Technical Reference Manual - InduSoft

Introduction
• TimeSlice (from operating system): Causes the operating system to switch automatically between active
threads with the same priority value.
By default, the operating system executes each active thread for approximately 20ms and then switches
to the next active thread. In other words, if there are multiple active threads with the same priority value
waiting to be executed, the operating system will not execute any one active thread for more than 20ms.
• TimeSlice (from IWS): Specifies how long each IWS thread can remain continuously active.
You use this parameter in addition to the operating system's TimeSlice parameter. You configure a
TimeSlice value for each IWS thread (except the Background Task) and specify how long each thread can
remain continuously active. As long as a thread is active, the operating system can switch to that thread.
• Period (from IWS): Specifies the maximum amount of time each IWS thread (except the Background Task)
can remain inactive.
Caution: We strongly recommend that you do not modify these default values unless it is absolutely
necessary. Configuring these parameters incorrectly can cause the entire system to malfunction (for
example, CPU usage will go to 100%) and/or cause some tasks to perform poorly.
If you must change the parameter defaults, note the values before making your changes so if a
malfunction occurs you can return to the original settings.
To change the IWS TimeSlice and Period parameter default values:
1. From the IWS installation directory (for example, C:\Program Files\installation folder\Bin),
double-click \BIN to open the folder.
2. Double-click the Program Settings.INI file to open the file in Microsoft ® Notepad.
The following is a list of all parameters contained in this .ini file and their default values (in milliseconds).
[Period]
DBSpy=1000
UniDDEClient=200
UniDDE=200
Driver=20
LogWin=100
UniODBCRT=100
OPCClient=20
OPCServer=20
TCPClient=100
TCPServer=100
Viewer=50
[TimeSlice]
UniDDEClient=100
Driver=10
OPCClient=10
OPCServer=10
TCPClient=200
TCPServer=200
Viewer=200
Note: You may not see all of these parameters listed when you open your Program Settings.INI
file. However, even if a parameter is not visible in your list, IWS still uses that parameter and its
default value.
• To change the default value of a displayed parameter: In Notepad, delete the default value and type the
new value in its place.
• To change the default value of a parameter that is not displayed in your list: In Notepad, type the
parameter name exactly as shown in the following list, the equal sign, and then the new value.
3. Save the file (File > Save) and close Notepad (File > Exit).
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