Calendar Operations Overview

The Calendar Operations module lets you define reusable actions that the calendar performs automatically. Each operation is bound to a single PLC/CODESYS variable and carries two values: one that is written when a calendar item starts, and one that is written when it ends.

Operations are created and managed centrally in this view, then assigned to calendar items. The same operation can be reused across many items, so you define the action once and apply it wherever it is needed.

How an Operation Works

When a calendar item becomes active, its assigned operations write their start value to the linked variable.
When the calendar item ends, the operations write their end value to the same variable.
Each execution is recorded in the operation log, so you can trace what was written, when, and whether it succeeded.

Operation Fields

Name — a clear label used to identify the operation when assigning it to a calendar item. Required.
Variable — the PLC/CODESYS variable the operation acts on. Select it with the variable picker so its data type is detected automatically. Required.
Start operation — the value written to the variable when the calendar item starts. Shown only after a variable is selected. Required.
End operation — the value written to the variable when the calendar item ends. Shown only after a variable is selected. Required.

Supported Variable Types

An operation can only target a variable whose data type is supported. If you select a variable of an unsupported type, the form reports a type-not-supported error and the operation cannot be saved. Supported types are:

Boolean:BOOL
Signed integers: SINT,`` INT, DINT, LINT
Unsigned integers:USINT, UINT, UDINT,ULINT
Bit strings: BYTE,WORD,DWORD,LWORD
Floating point: REAL,LREAL
Generic: NUMBER,STRING

Note: the data type is bound to the variable you pick. If you edit the variable field manually instead of using the picker, the detected type is cleared and you must re-select the variable so its type can be validated again.

Rules & Validation

Unique name — every operation must have a name, and the name cannot be duplicated. Two operations may not share the same name.
No duplicate operations — the same combination of variable + start value + end value may not be created twice. If an identical operation already exists, a new one cannot be added.
Supported variable required — the selected variable must exist and be of a supported data type.
Start and end values required — once a variable is selected, both the start value and the end value must be provided; neither may be left empty.

Managing Operations

Use New to create an operation, then assign it to calendar items where needed.
Use the edit and delete actions in the list to maintain existing operations.
Use the filter at the top of the list to quickly find an operation by name, variable, or value.

Tips

Give operations descriptive names (for example "Lights ON / OFF" or "Setpoint 21°C / 18°C") so they are easy to recognize when assigning them to items.
Make sure the start and end values are compatible with the variable's data type (for example TRUE/FALSE for a BOOL).
Reuse a single operation across multiple calendar items instead of recreating the same action.

Calender Overview