Noise Controller

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Get Tag List	Set Tag List	Noise Controller	Slew Rate Controller	Downtime	Events	Scheduled Events	Profile	Queue Profile	Signal Waveform

Related Links: Noise Class

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General Description

• The Noise Controller unit operation is used to simulate process noise. It can be used to add disturbance to feeders, pipe outlet capacity, and other writeable variables.
• Standalone unit - no Pipe connections.
• Dynamic simulation only.

Diagram

The diagram shows the default drawing of the Noise control unit.

Inputs and Outputs

There are no connections to this unit.

Model Theory

The random number generator used for all probability functions is from the C++ standard library (http://www.cplusplus.com/reference/random/).

The Probability Density functions used for the Noise generation are shown in the following table. In all cases the following convention is used:

[math]\displaystyle{ \mu }[/math] = Mean Value

[math]\displaystyle{ \sigma }[/math] = Standard Deviation

For all methods, the tag PlantModel.RandomSeedAtStart (set on the Plant Model - FlwSolve page) affects the repeatability of the random values generated. For the same seed value, a repeatable set of random numbers will be generated. For a different seed, a different set of random numbers will be generated. If "*" is used, then a new random set of values will be generated on every run.

Type	Probability Density Function P(t)		NOTES
Gaussian	[math]\displaystyle{ P(t) = \cfrac{1}{\sigma \sqrt{2\pi}}\cdot e^{\dfrac{-(t-\mu)^2}{2\sigma^2}} }[/math]	where [math]\displaystyle{ \sigma \gt 0 }[/math]	Normal distribution: 68.27% of the numbers generated will be between [math]\displaystyle{ \mu-\sigma }[/math] and [math]\displaystyle{ \mu+\sigma }[/math] (see Wikipedia).
Flat	[math]\displaystyle{ P(t) = 0 }[/math]	where [math]\displaystyle{ t \lt \mu - m }[/math] or [math]\displaystyle{ t \gt \mu + m }[/math]
	[math]\displaystyle{ P(t) = \dfrac{1}{2\sigma} }[/math]	where [math]\displaystyle{ \mu - m ≤ t ≤; \mu + m }[/math] and [math]\displaystyle{ m ≥; 0 }[/math] and [math]\displaystyle{ m }[/math] = maximum deviation
Poisson	[math]\displaystyle{ P(t) = \cfrac{\mu^t}{t!}\ e^{-\mu} }[/math]	where [math]\displaystyle{ e }[/math] = the base of the natural logarithm system (2.71828...) and [math]\displaystyle{ \mu \gt 0 }[/math]
Gamma	[math]\displaystyle{ P(t) = \cfrac{1}{\Gamma(\alpha)\ \beta^{\alpha}}\ t^{\alpha-1}\ e^{-t/\beta} }[/math]	where [math]\displaystyle{ \alpha ≥ 0.5 }[/math] and [math]\displaystyle{ \beta \gt 0 }[/math]	The Chi-squared distribution is a special case of the Gamma distribution with [math]\displaystyle{ \alpha = n/2 }[/math] and [math]\displaystyle{ \beta = 2 }[/math], where [math]\displaystyle{ n }[/math] = degrees of freedom
Weibull	[math]\displaystyle{ P(t) = \alpha^{-\beta}\ \beta\ t^{\beta-1}\ e^{-(t/\alpha)^\beta} }[/math]	where [math]\displaystyle{ t = \alpha (-\ln(U))^{1/\beta} }[/math] and [math]\displaystyle{ \alpha ≥ 0.04 }[/math] and [math]\displaystyle{ \beta ≥ 0.01 }[/math] [math]\displaystyle{ U }[/math] is a randomly generated number between 0 and 1
Bernoulli	[math]\displaystyle{ P(t) = p^{t}\ (1-p)^{1-t} }[/math]	where [math]\displaystyle{ 0 ≤ p ≤ 1 }[/math]
Binomial	[math]\displaystyle{ P(t) = \dbinom{n}{t} p^{t}\ (1-p)^{n-t} }[/math]	where [math]\displaystyle{ n }[/math] is a positive integer, [math]\displaystyle{ \dbinom{n}{t} = \cfrac{n!}{t!(n-t)!} }[/math] and [math]\displaystyle{ 0 \lt p ≤ 1 }[/math]
Geometric	[math]\displaystyle{ P(t) = p\ (1-p)^{t} }[/math]	where [math]\displaystyle{ 0 \lt p ≤ 1 }[/math]
Exponential	[math]\displaystyle{ P(t) = \mu\ e^{-\mu\ t} }[/math]	where [math]\displaystyle{ \mu \gt 0 }[/math]
Extreme Value	[math]\displaystyle{ P(t) = \cfrac{1}{\beta}\ z(t)\ e^{-z(t)} }[/math]	where [math]\displaystyle{ z(t) = e^{(\alpha-t)/\beta} }[/math] and [math]\displaystyle{ \beta \gt 0 }[/math]
Log Normal	[math]\displaystyle{ P(t) = \cfrac{1}{s\ t\ \sqrt{2\pi;}}\ e^{-(\ln t-m)^2/2s^2} }[/math]	where [math]\displaystyle{ 0 \lt s ≤ 50.70 }[/math]
Cauchy	[math]\displaystyle{ P(t) = \cfrac{1}{\pi;\ \beta\ \left [1+\left (\cfrac{t-\alpha}{\beta} \right )^2 \right ]} }[/math]	where [math]\displaystyle{ \beta \gt 0 }[/math]
Fisher F	[math]\displaystyle{ P(t) = \cfrac{\Gamma; \left (\cfrac{m+n}{2} \right )}{\Gamma;\left (\cfrac{m}{2}\right )\ \Gamma;\left (\cfrac{n}{2}\right )}\ \frac{\left (\cfrac{m\ t}{n} \right )^{(m/2)}}{t\ \left (1+\cfrac{m\ t}{n} \right )^{(m+n)/2}} }[/math]	where [math]\displaystyle{ 1 ≤ m ≤ 100 }[/math] and [math]\displaystyle{ n ≥ 1 }[/math]
Student t	[math]\displaystyle{ P(t) = \cfrac{1}{\sqrt{n\ \pi;}}\ \cfrac{\Gamma;\left (\cfrac{n+1}{2} \right )}{\Gamma;\left (\cfrac{n}{2} \right )}\ \left (1+\cfrac{t^2}{n} \right )^{-(n+1)/2} }[/math]	where [math]\displaystyle{ n ≥ 0.25 }[/math]

References

1. Press W.H, Teukolsky S.A, Vetterling W.T, Flannery B.P Numerical Recipes in C (2nd Edition) Cambridge University Press 1992.
2. Sanders D.H Statistics A Fresh Approach McGraw-Hill 1990.
3. http://www.cplusplus.com/reference/random/ and related links describing each distribution.

Data Sections

The default sections and variable names are described in detail in the following tables. The default Noise Controller access window consists of 2 sections. This number may increase or decrease, based on user configuration.

Summary of Data Sections

1. NoiseCon tab - Contains a summary of all of the individual Noise Controls contained in the unit.
2. NC Tabs tab - This page contains all of the information for each individual Noise Controls, starting at 1 for the first Noise Controls.
3. Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.

NoiseCon

Unit Type: NoiseCon - The first tab page in the access window will have this name.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Tag	Display	This name tag may be modified with the change tag option.
Condition	Display	OK if no errors/warnings, otherwise lists errors/warnings.
ConditionCount	Display	The current number of errors/warnings. If condition is OK, returns 0.
GeneralDescription / GenDesc	Display	This is an automatically generated description for the unit. If the user has entered text in the 'EqpDesc' field on the Info tab (see below), this will be displayed here. If this field is blank, then SysCAD will display the UnitType or SubClass.
Requirements
On	Tick Box	The Overall Noise Control unit will be enabled or disabled using this box. This means that all of the independent Noise controllers in the unit will be disabled.
The following message and field is visible when upgrading the project with existing noise controllers from SysCAD 9.2 (or earlier) to SysCAD 9.3. Change numbering to start from 1 instead of 0. NB this affects Tags.
ChangeNumbering	Button	Update Numbering to Start from 1 instead of 0. Only visible if the noise controller was added in SysCAD 9.2 or earlier version. NB: this may affect external tag references such as reports, please adjust the external references appropriately if updating the controller numbering.
Count	Input	The number of independent Noise controllers required. This may be any number from 1 upwards. The user may also change this number at any time. The unit will always add new noise controllers after existing ones. User may delete individual Noise using the 'Delete Me' button under the individual noise controller blocks.
FreqMethod	Each Step	The noise controller output value will be set every step.
	Steps Period	The frequency of setting the noise controller output value is based on steps.
	Time Period	The frequency of setting the noise controller output value is based on simulated time period.
StepsPeriod	Input	Only visible only if FreqMethod is set to Steps Period. The number of steps which must pass before the noise controller output value is set.
StepsOffSet	Input	Only visible only if FreqMethod is set to Steps Period. Number of steps delay before the first noise controller output value is set.
StepsPassed	Display	Only visible only if FreqMethod is set to Steps Period. The number of steps that have passed since the last output value set.
TimePeriod	Input	Only visible only if FreqMethod is set to Time Period. The amount of simulated time must pass before the noise controller output value is set.
TimeOffSet	Input	Only visible only if FreqMethod is set to Time Period. Simulated time delay before the first noise controller output value is set.
TimePassed	Display	Only visible only if FreqMethod is set to Time Period. The amount of simulated time that has passed since the last output value set.
SetAtStartUp	Tick Box	With this option selected, the noise controller output value will be set during Startup step.
SetTagAlways	Tick Box	Only visible only if FreqMethod is set to Steps Period or Time Period. With this option selected, the noise controller output value will be set every step.
Options
ShowCnv	Tick Box	With this option selected, SysCAD will display engineering units for the Output tag. Note that these will only be displayed after SysCAD has completed at least one step.
ShowOnePerPage	Tick Box	With this option selected, SysCAD will display each noise block per tab page. If not selected, each page displays four Noise Controllers.
Check Tags	Button	SysCAD will perform a check on the validity of the tags and functions used in the noise controllers.
Summary shows a summary table with the following values for each individual noise controller in the unit.
NC	Display	The Noise Controller number
Action	On	The random number generator is on and the controller will be setting the output tag at the specified frequency.
	Off	The random number generator is off and the controller will NOT be setting the output tag.
	Manual (User)	The random number generator is off but the controller will be setting the output tag to the User value (ManualOutput) at the specified frequency.
	Manual (Mean)	The random number generator is off but the controller will be setting the output tag to the mean value at the specified frequency.
Output	Display	The output value for the individual Noise Controller.
DevFrac	Display	The deviation fraction, when compared with mean value; for each individual Noise Controller.
OutputUnitTag	Display	The output tag for each individual Noise Controller.

NC1: Individual Noise Controller Data Fields

Noise Controller is displayed on the NCx pages.

• If "ShowOnePerPage" is NOT selected, then each page displays four Noise Controllers.
• If "ShowOnePerPage" is selected, then each page displays one Noise Controller.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
[NC number]
Action	On	The random number generator is on and the controller will be setting the output tag at the specified frequency.
	Off	The random number generator is off and the controller will NOT be setting the output tag.
	Manual (User)	The random number generator is off but the controller will be setting the output tag to the User value (ManualOutput) at the specified frequency.
	Manual (Mean)	The random number generator is off but the controller will be setting the output tag to the mean value at the specified frequency.
Name	Input	The user may give the Noise Controller a name that describes the control, such Feed_Variation.
Index	Display	Controller Index. Useful for sorting the controller in reports
Type	Gaussian	Distribution method as described in the Model Theory above. 68.27% of the numbers generated will be between (Mean - StdDev) and (Mean + StdDev).
	Flat	Distribution method as described in the Model Theory above.
	Poisson	Distribution method as described in the Model Theory above.
	Gamma	Distribution method as described in the Model Theory above.
	Weibull	Distribution method as described in the Model Theory above.
	Bernoulli	Distribution method as described in the Model Theory above.
	Binomial	Distribution method as described in the Model Theory above.
	Geometric	Distribution method as described in the Model Theory above.
	Exponential	Distribution method as described in the Model Theory above.
	ExtremeValue	Distribution method as described in the Model Theory above.
	LogNormal	Distribution method as described in the Model Theory above.
	Cauchy	Distribution method as described in the Model Theory above.
	Fisher_F	Distribution method as described in the Model Theory above.
	Student_t	Distribution method as described in the Model Theory above.
ManualOutput	Value	Only visible when Action is set to Manual (User). The output tag will be set to this value instead of a randomly generated number.
StdDevInput	Only visible if Type = Gaussian or Flat
	Value	The user specifies the Standard Deviation value.
	Fraction	The user specifies the Standard Deviation as a fraction of the Mean value.
Mean	Input	Only visible if Type = Gaussian, Flat, Poisson or Exponential. The mean value around which the random number must be generated.
StdDev	Input/Calc	Only visible if Type = Gaussian. The standard deviation around the mean value.
StdDevFrac	Input/Calc	Only visible if Type = Gaussian. The standard deviation expressed as a fraction of the mean value.
MaxDev	Input/Calc	Only visible if Type = Flat. The maximum deviation around the mean value.
MaxDevFrac	Input/Calc	Only visible if Type = Flat. The maximum deviation expressed as a fraction of the mean value.
Alpha	Input	Only visible if Type = Gamma, Weibull, ExtremeValue or Cauchy. The alpha parameter as described in the Model Theory above.
Beta	Input	Only visible if Type = Gamma, Weibull, ExtremeValue or Cauchy. The beta parameter as described in the Model Theory above.
n	Input	Only visible if Type = Binomial, Fisher_F or Student_t. The n parameter as described in the Model Theory above.
p	Input	Only visible if Type = Bernoulli, Binomial or Geometric. The probability (of success) parameter as described in the Model Theory above.
m	Input	Only visible if Type = LogNormal or Fisher_F. The m parameter as described in the Model Theory above.
s	Input	Only visible if Type = LogNormal. The s parameter as described in the Model Theory above.
OutputTag	Input	This is the Tag that will be set. This tag must be copied from the relevant unit. For example: Plant_Feed.QmReqd (t/h), Feed_Water.T_Reqd (C) or P_001.Qm_Capacity (kg/h). Note 1: Only input data fields (i.e. white) can be used here. Note 2: This field is optional.
OutputUnitTag	Display	The Unit Operation Tag. For example: If the Output Tag is Plant_Feed.QmReqd (t/h), then the OutputUnitTag is Plant_Feed.
OutputValue / Output	Calc	The output value.
Dev	Calc	The deviation value: (output - mean).
DevFrac	Calc	The deviation fraction: (output - mean)/mean.
Delete	Button	This allows the user to Delete the current individual noise controller. Please note that there is no 'Undo'!
MoveUp	Button	This allows the user to increase the Priority of the current individual noise controller. For example, if the current noise controller is number 3, the user can change it to 2 or 1 by clicking on this button once or twice.
MoveDown	Button	This allows the user to decrease the Priority of the current individual noise controller. For example, if there are 3 noise controller in the unit and the current noise controller is number 1, the user can change it to 2 or 3 by clicking on this button once or twice.

Adding this Model to a Project

Add to Configuration File

Sort either by DLL or Group:

	DLL:	ControlDyn.dll	→	Units/Links	→	Control 2: Noise
or	Group:	General	→	Units/Links	→	Control 2: Noise

See Model Selection for more information on adding models to the configuration file.

Insert into Project Flowsheet

Insert Unit

→

Control 2

→

Noise

See Insert Unit for general information on inserting units.

Example Project

• Dynamic Plant Example Project
• Tailings Dam Example Project