Properties
This item controls Apis Messages creation. Add all necessary message element items, and triggers generation of a new message when its value is being changed.
The Message Control Item item type has the following properties:
| Name | Description | ID | Flags |
|---|---|---|---|
| Description | A description of what this item does. This is free text, so you can write anything you like here. | 101 | Persisted |
| Expression | An expression used to calculate the value of this item. | 5110 | Persisted |
| ExpressionRule | Used to set the requirement of expression validation. If value is 'And', then the items used in the expression must all have been updated after the previous generation of the message. | 10105 | Persisted, Enumerated |
| MessageTrigger | This property determines how to trigger a new Apis message. | 10110 | Persisted, Enumerated |
| MessageTypeID | The ID for the message type of an Apis message. | 5300 | Persisted, Enumerated |
| NumGeneratedMessages | The number of messages generated from this control item since it started (start time). | 10120 | ReadOnly |
| ParentItem | The parent item name of this item. | 5502 | Persisted, ApisLocalItem, ExpertPage |
| Quality | Item quality - this tells you whether an item currently has a good or bad quality. It might be bad, for example, because it isn't connected or is set to the wrong type. | 3 | ReadOnly |
| Rights | Item access rights - this property may be "read", or "read write". This means that the property may only be read from, or also can be written to. For OPC items, this written value will be passed on to the external items this item comes from. | 5 | ReadOnly |
| Time | The date and time when this item was last updated. | 4 | ReadOnly |
| Type | The item canonical data type - the specific type of this item. Whether it's an integer, string, date, etc. | 1 | ReadOnly |
| Value | The current value of the item. | 2 | NormalPage |