Scripts Tasks (Reference)

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Creating Script Tasks

1. Navigate to Scripts → Tasks
2. Click the plus icon
3. Configure:
   • Name: Task identifier
   • Description: Purpose of the task
   • Language: VB.NET, C#, or Python
   • Code Source: New or Import from Library
4. Click OK
5. Double-click the row to open Code Editor

Configuration Properties

Additional Properties

Code Structure

<ac:structured-macro ac:name="warning"> ac:rich-text-body Important: Script Tasks contain only the method body code - no function declarations or wrappers. The platform automatically handles method creation, exception protection, and thread management. </ac:rich-text-body> </ac:structured-macro>

Correct Task Format

csharp

// Direct code - NO method declaration
double temperature = @Tag.Temperature;
if (temperature > 100)
{
    @Tag.AlarmActive = true;
    @Alarm.Notify("High Temperature");
}

Incorrect Format

csharp

// ? WRONG - Do not include method wrapper
public void ProcessTemperature()
{
    // Code here
}

Built-in Tasks

All solutions include predefined tasks:

Server Startup

• Executes: When TServer.exe starts
• Purpose: Initialize server-side components
• Runs before: All other server tasks
• Use for: Global initialization, connection setup

Server Shutdown

• Executes: When solution stops
• Purpose: Cleanup and finalization
• Use for: Closing connections, saving state

Client Startup

• Executes: When each client connects
• Runs on: TRichClient.exe, TSmartClient.exe, or Web browser
• Purpose: Initialize client-specific settings
• Use for: UI setup, local preferences

Client Shutdown

• Executes: When client closes
• Purpose: Client cleanup
• Use for: Saving user preferences, cleanup

Task Triggers

Event-Based Triggers

Tasks execute when specific events occur:

• Tag Change: When tag value changes
• Alarm State: When alarm activates/deactivates
• Display Events: User interactions
• Custom Events: Application-specific triggers

Time-Based Execution

Configure periodic execution:

• Period: Interval in milliseconds
• Options:
  • Fixed interval (e.g., every 1000ms)
  • Scheduled times (using expressions)
  • Calendar-based triggers

Execution Model

Threading

• Each task runs in its own thread
• Multiple tasks can execute simultaneously
• No blocking between tasks
• Automatic thread pool management

Exception Handling

• Platform provides automatic exception protection
• Errors logged but don't crash the application
• Task continues next execution cycle
• Access error details via BuildErrors

Domain Execution

<ac:structured-macro ac:name="info"> ac:rich-text-body Default Configuration: Client-side tasks are disabled by default in Solution Settings because web clients don't support them yet. Most solutions use only server-side tasks. </ac:rich-text-body> </ac:structured-macro>

Server Domain (Default):

• Executes on server computer (TServer.exe)
• Global scope across all clients
• Access to all server resources
• Typical use: Business logic, calculations, data processing

Client Domain (When Enabled):

• Executes on each client independently
• Local scope per client
• Access to display context
• Only for WPF clients (not web)

Runtime Namespace

Access task runtime information via @Script.Task namespace:

csharp

// Access task properties
int count = @Script.Task.MyTask.ExecutionCount;
TimeSpan cpu = @Script.Task.MyTask.LastCPUTime;
bool enabled = @Script.Task.MyTask.Enabled;

// Control task execution
@Script.Task.MyTask.Run();  // Force execution
@Script.Task.MyTask.Enabled = false;  // Disable task

Task Runtime Properties

Using External Resources

Calling Script Classes

csharp

// Direct access to Script Classes
var result = @Script.Class.Calculations.Process(100);

Using External DLLs

1. Add reference in Scripts → References
2. Add namespace via Namespace Declarations button
3. Use in task code

Accessing Solution Objects

csharp

// All namespaces available
@Tag.Temperature = 25;
@Alarm.Reset("Area1");
var data = @Dataset.Query("SELECT * FROM Production");
@Display.MainScreen.Open();

Language-Specific Features

VB.NET

vbnet

' Use Exit Function to stop execution
If temperature > 100 Then
    Exit Function
End If

C#

csharp

// Use return to stop execution
if (temperature > 100)
{
    return;
}

Python

python

# Standard Python syntax
if temperature > 100:
    return

Best Practices

• Keep tasks focused - Single responsibility per task
• Handle exceptions - Even with automatic protection, validate inputs
• Use appropriate triggers - Event-based for reactive, time-based for polling
• Monitor performance - Check ExecutionCount and LastCPUTime
• Document purpose - Use Description field
• Test thoroughly - Verify BuildStatus before deployment
• Consider threading - Tasks run independently, avoid shared state issues

Troubleshooting

Task not executing:

• Check InitialState is Enabled
• Verify trigger configuration
• Review BuildStatus for errors
• Check Domain setting matches deployment

Performance issues:

• Monitor LastCPUTime for slow tasks
• Check ExecutionCount for excessive runs
• Consider longer Period for time-based tasks
• Review threading conflicts

Compilation errors:

• Double-click BuildStatus red X
• Check namespace declarations
• Verify referenced objects exist
• Ensure no method wrappers included

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