$Server Object

Overview

This object contains global settings for the instance of the ACM server.

The $Server object is located in the Object Tree root under $System. See Configuration Tab.

The $Server object also supports OPC items that provide information about the state of ACM and connected clients. See the $Server Items page for a list of the supported items.

$Server Object Configuration

Logging Tab

Log Configuration

Default = Selected. Enables/Disables logging of configuration changes.

OPC Trace Server Logging Options

These options make ACM log messages when any of these OPC actions occur.

• Validate item. When an OPC client attempts to validate an item.
• Add item. When an OPC client attempts to add an item.
• Activate/Deactivate item. When an OPC client changes the active state of an item.
• Remove item. When an OPC client removes an item.
• Sync/Async read item. When an OPC client issues a read for specific items.
• Write VQT. When an OP client writes the value, quality, and/or timestamp to an item. Does not go to field device.
• Write item. When an OPC client writes a value to an item.

Server Tab

Enable User Security

Default = Not Selected. See Security for more information.

Windows administrators have full access

Default = Selected. When security is enabled, this option allows administrator accounts full access to the ACM configuration regardless of the role assigned to the account.

Auto Shutdown

Default = Not Selected. When checked it will stop the Data Server when there are no more connected clients.

Shutdown even when auto-poll enabled

Default = Not Selected. Auto Shutdown provides a way for ACM to stop when all clients disconnect. This is useful in a redundant server setup. However, if polling is done through active alias groups, ACM will continue to run even when Auto Shutdown is enabled and all clients disconnect. Select this option along with Auto Shutdown to make ACM stop when all clients disconnect, even if ACM is polling for active alias groups.

Shutdown Timer

The shutdown timer is the amount of time in seconds the server will wait after it is manually shut down to allow connected clients a chance to disconnect. A notification will be sent to any connected clients during this time. If there are no connected clients the server will shutdown immediately.

Sync Read Timeout

This establishes the length of time (in milliseconds) the server should wait for a Sync Read to time out.

Wait For Writes

Default = Not Selected. Enables or disables write completion logic. When enabled, the server will wait for the OPC write to complete at the remote device. When disabled, the server will queue the OPC write command and return immediately to the client.  If necessary, provide a Write Timeout value which is the length of time (in milliseconds) that the server should wait for a write to complete.

Enable Persistent Item Data

Default = Not Selected. When selected, the system will store last item value in cache and use it for first value during load. A value of zero in the data age limit fields means no time limit is applied to the age of the data. 

Item Update Frequency

Default = Only Changes. This option controls data updates for non-OPC items. These are items that are shown in the ACM View screens and items that are advised through the ACM API. Items that are advised through OPC clients and HMIs will receive data and quality updates as they always have (as prescribed by the OPC specification). When this option is set to "Only Changes", the system will only send updates to clients when a value or quality change occurs. An item's "Last Updated" time will only be updated if the value or quality changes regardless of when it was last polled. When "Every Poll" is selected, the system will update an item's "Last Updated" date/time property each time the device is polled whether it's data value or quality has changed or not. 

Max Activate Item Connections

Default = 100. Max number of connections to the Item Server allowed at one time.

Database Tab

Delete Old History

Default = Selected. When Selected, provide Days of History to Keep, Time of Day to Delete and SQL Delete Timeout values if required.

Monitor Database Capacity

Default = Selected. When Selected, provide Error Message % and Warning Message % values if required.

Redundancy Tab

Redundancy Mode

Fixed for current version. 

History Collection

• Always. (Default) Always collect.

• Never. Never collect.

• Server A. Collect only when running on Server A.

• Server B. Collect only when running on Server B.

Aliasing Tab

Alias Group 

The server-wide Alias Group to use for all Alias lookups.