDetected for re-triggering preferred assignments.

If all LoadPreferredAssignment flags are FALSE, then the library will load the preferred assignment list as empty.

The following is an example code for automatically triggering preferred assignment loading:

once after VT object pool has been loaded

if preferred input is detected

Saving preferred assignments

When AUX Function assignment is done, VT will indicate if the assignment should be saved as a preferred assignment.

AUX Function Handler will set the SavePreferredAssignment TRUE when the application needs to save the preferred assignment.

The following example is for saving two AUX Functions. Each AUX Function has an individual save flag which is checked.

The following example executes the save action and triggers the OD saving.

Resetting preferred assignments

Application can optionally implement preferred assignment parameter resetting.

The following example resets the AUX Function configuration array's preferred assignments to default values.

The save flags are also reset in OD variables.

The following example executes the reset and triggers the OD saving.

Using AUX-N Functions

Each of the AUX Functions hasa global variable containing an Enable flag and scaled values / states specific to the function type.

The global variable is G_ISOBUS_CAN<X>_AUX_<AUX_Function_Name> where X is the ISOBUS CAN number.

The variable's type is ISOBUS_AUX_FunctionDataType<X> where X is the function type number.

Structs are defined in ISOBUS VT library.

See also

• ISOBUS_AUX_FunctionHandler (FB)

• ISOBUS_AUX_LoadPreferred (FUN)

• ISOBUS Conformance Guide

• Using ISOBUS