RTXHDB Applications - Expressions and Functions

Real Time eXecutives, Inc. RTXHDB Applications -
Expressions and Functions

This capability is provided with all RTXHDB user applications, enabling users to achieve substantial savings in time and storage for accessing RTXHDB data.


Mathematical Operators

+ Addition
- Subtraction
* Multiplication
/ Division
^ Exponentiation
() Grouping

Display Functions

PERIOD() Displays the date and/or time for each time slot collected.
P_START() Displays the date and time of the first time slot collected.
P_END() Displays the date and time of the last time slot collected.
NAME(block_name) Displays variable name for variable block_name.
DESC(block_name) Displays description for variable block_name.
UNITS(block_name) Displays engineering units for variable block_name.

Single Result Calculation Functions

P_INTERVAL(n) The time between intervals.
P_SUM(expression) The sum value.
P_AVG(expression) The average value.
P_STD(expression) The standard deviation value.
P_MAX(expression) The maximum value over the collection period.
P_MIN(expression) The minimum value over the collection period.
P_MODE(expression,bins) The modal value.
P_MEDIAN(expression) The median value.
NI() The number of time slots (intervals) collected.
NU(expression) The number of time slots containing unavailable values.
NA(expression) The number of time slots containing available values.

Multiple Result Calculation Functions (returning a result for each time slot collected)

ALARM(expression, lo_alarm, lo_warn, hi_warn, hi_alarm)
AVG(expression, expression, expression, ...)
CLAMP(expression, lo_limit, hi_limit)
CLIP(expression, lo_limit, hi_limit)
CUM(expression)
EXP(expression)
INTERVAL(n) (For non-continuous process data)
LAG(expression, n)
LEAD(expression, n)
LOG10(expression)
LOGN(expression)
MAX(expression, expression, expression, ...)
MIN(expression, expression, expression, ...)
MOV_AVG(expression, n)
MOV_STD(expression, n)
SQRT(expression)

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