Flowlink 5.1 Software Instruction Manual - Isco

Isco Flowlink 5.1 ® Software
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ensures that the both conditions must be present, or TRUE, for
the equation to be satisfied.
See also:
• Logical operators in equations on page 99
• Parentheses and order of execution on page 97
Condition Builder
Threshold
Condition
Use the Condition Builder window to define conditions for
equations.
To define a condition, choose the type of condition from the
options in the top half of the window. Then, specify the
parameters for that condition. Click OK to save the condition and
return to the Equation Builder window.
There several types of conditions:
• Threshold
• Sensor Error
• Rate of Change
• Time Table
• Range
• Rain Event
Note: To remove a previously defined condition, choose “None” as
the condition type.
Threshold conditions are TRUE when a measured reading
reaches or exceeds your defined set point.
An example of a threshold condition would read “When 2150
Area Velocity::Level is greater than or equal to 3.0 feet.”
To define the threshold condition:
1. Select a measured data type from the “When” drop-down
list.
2. Select a comparison operator.
• < (less than)
• > (greater than)
• = (greater than or equal to)
3. Enter the threshold point. The units of measure were
automatically assigned when the data type was chosen.
4. Enter a hysteresis and time duration.
Combined, the hysteresis and time duration prevent
occurrences of the condition repeatedly toggling between
TRUE and FALSE if the measured parameter hovers
near the threshold. Likewise, the duration can prevent
the condition from changing states due to a single
anomalous measurement.
A hysteresis is a tolerance for variances in the measured
data. For example, if a level condition is set for three feet
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