The Lock Server Service (found in the Service Structure) is used for handling of locks (for example, Process Object Locking) in the system.
Process Object Locking Aspect
The Process Object Locking aspect (Figure 155) is used for configuring the Object Locking function. By default the function is disabled.
For information about the Object Locking function, refer to the System 800xA Engineering 5.1 Process Graphics based on Visual Basic (3BSE030335*) instruction. The Process Object Locking aspect consist of two tabs which are described as follows:
From System Version 5.1 onwards, the System Configuration Console is available that can be used for a simplified configuration of the Process Object Lock functionality. Refer to System 800xA 5.1 Tools (2PAA101888*) for more information.
Configuration Tab
• Select the Object Lock enabled check box to enable the Object Lock function.
• Type number of locks that can be held by one user on one node at the same time in the Max number of simultaneous locks field. -1 specifies infinite number of locks.
• Lock Timeout controls how long a lock should be held. When the timeout is reached the lock will be broken. (Same value as the Hold Timeout in the Special Configuration tab of the Service Definition aspect)
• If the Locking optional for operation radio button is selected it is possible to operate without locking the object first.
• If the Operation requires locking radio button is selected it is required to lock the object before it is possible to operate on it.
Figure 155. Lock Server Service - Process Object Locking Aspect, Configuration Tab
The time specified below as one minute is not relevant.
• Autolock is configured per user. You can view and configure the settings for each user by selecting the user from the list and then click the View Autolock button. Refer to System 800xA Engineering 5.1 Process Graphics based on Visual Basic (3BSE030335*) instruction for more information about autolock.
Connectivity Tab
It is possible to configure if the Lock Server should be used for process object locking for each connectivity in the system. The tab contains a list of the
OPCDA_Connector services’ service groups. Select a service group and click the Go to service group button. The Service Group Definition aspect of the selected service group will open, and in the Special Configuration Tab user configures if Lock Server should be used or not. Refer to System 800xA 5.1 Configuration (3BDS011222*) for more information.
Figure 156. Lock Server Service - Process Object Locking Aspect, Connectivity Tab
Some connectivities implements process object locking without using the Lock Server. Before changing any settings read the respective connectivity instruction.
Lock Type Definition Aspect
There are three pre-defined lock types in the system; Read, Write and Control.
The Control lock type is used for process object locking.
In the Lock Type Definition aspect, configure the lock types, refer to Figure 157.
Select a lock type and click Edit. In the Lock Type Configuration dialog (see Figure 158) you can configure permission to break a lock, enable/disable the lock type, set maximum numbers of simultaneouslocks (-1 is infinite). For the Control lock type the enabled and multi lock settings are the same as the settings in the Process Object Locking aspect.
The Inclusive, Available and Exclusive lists should not be modified.
Figure 157. Lock Server Service - Lock Type Definition Aspect
Service Definition Aspect
The Special Configuration tab (see Figure 159), in the Service Definition aspect of the Lock Server object, is used for defining various timeouts.
Figure 158. Lock Type Configuration Dialog Box
Change the parameters in this section only when it is found absolutely necessary after an evaluation.
In the Timeout Configuration area you can configure timeouts in the server for:
• Grace Period - A grace period takes place when the server starts. Only saved locks are allowed to be sent to the server during this period. This to make sure that no new client locks a resource before all existing clients have re-entered their saved locks. It also gives the Resource Managers time to re-register themselves.
• Scan Interval for TimeOut - For each lock the client specifies how long it wants to wait for the lock to be granted. When this time has passed, the Lock Server will remove the lock. The Scan Interval for timeout value specifies how often the Lock Server will scan for timeout locks.
• Timeout for disabling - If the server, or connection to the server, goes down the disable timeout is started. When the timeout is reached all locks that the client holds will be broken.
In the Global Property Control Lock configuration area you can configure Figure 159. Lock Server Service - Service Definition Aspect, Special Configuration Tab
The Global Properties are used for process object locking (refer to Process Object Locking Aspect on page 191)
• Retain Lock Timeout - Sets the time for how long a lock should be held after a server failure.
• Hold Timeout - Sets the time for how long a lock should be held. When the timeout is reached the lock will be broken.
• Lock Timeout - Sets the time for how long the client will wait before the lock is granted. If the timeout is reached the lock request will be cancelled.