Overview
Access types in Factory Studio define the specific methods The Device AccessType defines the defines the rules for reading and/or writing values for each data point in a project, including polling rate, read on startup, and unsolicited input acceptance. The OnDisplayOrServer Access Type controls data read and write in the project and allows it only when certain conditions are met. It is useful for projects with many communication points but not requiring constant data updates, reducing computational load, and improving performance. The OnDisplayOrServer Access Type works by checking two conditions, OnDisplay and OnServer, before permitting data read or write. OnDisplay means data can be read or written only when the display containing it is open, while OnServer means data can be read or written when the project is running as an OPC serverDevice Point. Each Point is associated with one AccessType.
Settings include among others: Polling Rate, Read on Startup, and if is enabled to do Writing.
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Creating an
Creating a NewAccessType
To create or edit and configure an AccessType, follow these steps:
Go to- Access Devices → AccessTypes.
- 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.
AccessTypes Properties
The following table describes each configuration property when creating an AccessType:
Field | Description |
|---|---|
Name | Name of this AccessType. |
Read | |
ReadPolling | Enables read polling. |
ReadPollingRate | Defines how often the address value is retrieved. |
ReadTrigger | |
Configuring AccessType as OnDisplayOrServer
On the dialog window, you need to configure the ReadEnable field to OnDisplayOrServer.
This property is enough for the Reading portion of the communication. You can also enable Writing Events by selection the WriteEventEnable checkbox.
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 is an excellent tool for 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 OnDisplayOrServer operation process is divided into two aspects:
- On Display: On Display means that your 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.
Access Type Characteristics
The OnDisplayOrServer Access Type is a great tool for projects that have a large amount of Communication Points but do not require the data to be constantly updated for all of them.
It can help computers that lack computational power to handle a huge volume of data exchange while also maintaining other modules (Scripts, Alarms, etc) at the same time.
In these situations, an OnDisplayOrServer Access Type can be beneficial to the Project's performance.
The OnDisplayOrServer Access Type operation process can be divided into two aspects:
- OnDisplay
- OnServer
| Info |
|---|
ONLY when and while ANY of these options are met, the Communication Points with this AccessType can Read/Write data. |
On Display
The OnDisplay part means that your Communication Point will only begin Reading/Writing when the Project display that contains these tags is actually open.
To illustrate, let us say we have a project with two displays: one for LineA and the other for LineB; Each display has its own specific Tags added to it (Tag.LineAProduct1..., Tag.LineBProduct1...)- 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.
Or Server
- On Server: 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
- ScriptTasks, Classes, Expression,
- or AlarmItems. In that case, you must create a new AccessType specific for them with the
- Read Enable option in Always.
Configuring an AccessType as OnDisplayOrServer
To configure an Access type as On Display Or Server, follow these steps:
- Access Devices → AccessTypes.
- Click on the plus icon.
- On the ReadPolling property, choose OnDisplayOrServer. This property is enough for the Reading portion of the communication.
- Check the WriteEvents box to Enable Writing Events.
| Info |
|---|
Only when these options are met can the DevicePoints with this AccessType read/write data. |
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