Overview
The Device AccessType defines the Each Point is associated with an AccessType, which defines the rules for reading and/or writing values for that Point, such as the polling rate, whether a read is performed on startup, and whether you write values to that Point. The AccessType allows users to configure how clients can access data points in the system.
Access Types define the specific methods for reading and writing values for each Device Point in a solution, including settings such as polling rate, read on startup, and unsolicited input acceptance.
Device Point. Each Point is associated with one AccessType.
Settings include among others: Polling Rate, Read on Startup, and if is enabled to do Writing.In addition, the platform provides On Display Or Server Access Type configurations that enable your solution to control the data read and write permissions. These configurations are useful for solutions with many Device Points but do not require constant data updates, reducing computational load and improving performance.
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Creating an
Access TypeAccessType
To create and configure an Access TypeAccessType, follow these steps:
- Access Devices → Access TypesAccessTypes.
- Click on the plus icon.
- Fill all the property fields with your desired configuration (see the table below for more details about each option).
- Click Ok.
Access Types properties
AccessTypes Properties
The following table describes each configuration property when creating an Access TypeAccessType:
Field | Description |
---|---|
Name | Name of this |
AccessType. | |
Read |
ReadPolling | Enables read polling. |
ReadPollingRate | Defines how often the address value is retrieved. |
ReadTrigger | Enter an object property that tells the system when to read the value. |
OnStartup | When selected, the system reads the value on startup. |
Write |
WriteEvents | Enables the writing of values to the PLC. |
WriteEvent | Defines when is the value written. |
WriteTrigger | Enter an object property that tells the system when to write the value. |
Settings |
AcceptUnsolicited | If enabled, the system accepts values from the PLC, even if the polling time has not yet elapsed. |
UseStaticBlocks | Enables the use of the block command field. |
BlockCommand | A definition for each block that will be created. Check the driver documentation to see if the specific driver uses this field and the valid values. |
Description | Description of the access type. |
OnDisplayOrServer setting
The OnDisplayOrServer AccessType
On Display Or Server type
The On Display Or Server Access Type is an excellent tool for projects solutions with many communication points but only requires data updates for some of them. It can help computers without the computational power to handle massive data exchange while maintaining other modules active. The On Display Or Server OnDisplayOrServer operation process is divided into two aspects:
- On Display: On Display means that your Device Point DevicePoint will only begin reading or writing when the solution's display containing these tags is open.
- Let us imagine a project with two displays, one for Line A and another for Line B. Each display has its specific Tags added to it. When the Project is running, there is no need to send or receive data for all tags in the PLC. The solution only needs to send or receive data for the opened displays of the visualizer. So, when the Line A display is open, only Line A tags will communicate. The same goes for LineB.
- On Server: OrServer On Server or OPCServer means that if your solution runs as an OPC Server, the Access Type will behave as if its Read Enable property is set to Always.
- Suppose you have the tags on the server side as Script TasksScriptTasks, Classes, Expression, or Alarm ItemsAlarmItems. In that case, you must create a new Access Type AccessType specific for them with the Read Enable option in in Always.
Configuring an
Access Type as On Display or ServerAccessType as OnDisplayOrServer
To configure an Access type as On Display Or Server, follow these steps:
- Access Devices → Access TypesAccessTypes.
- Click on the plus icon.
- On the Read PollingReadPolling property, choose On Display Or ServerOnDisplayOrServer. This property is enough for the Reading portion of the communication.
- Check the Write EventsWriteEvents box to Enable Writing Events.
Info |
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Only when these options are met can the Device Points DevicePoints with this Access Type AccessType read/write data. |
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