Alias Group

Overview

Custom item names can be introduced into ACM by adding Alias items in an Alias Group object. This can be done at a Server level in the Aliasing tab of the $Server object, or at a device level in the Options tab of a device object.

An Alias Group object defines the alias items and the protocol item names that they are linked to. For example, to create an alias for register 5176 which is Mass for the Modbus Omni Protocol, you would enter the Alias Name as ‘ModbusOmniDevice.Mass’, and the corresponding item name would be entered as ‘ModbusOmniDevice.5176’.

At a device level this alias group provides aliasing for items in that device only. Alias item names in this group MUST NOT include the device name, but only item name. With this option, the Alias group can be shared between devices of the same protocol if the tags are the same.

For the same example at the device level, an alias name would be entered as ‘Mass’, and the corresponding item name would be entered as ‘5176’. An OPC Client that wanted the Mass value from the device named ModbusOmniDevice would use an OPC item named ‘ModbusOmniDevice.Mass’.

Item modifiers and item scaling can be used in alias groups, but the modifier will be appended to the item name and NOT the alias name.

For example if the raw value returned for Mass is 2500 and the scaled value should be .25, the alias name might be entered as ‘Scaled Mass’ and the item name would be entered as ‘5176{SG:.001,0}’.

For more information on item scaling, please see Item Scaling section.

Configuration

General Tab

See General Object Configuration page.

Alias Records

Activate Tags

The Activate Tags checkbox allows group tags to activate internally without waiting for a client to connect and activate them. Selecting this option will cause ACM to poll all the items in the Alias group without being in an OPC Client.

Edit Records

Click the Edit Records button to open the Alias Record Collection dialog box to add the alias names and item names.

Click Add to enter the appropriate number of New Record items.

Click Remove to delete any unwanted New Record items.

Click Tabular Display to view all New Record items at once.

Alias Name

The name by which the itemwill be referenced.  Max Length: 255 characters.

Item Name

The item name of the point in the device.  Modifiers and scaling can appended to the Item Name.  Max Length: 255 characters.

Record Id

Used to describe this entry.  Max Length: 50 characters.