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Alarms
Low-Low, Low, High and High-High Alarms limits may be set.
Deadband
This is the Alarm Deadband. For example, if the High Alarm is 7.00, and the deadband
is 0.10, the alarm will activate at 7.01 and deactivate at 6.90.
Alarm & Datalog
Suppression
If any of the relays or digital inputs are selected, any alarms related to this input
will be suppressed if the selected relay or digital input is active. At the same time,
all datalogs and graphs containing the input will show no data for the duration of
the activation.
Input
Select the physical input whose raw value will be used as this virtual input.
Smoothing Factor
Increase the smoothing factor percentage to dampen the response to changes. For
example, with a 10% smoothing factor, the next reading shown will consist of an aver-
age of 10% of the previous value and 90% of the current value.
Name
The name used to identify the input may be changed.
Type
Select the type of input; either Calculation, Redundant, Raw Value, Disturbance,
or Not Used.
5.2.23
Virtual Input - Disturbance
A Disturbance type Virtual Input is not a physical input. The value of the virtual input is calculated from a real
sensor input plus an equation that defines the real sensor’s impact on a control output that is using a different real
sensor. A common example is controlling pH based upon a pH input signal, but modifying control based upon the
flow rate, with a Disturbance Type Virtual Input defining the impact of the flow rate on the control output.
Based on the disturbance input channel selection, minimum and maximum disturbance input readings, and de-
fined multiplier values at the min and max disturbance readings, this Virtual Input generates a value that is used to
multiply to a primary control value. Disturbance input channel values that result in a multiplier output of 1.0 have
no impact on the final control output. The output value is restricted between low and high limits to allow more
complete control over the impact of disturbance inputs. The value of the multiplier at min disturbance can be either
higher or lower than its value at max disturbance, depending upon what effect is desired on the control setpoint.
Min Disturbance
Max Disturbance
Disturbance Input Value
Multiplier Value sent to
Disturbance Algorithm
Value at
Min Disturbance
Value at
Max Disturbance
Virtual Input Details
The details for a virtual input include the current multiplier value calculated, the current values of the inputs used
in the calculation, alarms, the status, and the input type.
Settings
Touch the Edit icon to view or change the settings related to the virtual input.
