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Logic & Calculations
In some cases you need to
perform data conversions or apply logic to the current data values
coming from your server before you apply alarm conditions and
notification.
TopView contains internal
calculation engines for data manipulation and logic execution. From unit
conversions and time-based aggregates to custom-written logic functions,
"TopView Operations" and "TopView
Logic Functions" provide powerful and efficient calculation and
scripting functions.
Examples:
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Perform calculations,
logic and mathematical operations on a monitored tag’s value
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Create custom functions to
execute advanced logic and arithmetic involving one or more tag
values
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Evaluate PI Expressions using PI
Performance Equation syntax (TopView PI)
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Count the number of alarms occurring
for another tag/row/group over a time period
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Count the number of active alarms in a
tag/row/group
Basic: TopView Operations
TopView's data sources provide data values
that can be monitored for abnormal values and/or behavior.
TopView Operations
are built-in mathematical functions and logic that allow the user to
manipulate retrieved data values, or create new summary data values, through a set of built-in
mathematical functions and logic. The operation result can then be monitored in the same
manner as a raw data value.
Supported Operations include
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Bit masking
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Alarm counts (current) and totals
(over time)
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Add, subtract, multiply, divide, and
delta between current tag and a number or second tag
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Time-based average, min, max, range,
rate-of-change, standard deviation
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Square root and log of the current tag
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String search (for string/character
tag values)
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Execution of PI Expressions
Advanced:
TopView Logic Functions (Tag Expressions)
TopView Logic Functions
allow users to perform more advanced logic, operations, and
calculations involving one or more inputs (e.g. tag values).
The return value from each
Logic Function can be monitored in the same manner as raw data
values, allowing the user to apply alarm conditions and notification
to the function results.
Logic Functions support
the Visual Basic.Net language including variables, if...then...else,
arithmetic, and math functions. Each function can be written once
yet implemented multiple times for different input lists.
Example:
A tag exists for 3 different flows, one per flow meter. The user
would like to create an alarm condition for the total flow (all 3
meters). If the total flow is < 1, set the total flow value to 0.
Function: TotalFlow
Inputs: 3 tag values: Flow1, Flow2, Flow3
Function logic: (result
can be monitored by TopView)
If (flow1 + flow2 + flow3 < 1)
then
return 0
Else
return (flow1 + flow2 + flow3)
End If
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