$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

See the General Object Configuration guide for assistance configuring the General tab.

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 regarding the client.

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.

OPC DA Trace File Options

These options relate to the OPC DA Trace File. Trace options were previously in the asiData.ini file but now have been moved to the $Server object. These settings can be changed at any time without requiring a re-start of ACM.

OPC DA Trace File Level. The below levels are cumulative. For example, Group includes both Group and Connect information and Data would include all the trace levels.
- None: No trace information is captured
- Connect: Client connects and disconnects are captured.
- Group: OPC DA group adds and removals are captured.
- Item: Add, remove, and state changes of items are captured.
- Updates: Summary information regarding data updates is captured such as number of items and when the updates occurred.
- Data: Individual value and quality updates for each item are captured.
Server OPC DA Trace File Path. The path where the OPC DA Trace file will be created. The path must exist, ACM will not create any folders for trace logging.
OPC DA Trace File Size. The maximum log file size in megabytes, 0 to 500. If 0 is entered, 10 will be used. Once the maximum log file size has been reached, a new time-stamped file will be created.

Warning: If a trace level other than “None” is selected and the Server OPC DA Trace File Path is empty, the trace information will be displayed in the ACM Logger window. A high level of trace detail can cause so much logging that the ACM Configuration may become unresponsive. Leaving the trace file path empty is not recommended.

Inter-process Logging

These options allow logging of Communication Manager internal OPC logic regarding other ACM processes, as opposed to the client.

Validate item. When an item is validated in one of the ACM processes
Add/Remove item. When an item is added or removed in one of the ACM processes.
Add/Remove group. When a group is added/removed in one of the ACM processes.
Activate/Deactivate item. When an item is activated or deactivated in one of the ACM processes.
Item read requests. When a read request occurs in one of the ACM processes.
Write item. When an item is written in one of the ACM processes.
Client connections. When a client connection occurs in one of the ACM processes.
Item data updates. When an item’s data is updated in one of the ACM processes.

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.

Note: When security is enabled and this option is not selected, it is possible to configure users and roles such that all users are locked out of the server or that no users can change the configuration.

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 not fully implemented. Historical collection only.

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.

Note

When assigned, this will override ALL device-level Alias Group assignments.

ACM User Guide