RTLE

EVALUATE(EXPRESSION)

• EXPRESSION: A string that can be evaluated to a result. This expression can reference other tags' current or previous values and can return any type (string, number, boolean, null, etc.).

• Examples:

  • EVALUATE('5 + 5') will always return 10.

  • EVALUATE('tag['5'] * 100') will multiply the value of the tag with ID 5 by 100.

How to Use EVALUATE

The Simulator can use the EVALUATE() tag address to perform simple operations. This acts as a separate tag and helps to create reliable real-time logic expressions (RTLE) to transform raw data without changing PLC programming.

Key Points

• Current Value: Use the value keyword to reference a tag's current value.

• Previous Value: Use the lastvalue keyword to reference a tag's previous value.

Evaluation Process

• TilliT Edge first evaluates data tags not connected to a simulator, ensuring they are up-to-date.

• Then, simulator tags are evaluated one by one.

• Tags in the simulator cannot reference other simulator tags because of the evaluation order.

Examples

Current Value:

tagId 5 has EVALUATE(value['10'] / 10 == 5) 
tagId 10 has EVALUATE(5 + 5)
Cannot be done because tag id 10 is evaluated after tag id 5

Using Previous Value:

We have a machine tag with ID 67 that represents the machine's state as an integer. The goal is to convert this integer tag into multiple boolean tags compatible with the EQUIPMENT_STATUS_ template*, which expects boolean values instead of integers.

1	Equipment Running
2	Equipment Faulted
3	Equipment Blocked
4	Equipment Stopped
5	Equipment Starved

Trigger Setup: Set up triggers for events, such as when the machine is running (value = 1).

• Conversion Using RTLE: Use RTLE to create new tags that convert the integer machine state into boolean tags. This is done using a ternary operator to evaluate the integer state as a boolean value.

• Extra Logic for Equipment Stopped: Add logic to treat both "machine fault" and "machine stopped" states as a "stopped" event.

• Assigning Tags: Each boolean tag is linked to a trigger for value > 0, which activates the respective event type.

This approach allows the creation of multiple boolean tags from a single integer tag, ensuring compatibility with templates and providing a clear representation of the machine's state.