Data Value Functions

Data Value functions are used in calculated tag expressions to retrieve, inspect, and manipulate data values, timestamps, quality information, and trigger-related context. These functions can access historical data, return collections of values, evaluate data quality, and extract specific elements from DataValue objects.

Function Reference:

Function	Name	Description	Format	Returned Value
tagat	Data Value at Time	Returns the data value at the specified timestamp. The returned value can be raw or interpolated.	`tagat(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to retrieve.	DataValue (timestamp, value, and quality code)
tagprev	Previous Data Value	Returns the data value immediately preceding the specified timestamp.	`tagprev(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagprev2	Previous or Current Data Value	Returns the data value preceding or occurring at the specified timestamp.	`tagprev2(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagnext	Next Data Value	Returns the data value immediately following the specified timestamp.	`tagnext(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagnext2	Next or Current Data Value	Returns the data value following or occurring at the specified timestamp.	`tagnext2(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagprevgood	Previous Good Data Value	Returns the first good-quality data value preceding the specified timestamp.	`tagprevgood(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagprevgood2	Previous or Current Good Data Value	Returns the first good-quality data value preceding or occurring at the specified timestamp.	`tagprevgood2(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagnextgood	Next Good Data Value	Returns the first good-quality data value following the specified timestamp.	`tagnextgood(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagnextgood2	Next or Current Good Data Value	Returns the first good-quality data value following or occurring at the specified timestamp.	`tagnextgood2(variable, dateTime)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate.	DataValue
tagprevn	Previous N Data Values	Returns the specified number of data values preceding the timestamp.	`tagprevn(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagprevn2	Previous and Current N Data Values	Returns the specified number of data values preceding and including the timestamp.	`tagprevn2(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagnextn	Next N Data Values	Returns the specified number of data values following the timestamp.	`tagnextn(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagnextn2	Next and Current N Data Values	Returns the specified number of data values following and including the timestamp.	`tagnextn2(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagprevngood	Previous N Good Data Values	Returns the specified number of good-quality data values preceding the timestamp.	`tagprevngood(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagprevngood2	Previous and Current N Good Data Values	Returns the specified number of good-quality data values preceding and including the timestamp.	`tagprevngood2(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagnextngood	Next N Good Data Values	Returns the specified number of good-quality data values following the timestamp.	`tagnextngood(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
tagnextngood2	Next and Current N Good Data Values	Returns the specified number of good-quality data values following and including the timestamp.	`tagnextngood2(variable, dateTime, count)` variable: Specifies the internal data variable to evaluate. dateTime: Specifies the timestamp to evaluate. count: Specifies the number of values to return.	Array of DataValue objects
trgnamecur	Current Trigger Name	Returns the name of the trigger that invoked the current calculation.	`trgnamecur()`	String
trgnameprev	Previous Trigger Name	Returns the name of the trigger that invoked the previous calculation.	`trgnameprev()`	String
trgcur	Current Trigger Value	Returns the data value of the trigger that invoked the current calculation.	`trgcur()`	DataValue
calcprev	Previous Calculated Value	Returns the most recently calculated value.	`calcprev()`	DataValue
elm	Array Element	Returns the array element at the specified position.	`elm(array, arrayPosition)` array: Specifies the source array. arrayPosition: Specifies the zero-based array position.	Generic value
val	Value	Returns the value portion of a DataValue object.	`val(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Raw value
valsetgood	Value and Set Good Quality	Returns the value portion of a DataValue object and sets expression quality to Good.	`valsetgood(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Raw value
time	Timestamp	Returns the timestamp portion of a DataValue object.	`time(dataValue)` dataValue: Specifies the DataValue object to evaluate.	DateTime
qualcode	Quality Code	Returns the quality code portion of a DataValue object.	`qualcode(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Unsigned Integer
isgood	Is Data Value Good	Returns whether the specified data value has good quality.	`isgood(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Boolean
isbad	Is Data Value Bad	Returns whether the specified data value has bad quality.	`isbad(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Boolean
isunc	Is Data Value Uncertain	Returns whether the specified data value has uncertain quality.	`isunc(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Boolean
hasval	Has Value	Returns whether the specified data value contains a valid value.	`hasval(dataValue)` dataValue: Specifies the DataValue object to evaluate.	Boolean
nologval	Not Logged Value	Returns the specified value without logging it.	`nologval()`	DataValue