EAE DataType Creation

Create or modify custom data types: structures, enumerations, arrays, and subranges.

CRITICAL RULE: ALWAYS use this skill for ANY operation on DataType files.

Creating new DataTypes
Modifying existing DataTypes (adding fields, enum values, etc.)
NEVER directly edit .dt files outside of this skill

DataType Key Differences:

Uses DataType.dtd (NOT LibraryElement.dtd)
Uses Standard="1131-3" (IEC 61131-3)
Has NO GUID attribute
Located in IEC61499/DataType/ subfolder
Uses .dt extension (NOT .dtp )

Quick Start

User: Create an enumeration for machine states: Idle, Running, Error Claude: [Creates IEC61499/DataType/MachineState.dt]

Triggers

/eae-datatype
/eae-datatype --register-only
Register existing DataType (used by eae-fork orchestration)
"create enum"
"modify enum"
"create structure"
"modify structure"
"add field to structure"
"create data type"
"create array type"

When called with --register-only , this skill skips file creation and only performs dfbproj registration. This mode is used by eae-fork to complete the fork workflow after file transformation.

/eae-datatype --register-only {TypeName} {Namespace}

What --register-only does:

Registers in dfbproj - Adds ItemGroup entries for DataType visibility

What --register-only does NOT do:

Create IEC61499 files (.dt, etc.) - already done by eae-fork
Update namespaces - already done by eae-fork

Usage

Register a forked DataType

python ../eae-skill-router/scripts/register_dfbproj.py MyStatus SE.ScadapackWWW --type datatype

Verify registration

python ../eae-skill-router/scripts/register_dfbproj.py MyStatus SE.ScadapackWWW --type datatype --verify

Modification Workflow

When modifying an existing DataType:

Read the existing .dt file to understand current structure
Identify what needs to be added/changed
For structures: add/modify VarDeclaration elements
For enums: add/modify EnumeratedValue elements
For arrays: modify BaseType or Subrange
For subranges: modify limits or InitialValue

DataType Subtypes

Subtype Element Use Case

Structure <StructuredType>

Group related fields

Enumeration <EnumeratedType>

Named value sets

Array <ArrayType>

Fixed-size collections

Subrange <SubrangeType>

Constrained numeric range

Files Generated

File Purpose

{Name}.dt

Main type definition

{Name}.doc.xml

Documentation

Location: IEC61499/DataType/ (NOT IEC61499/ )

Critical Rules

Rule Value

DOCTYPE <!DOCTYPE DataType SYSTEM "../DataType.dtd">

Standard <Identification Standard="1131-3" />

GUID None (DataTypes don't have GUIDs)

Extension .dt (NOT .dtp )

Location IEC61499/DataType/ subfolder

Structure Type

Groups related fields together:

<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE DataType SYSTEM "../DataType.dtd"> <DataType Name="MotorData" Namespace="MyLibrary" Comment="Motor parameters"> <Identification Standard="1131-3" /> <VersionInfo Organization="MyOrg" Version="1.0" Author="Claude" Date="01/16/2026" Remarks="Initial" /> <CompilerInfo /> <StructuredType> <VarDeclaration Name="Speed" Type="REAL" Comment="Motor speed in RPM" /> <VarDeclaration Name="Current" Type="REAL" Comment="Current in Amps" /> <VarDeclaration Name="Running" Type="BOOL" Comment="Motor running state" /> <VarDeclaration Name="ErrorCode" Type="INT" Comment="Error code" /> </StructuredType> </DataType>

Nested Types

Enumeration Type

Named value sets:

<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE DataType SYSTEM "../DataType.dtd"> <DataType Name="MachineState" Namespace="MyLibrary" Comment="Machine states"> <Identification Standard="1131-3" /> <VersionInfo Organization="MyOrg" Version="1.0" Author="Claude" Date="01/16/2026" Remarks="Initial" /> <CompilerInfo /> <EnumeratedType> <EnumeratedValue Name="Idle" /> <EnumeratedValue Name="Starting" /> <EnumeratedValue Name="Running" /> <EnumeratedValue Name="Stopping" /> <EnumeratedValue Name="Error" /> <EnumeratedValue Name="Maintenance" /> </EnumeratedType> </DataType>

Array Type

Fixed-size collections:

<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE DataType SYSTEM "../DataType.dtd"> <DataType Name="SensorArray" Namespace="MyLibrary" Comment="Array of 10 sensor values"> <Identification Standard="1131-3" /> <VersionInfo Organization="MyOrg" Version="1.0" Author="Claude" Date="01/16/2026" Remarks="Initial" /> <CompilerInfo /> <ArrayType BaseType="REAL" Namespace=""> <Subrange LowerLimit="0" UpperLimit="9" /> </ArrayType> </DataType>

Array of Custom Types

Subrange Type

Constrained numeric values:

<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE DataType SYSTEM "../DataType.dtd"> <DataType Name="Percentage" Namespace="MyLibrary" Comment="0-100 range"> <Identification Standard="1131-3" /> <VersionInfo Organization="MyOrg" Version="1.0" Author="Claude" Date="01/16/2026" Remarks="Initial" /> <CompilerInfo /> <SubrangeType BaseType="INT" InitialValue="0"> <Subrange LowerLimit="0" UpperLimit="100" /> </SubrangeType> </DataType>

dfbproj Registration

<ItemGroup> <None Include="DataType{Name}.doc.xml"> <DependentUpon>{Name}.dt</DependentUpon> </None> </ItemGroup> <ItemGroup> <Compile Include="DataType{Name}.dt"> <IEC61499Type>DataType</IEC61499Type> </Compile> </ItemGroup>

Note: Path includes DataType
prefix.

Built-in Types Reference

Type Description Example

BOOL Boolean TRUE, FALSE

INT 16-bit signed -32768 to 32767

DINT 32-bit signed Larger integers

REAL 32-bit float 3.14159

LREAL 64-bit float High precision

STRING Text 'Hello'

STRING[n] Fixed-length STRING[15]

TIME Duration T#5s

DATE Date D#2026-01-16

Common Rules

See common-rules.md for:

dfbproj registration patterns
Documentation file template

Troubleshooting

Issue Solution

DataType not found Ensure file is in DataType/ subfolder

Wrong extension Use .dt , not .dtp

Load error Use DataType.dtd , not LibraryElement.dtd

Standard error Use Standard="1131-3" , not 61499-2

GUID error DataTypes should NOT have GUID

Validation

After creating a DataType, validate it:

python ../eae-skill-router/scripts/validate_block.py --type datatype MyType.dt

Note: DataTypes do not require ID generation (no GUIDs or hex IDs).

Templates

datatype-structure.xml
datatype-enum.xml
datatype-array.xml
datatype-subrange.xml
doc.xml

Integration with Validation Skills

Naming Validation

Use eae-naming-validator to ensure compliance with SE Application Design Guidelines:

Key Naming Rules for DataTypes (SE ADG EIO0000004686.06 Section 1.5):

DataType Convention Pattern Example

Structure strPascalCase str[A-Z][a-zA-Z0-9]*

strMotorData , strAlarmConfig

Enumeration ePascalCase e[A-Z][a-zA-Z0-9]*

eMachineState , eProductType

Array arrPascalCase arr[A-Z][a-zA-Z0-9]*

arrSensorValues , arrMotorData

Subrange (context-dependent) PascalCase Percentage , ValidRange

Validate naming before creation:

python ../eae-naming-validator/scripts/validate_names.py
--app-dir IEC61499/MyLibrary
--artifact-type DataType

Validation After Creation

Validate DataType structure

python scripts/validate_datatype.py IEC61499/DataType/strMotorData.dt

Validate with JSON output for CI/CD

python scripts/validate_datatype.py IEC61499/DataType/*.dt --json

Best Practices from EAE ADG

Naming Conventions (Hungarian Notation)

Always use Hungarian prefixes for DataTypes:

Prefix Type Example

str

Structure strMotorConfig

Enumeration eProductState

arr

Array arrSensorBuffer

Array (alternative) aValues

<DataType Name="strMotorData" Namespace="MyLibrary">

<DataType Name="MotorData" Namespace="MyLibrary">

Field Naming in Structures

Interface fields: PascalCase

Internal/private fields: camelCase

Enumeration Values

Use meaningful, action-oriented names:

Avoid generic names:

<EnumeratedValue Name="State1" /> <EnumeratedValue Name="State2" />

Documentation

Always include meaningful Comment attributes:

Type Selection

Need Use Type Rationale

Related fields Structure Groups logically connected data

Fixed set of states Enumeration Type-safe, self-documenting

Multiple values of same type Array Efficient memory, iteration

Bounded numeric values Subrange Compiler-enforced constraints

Anti-Patterns

Naming Anti-Patterns

Missing Hungarian Prefix

<DataType Name="MotorData" ...> <StructuredType>

<DataType Name="strMotorData" ...> <StructuredType>

Missing 'e' Prefix for Enum

<DataType Name="MachineState" ...> <EnumeratedType>

<DataType Name="eMachineState" ...> <EnumeratedType>

Inconsistent Field Naming

<StructuredType> <VarDeclaration Name="speed" Type="REAL" />  <VarDeclaration Name="MAX_TEMP" Type="REAL" />  <VarDeclaration Name="errorCode" Type="INT" />  </StructuredType>

<StructuredType> <VarDeclaration Name="Speed" Type="REAL" /> <VarDeclaration Name="MaxTemp" Type="REAL" /> <VarDeclaration Name="ErrorCode" Type="INT" /> </StructuredType>

Structure Anti-Patterns

Wrong DOCTYPE

<!DOCTYPE DataType SYSTEM "../LibraryElement.dtd">

<!DOCTYPE DataType SYSTEM "../DataType.dtd">

Wrong Standard

<Identification Standard="61499-2" />

<Identification Standard="1131-3" />

Including GUID

<DataType Name="strConfig" GUID="12345678-1234-...">

<DataType Name="strConfig" Namespace="MyLibrary">

Wrong Extension

BAD: strMotorData.dtp CORRECT: strMotorData.dt

Wrong Location

BAD: IEC61499/strMotorData.dt CORRECT: IEC61499/DataType/strMotorData.dt

Enumeration Anti-Patterns

Generic State Names

<EnumeratedType> <EnumeratedValue Name="State0" /> <EnumeratedValue Name="State1" /> <EnumeratedValue Name="State2" /> </EnumeratedType>

<EnumeratedType> <EnumeratedValue Name="Idle" /> <EnumeratedValue Name="Active" /> <EnumeratedValue Name="Complete" /> </EnumeratedType>

Too Many Values Without Grouping

<EnumeratedType>  </EnumeratedType>

Array Anti-Patterns

Zero-Length Arrays

<ArrayType BaseType="REAL"> <Subrange LowerLimit="0" UpperLimit="0" /> </ArrayType>

<ArrayType BaseType="REAL"> <Subrange LowerLimit="0" UpperLimit="9" /> </ArrayType>

Excessive Array Size

<ArrayType BaseType="REAL"> <Subrange LowerLimit="0" UpperLimit="9999" /> </ArrayType>

<ArrayType BaseType="REAL"> <Subrange LowerLimit="0" UpperLimit="99" /> </ArrayType>

Verification Checklist

Before deployment, verify:

Structure

DOCTYPE references DataType.dtd
Standard is 1131-3 (NOT 61499-2)
NO GUID attribute present
File extension is .dt
Located in IEC61499/DataType/ folder
Name uses str prefix (strPascalCase)
All fields have meaningful names
All fields have Comment attributes
Registered in .dfbproj with path DataType{Name}.dt

Enumeration

Name uses e prefix (ePascalCase)
All values have meaningful names
No duplicate values
Reasonable number of values (<20 typical)

Array

Name uses arr or a prefix
LowerLimit < UpperLimit
BaseType exists and is valid
Namespace specified if custom BaseType

Subrange

LowerLimit < UpperLimit
InitialValue within range
BaseType is numeric (INT, DINT, REAL, etc.)

Naming Validation

Run naming validator

python ../eae-naming-validator/scripts/validate_names.py
--app-dir IEC61499/MyLibrary
--artifact-type DataType
--json

Related Skills

Skill Relationship

eae-skill-router Parent skill, routing logic

eae-naming-validator Validate naming conventions

eae-basic-fb Uses DataTypes in VarDeclarations

eae-composite-fb Uses DataTypes in FBNetwork

eae-cat Uses DataTypes for HMI binding

eae-fork Fork DataTypes from SE libraries

eae-datatype

Safety Notice

Copy this and send it to your AI assistant to learn

Register a forked DataType

Verify registration

Validate DataType structure

Validate with JSON output for CI/CD

Run naming validator

Source Transparency

Related Skills

eae-basic-fb

eae-skill-router

eae-naming-validator