Methods

There are two types of method:

• Action Methods are used to perform an action, such as acknowledge an alarm or override the value of a database point. Many action methods are available as pick actions in ViewX or Virtual ViewX. Those action methods that are not available as pick actions can only be accessed 'programmatically', such as via Mimic scripting, automation, or SOAP.

  Some action methods require date or time formats to be specified. Product releases from ClearSCADA 2014 R1 inclusive do not support the use of legacy date and time syntax for specifying such formats (see Date and Time Syntax in the Geo SCADA Expert Guide to Core Configuration). If Geo SCADA Expert deems the format to be invalid, it will use the regionally localized default date and time format (such as dd/MM/yyyy hh:mm:ss:SSS). The default format is determined by the user's Locale settings (see Define the Regional Settings for a User in the Geo SCADA Expert Guide to Security).

• Calculation Methods are used to calculate a value rather than perform an action. For example, calculation methods can be used in expressions on Mimics to return a calculated value. Calculation methods do not appear as pick actions in ViewX or Virtual ViewX. You cannot call a Calculation method from Logic. If you use such a method, the following error is returned:

  Invalid DATABASE_OBJECT definition: method <method name> on <method class> is of unsupported type.

Each method has a unique name in its database table and may have arguments. The arguments (also referred to as parameters) are used to pass information to the system when the method is executed. For example, the Control method on an output point has an argument to specify the value to which the point is set.

For calculation methods, the last argument is the value that is returned by the method. When you use the Database Schema to view a calculation method, the last argument of the calculation method has a [retval] prefix.

You can use the Geo SCADA Expert Database Schema to access information about the methods that are associated with each class (see Class Information).