Promotic

Object ExtWriteAction

Description:
An extension of the PmVar variable of the PmaData object for testing and modification of written value.
Properties and methods:
ExtIdData extension identifier
MaxSubstQualityReplacement quality
MaxSubstQualityEnabledWrite replacement quality
MaxSubstValueReplacement value
MaxSubstValueEnabledWrite replacement value
MaxTestEnabledTesting the maximum allowed value of the variable
MaxValueMaximum allowed value of the variable
MinSubstQualityReplacement quality
MinSubstQualityEnabledWrite replacement quality
MinSubstValueReplacement value
MinSubstValueEnabledWrite replacement value
MinTestEnabledTesting the minimum allowed value of the variable
MinValueMinimum allowed value of the variable
QualitySubstValueReplacement value if the quality is bad
QualityTestEnabledTesting the value quality
VarReturns the PmVar object
Configuration windows:
ExtWriteActionData extension configuration
Note:
Caution: This extension is used for extended configuration of the PmVar object functionality related to writing a new value. This does not cause connection of the PmVar object with other system components (e.g. alarms, events, trends, communications etc.). Therefore there can be only one such extension in the PmVar object (the extended functionality is either present or not present).
 
The order of processing the written value:
- calling the onItemBeforeWrite event
- rounding and transforming the written value to desired data type
- testing the written value for quality
- testing the written value for minimum
- testing the written value for maximum
- calling the onItemAfterWrite event
 
If calling the onItemBeforeWrite event is enabled, then the event is triggered for this variable always closely before writing or before the change of the variable value. Unconsidered enabling for all variables can cause unnecessary utilization of the processor. For example if the object includes 1000 variables and each one has calling enabled then by writing new values into all variables of the object can cause calling the onItemBeforeWrite event 1000 times (each time with another pEvent.Item parameter value). It is also better (if it is required to react to writing or the change of the variable) to enable the onItemAfterWrite event instead of onItemBeforeWrite. Enabling onItemBeforeWrite is useful only if, for example, you need to test the written value and in a necessity to change it (to filter it). The onItemBeforeWrite property in the onItemBeforeWrite event is defined for read and write and therefore it is possible in the event to enforce another value than the one that is really written.
If calling the onItemAfterWrite event is enabled, then the event is triggered for this variable always after writing or the change of the variable. For enabling this event similar remarks are valid for the onItemBeforeWrite event. Enabling the onItemAfterWrite is useful for variables that change their value not too ofter and then is it suitable to enable calling 'after the change'.
Caution: The onItemBeforeWrite event and the onItemAfterWrite event is not triggered if it isn't written into the variable directly, i.e. if the variable is bind to another value.

Format of saving the data extension in the form of string:
The content of complete of data extension (all configurators) can be saved in the form of single string. See Format of saving the data extension in the form of string.
Id={WriteAction; BeforeWrite; AfterWrite; QualityTestEnabled; QualitySubstValue; MinTestEnabled; MinValue; MinSubstValueEnabled; MinSubstValue; MinSubstQualityEnabled; MinSubstQuality; MaxTestEnabled; MaxValue; MaxSubstValueEnabled; MaxSubstValue; MaxSubstQualityEnabled; MaxSubstQuality}
- Id: see the "Data extension identifier" configurator
- BeforeWrite: see the "Event "onItemBeforeWrite"" configurator
- AfterWrite: see the "Event "onItemAfterWrite"" configurator
- QualityTestEnabled: see the "Test of value quality" configurator
- QualitySubstValue: see the "Use replacement value" configurator
- MinTestEnabled: see the "Test minimal value" configurator
- MinValue: see the "Minimum" configurator
- MinSubstValueEnabled: see the "Use replacement value" configurator
- MinSubstValue: see the "Use replacement value" configurator
- MinSubstQualityEnabled: see the "Use replacement quality" configurator
- MinSubstQuality: see the "Use replacement quality" configurator
- MaxTestEnabled: see the "Test maximum value" configurator
- MaxValue: see the "Maximum" configurator
- MaxSubstValueEnabled: see the "Use replacement value" configurator
- MaxSubstValue: see the "Use replacement value" configurator
- MaxSubstQualityEnabled: see the "Use replacement quality" configurator
- MaxSubstQuality: see the "Use replacement quality" configurator

History:
Pm9.00.13: Added testing of the written value for quality, minimum and maximum.
Pm8.03.00: Created
PROMOTIC 9.0.18 SCADA system documentation - MICROSYS, spol. s r.o.

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