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"

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Register-Only Mode (for eae-fork Orchestration)

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:

1. 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:

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

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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

<VarDeclaration Name="Status" Type="MachineStatus" Namespace="MyLibrary" />

---

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

<ArrayType BaseType="MotorData" Namespace="MyLibrary">
  <Subrange LowerLimit="0" UpperLimit="3" />
</ArrayType>

---

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

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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

1. Naming Conventions (Hungarian Notation)

Always use Hungarian prefixes for DataTypes:

Prefix	Type	Example
str	Structure	strMotorConfig
e	Enumeration	eProductState
arr	Array	arrSensorBuffer
a	Array (alternative)	aValues

<!-- CORRECT: Hungarian notation -->
<DataType Name="strMotorData" Namespace="MyLibrary">

<!-- INCORRECT: No prefix -->
<DataType Name="MotorData" Namespace="MyLibrary">

2. Field Naming in Structures

Interface fields: PascalCase

<VarDeclaration Name="Speed" Type="REAL" />
<VarDeclaration Name="MaxTemperature" Type="REAL" />

Internal/private fields: camelCase

<VarDeclaration Name="lastValue" Type="REAL" />
<VarDeclaration Name="errorCount" Type="INT" />

3. Enumeration Values

Use meaningful, action-oriented names:

<EnumeratedType>
  <EnumeratedValue Name="Idle" />
  <EnumeratedValue Name="Starting" />
  <EnumeratedValue Name="Running" />
  <EnumeratedValue Name="Stopping" />
  <EnumeratedValue Name="Faulted" />
</EnumeratedType>

Avoid generic names:

<!-- BAD -->
<EnumeratedValue Name="State1" />
<EnumeratedValue Name="State2" />

4. Documentation

Always include meaningful Comment attributes:

<DataType Name="strMotorData" Namespace="MyLibrary"
          Comment="Motor operating parameters and status">
  <VarDeclaration Name="Speed" Type="REAL" Comment="Motor speed in RPM" />
  <VarDeclaration Name="Current" Type="REAL" Comment="Motor current in Amps" />
</DataType>

5. 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

1. Naming Anti-Patterns

Missing Hungarian Prefix

<!-- BAD: No 'str' prefix for structure -->
<DataType Name="MotorData" ...>
  <StructuredType>

<!-- CORRECT: Hungarian prefix -->
<DataType Name="strMotorData" ...>
  <StructuredType>

Missing 'e' Prefix for Enum

<!-- BAD: No 'e' prefix for enumeration -->
<DataType Name="MachineState" ...>
  <EnumeratedType>

<!-- CORRECT: Hungarian prefix -->
<DataType Name="eMachineState" ...>
  <EnumeratedType>

Inconsistent Field Naming

<!-- BAD: Mixed conventions -->
<StructuredType>
  <VarDeclaration Name="speed" Type="REAL" />        <!-- lowercase -->
  <VarDeclaration Name="MAX_TEMP" Type="REAL" />     <!-- SCREAMING_CASE -->
  <VarDeclaration Name="errorCode" Type="INT" />     <!-- camelCase -->
</StructuredType>

<!-- CORRECT: Consistent PascalCase for interface fields -->
<StructuredType>
  <VarDeclaration Name="Speed" Type="REAL" />
  <VarDeclaration Name="MaxTemp" Type="REAL" />
  <VarDeclaration Name="ErrorCode" Type="INT" />
</StructuredType>

2. Structure Anti-Patterns

Wrong DOCTYPE

<!-- BAD: Using LibraryElement.dtd -->
<!DOCTYPE DataType SYSTEM "../LibraryElement.dtd">

<!-- CORRECT: DataType.dtd -->
<!DOCTYPE DataType SYSTEM "../DataType.dtd">

Wrong Standard

<!-- BAD: Using 61499-2 -->
<Identification Standard="61499-2" />

<!-- CORRECT: IEC 61131-3 -->
<Identification Standard="1131-3" />

Including GUID

<!-- BAD: DataTypes should NOT have GUIDs -->
<DataType Name="strConfig" GUID="12345678-1234-...">

<!-- CORRECT: No GUID attribute -->
<DataType Name="strConfig" Namespace="MyLibrary">

Wrong Extension

BAD:  strMotorData.dtp
CORRECT: strMotorData.dt

Wrong Location

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

3. Enumeration Anti-Patterns

Generic State Names

<!-- BAD: Non-descriptive -->
<EnumeratedType>
  <EnumeratedValue Name="State0" />
  <EnumeratedValue Name="State1" />
  <EnumeratedValue Name="State2" />
</EnumeratedType>

<!-- CORRECT: Meaningful names -->
<EnumeratedType>
  <EnumeratedValue Name="Idle" />
  <EnumeratedValue Name="Active" />
  <EnumeratedValue Name="Complete" />
</EnumeratedType>

Too Many Values Without Grouping

<!-- BAD: 20+ values without structure -->
<EnumeratedType>
  <!-- Consider using multiple enums or a different approach -->
</EnumeratedType>

<!-- CORRECT: Group related states or use bit flags -->

4. Array Anti-Patterns

Zero-Length Arrays

<!-- BAD: Empty array -->
<ArrayType BaseType="REAL">
  <Subrange LowerLimit="0" UpperLimit="0" />
</ArrayType>

<!-- CORRECT: At least 1 element -->
<ArrayType BaseType="REAL">
  <Subrange LowerLimit="0" UpperLimit="9" />
</ArrayType>

Excessive Array Size

<!-- BAD: Very large array (memory concerns) -->
<ArrayType BaseType="REAL">
  <Subrange LowerLimit="0" UpperLimit="9999" />
</ArrayType>

<!-- CORRECT: Reasonable size, consider chunking if needed -->
<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

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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