User Defined Instruction

Mnemonic (Keyboard Shortcut) = UDI

Purpose

UDI functions are similar to function blocks in other programming environments; allowing users to define custom instructions tailored to their specific automation needs. These instructions help streamline programming by encapsulating commonly used logic into reusable, self-contained modules.

Instruction Parameters

Parameter	Parameter Type	Requirements	Description
Enable	Ladder Input	Must Have	Level-driven. When Enable is ON, the instruction will operate every scan. When Enable is OFF, the instruction is not solved and its Outputs are not updated.
UDI Definition	Dropdown Selection	Must Have	A UDI definition must be created in the UDI Management panel for this instruction. Once UDI definitions have been created, they can be selected in this field.
Name	Assigned from UDI definition editor window	Must Have	Allows the user to give a unique name (maximum 32 characters) to each UDI instruction instance for easier reference. *See Note 1 below
Parameters
Parameter Name	Assigned from UDI definition editor window	Dependent on UDI configuration	Displays the parameter name (defined in the UDI Definition Editor panel).
Type	Assigned from UDI definition editor window	Dependent on UDI configuration	Indicates the parameter data type (defined in the UDI Definition Editor panel).
Columns	Assigned from UDI definition editor window	Dependent on UDI configuration	Indicates the number of columns defined for an array parameter (defined in the UDI Definition Editor panel).
Num Chars	Assigned from UDI definition editor window	Dependent on UDI configuration	Indicates the number of characters defined for string parameters (defined in the UDI Definition Editor panel).
Default Input Value	Assigned from UDI definition editor window	Dependent on UDI configuration	Indicates the default beginning value (defined in the UDI Definition Editor panel) of a parameter when the UDI is executed, if it does not have a tag assignment. This only applies to parameters with Local, In or In/Out scope. *See Note 2 below.
Scope	Assigned from UDI definition editor window	Dependent on UDI configuration	Indicates how the parameter is used (defined in the UDI Definition Editor panel). Possiblescope selections are In, Out, In/Out, and Local.
Assignment Required	Assigned from UDI definition editor window	Dependent on UDI configuration	Indicates whether a Tag or value must be assigned to the parameter (defined in the UDI Definition Editor panel).
Comment	Assigned from UDI definition editor window	Dependent on UDI configuration	Use this field to add Comments associated with the parameter.
Tag	User Selectable	Must Have/Optional	This field allows the user to assign Tags or static values for the UDI parameters. If a parameter requires assignment, then a Tag or static value must be entered in this field.
Use Structure	Selectable Option	Optional	Enables the use of Structure for elements of the chosen UDI definition. Select from dropdown list of available structure names or enter name to create a new structure.
Devices
Name	Assigned from UDI definition editor window	Dependent on UDI definition	Indicates the name of the device (defined in the UDI Definition Editor Window).
Device	Assigned from UDI definition editor window	Dependent on UDI definition	Indicates the device definition assigned (defined in the UDI Definition Editor Window).
Device Type	Assigned from UDI definition editor window	Dependent on UDI definition	Indicates the specific type of device assigned (defined in the UDI Definition Editor Window). Not all devices will have a Device Type defined.
Configured Device	User Selectable	Dependent on UDI definition	This field allows the user to choose from the list of available devices that have been defined in the project Hardware Configuration that matches the UDI device..

Note 1: Can contain only a-z, A-Z, 0-9, hyphens, underscores, and spaces.

Note 2: Default value is only available if not marked as assignment required.

Accessing UDI Instruction

The User Defined Instruction (UDI) is located on the Instruction Panel under the Program Control section.

Instruction Configuration

When User Defined Instruction is selected the window shown below opens.

Parameter Configuration Table

File Read Instruction

(UDI)

Notes

* or or These icons indicate to use 1D and/or 2D Array data types as indicated in Data Type column.

UDI Definition

Before using this instruction, the user needs to create a UDI definition in the UDI Management panel. After that, select a UDI definition in this field.

Name

Give a unique name (maximum 32 characters) to each UDI instruction instance.

Parameters

Parameters displays the list of UDI parameters defined with Assignment Required and or Visible checked in the definition.

Devices

Allow users to choose which UDI Device to associate with a Hardware Configuration Device in the project.

Name

Displays the parameter name.

Type

Indicates the parameter data type.

Cols

Indicates the number of columns defined for an array parameter.

Chars

Indicates the number of characters defined for string parameters

Default Input Value

Indicates the default beginning value of a parameter when the UDI is executed, if it does not have a tag assignment. This only applies to parameters with In, In/Out, and Local scopes.

*See note 2 above

Scope

Indicates how the parameter is used. Possible scopes are In, Out, In/Out, and Local.

Assignment Required

Indicates whether a Tag or value must be assigned to the parameter.

Comment

Use this field to add comments associated with the parameter.

Tag

This field allows the user to assign Global Tags or Constant Values for the UDI parameters. If a parameter requires assignment, than a Global Tag or Constant value must be entered in this field.

Use Structure

Enables the use of Structure for elements of the chosen UDI definition.

Name

Indicates the name of the device.

Device

Indicates the device definition assigned.

Device Type

Indicates the specific type of device assigned. Not all devices will have a Device Type defined.

Configured Device

This field allows the user to choose from the list of available devices that have been defined in the project Hardware Configuration that match the UDI device.

User Defined Instruction

Mnemonic (Keyboard Shortcut) = UDI

Purpose

Instruction Parameters

Accessing UDI Instruction

Instruction Configuration

File Read Instruction

(UDI)

Notes

Example of creating / instantiating a UDI that requires a device assignment:

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