Manage SmartSignal Models
SmartSignal models are used to predict equipment behavior under various operating conditions. A model consists of a group of related tags and historical data that have been filtered to reflect healthy equipment behavior, residual threshold settings, model settings, and testing information. Runtime data for all tags in a model are compared to the state matrix for the model to generate estimates. Through various model settings and rules, users are alerted when abnormal conditions are encountered. Models only operate when operating mode criteria have been met.
Access Model Data
You can access the data in a model associated with a SmartSignal deployment.
Procedure
Access Settings for a Model
In the SmartSignal Maintenance module, you can access the settings associated with a model.
Procedure
Model Settings
The following settings are available for a model.
Field | Descriptions |
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Active | Specifies whether or not the application should make predictions and perform data modeling using the model’s tags and configuration. Note: The deployment containing a model must be active for an active model to be processed. |
Estimation Parameters | |
Estimation Generator | The engine used to generate estimated values.
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Similarity Operator | The algorithm to be used for modeling.
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Enable VSG | Specifies whether virtual signal (estimate) generation. If NaNs and/or outliers are encountered and the number of tags containing bad data is below the Maximum % of Bad Tags threshold, the system will fill in the missing or bad data for modeled tags with virtual signal data. |
Maximum % of Bad Tags | The percentage threshold above which, the system inhibits virtual signal generation. This option is available only when Enable VSG is selected. |
Variance of Style Factor | A multiplier for the standard deviation of normal residual signals. |
Residual Smoothing | |
Smoothing Algorithm |
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Window Size | The total window (the number of data points or persistence) to use for smoothing. |
Spline Smoothing Factor | A number between 0 and 1, where the value 0 causes the greatest smoothing and a value of 1 results in no smoothing (the output values equal the input values). A typical default value is 0.1 |
State Matrix Creation | |
Downsample Algorithm | The algorithm that will be used when creating the state matrix.
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Reference Data Splits | The number of sections to which the MinMax algorithm should be applied. Used when Min Max Split is specified in the Downsample Algorithm box. |
Maximum Vectors | The maximum number of vectors to include in the state matrix. This option works with models that have auto adaptation. If the maximum vectors are larger than the target vectors, it will increase the size of the state matrix. For example, if the target vectors is set to 25 and the maximum vectors is set to 50, the first 25 times auto adaptation occurs, the state matrix will become larger, then it will stop increasing at 50. If the maximum vectors is smaller than the target vectors, this field will have no effect. |
Target Vectors | The number of vectors that will be targeted when the state matrix is created. Used when Vector Ordering is specified in the Downsample Algorithm box. |
Redundancy Check Time | Specifies when redundancy checks are to be executed (e.g., during runtime or setup of the model). They will be executed when the H-Matrix created or modified, when the Local D-Matrix is created, or both. Since the H-Matrix is relatively large, a redundancy check will take comparatively longer to run. The goal is to keep redundancies out of the estimate generation algorithm.
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Dynamic State Matrix Vectors | |
Number of Vectors |
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Similarity Percentile | Threshold used to determine whether or not vectors are different enough from each other to both be considered for the VBM state matrix. |
Minimum | Minimum number of vectors in the VBM state matrix. Only applicable when Number of Vectors is Variable. |
Maximum | Maximum number of vectors in the VBM state matrix. Only applicable when Number of Vectors is Variable. |
Auto-associative vs. Inferential Modeling Methods
At each sample, the system generates a residual vector–one element for each tag. A residual is the difference between an estimated value and a real-time value. If the system or process is behaving normally and the model is accurate, the residuals should be small with a random Gaussian distribution around 0
The system uses an Auto-Associative or Inferential modeling method when calculating residuals. When the model is Auto-Associative, the model uses every tag input to calculate the estimated state of every tag in the model. When the model is Inferential, the modeling component uses only a portion of the tag inputs to generate the estimated values for all the tags in the model.
In contrast to auto-associative modeling where all input tags contribute to the estimates for all outputs, inferential modeling uses a subset of the input tags to generate estimates for all outputs. An inferentially modeled (dependent) tag is not a contributor to the model’s output. This type of tag is useful when you want to insure that the inferred tags do not affect the estimates of the remaining tags in the model.
- If all of the model's tags have the "Is Independent" checkbox checked, then auto-associative modeling is used.
- If any (but not all) of the "Is Independent" checkboxes are unchecked, then inferential modeling is used.
- If all of the "Is Independent" checkboxes are unchecked, then inferential modeling is impossible (since it requires at least one independent tag), so modeling reverts to auto-associative.
About Virtual Signal Generation
SmartSignal provides you the option to generate a virtual signal so the modeling engine can generate estimates for tags that contain outlier or missing data values. The benefit of virtual signal generation is the ability to preserve good data that exists along with bad data in the same observation vector.
By default, when bad or missing tag data is encountered, the data feed replaces bad values with a NaN (Not a Number) and passes the data to the runtime engine. If the data is from a non-modeled tag, the runtime engine replaces the NaN with a Null and displays the affected data as a blank in graphs. If the data is from a modeled tag, the entire vector is ignored during modeling. Also, if the outlier filter algorithm is enabled and a vector contains a value that is considered an outlier, the entire vector is ignored during modeling.
If you enable the virtual signal generation function and the number of tags containing bad data (Outlier or NaN) is less than or equal to a threshold you set, the modeling engine generates estimates for tags that contain missing data values. To avoid creating NaN values in the residuals and other modeling engine outputs, the modeling engine sets the residual and SSCADI decision (for a tag that corresponds to a virtual estimate) to zero. The system also modifies all other modeling algorithms (those performing operations on input data) so they can handle the NaNs and outliers.
About the State Matrix
In a model, the state matrix is a matrix of vectors in which each vector represents one of the normal operating states (for healthy behavior) of the equipment or system. Historical data from all tags in the model are included in the matrix. Using the state matrix, the runtime engine can, in real-time, compare each observation of live data to the set of normal operating states represented in the state matrix. With this comparison, the runtime engine generates an estimate for each tag in the observation and then compares the actual value to the estimate value.
Modify Data in the Page for a Model
Use these steps to modify the values associated with a model.
Procedure
- Lock for editing the analytic that you want to modify.
- Select any cell to modify the value.
What To Do Next
When you have finished making changes, deploy the analytic instance.
Create or Rebuild a Model
In the SmartSignal Maintenance module, you can create or rebuild a model for a deployment.
Procedure
Activate or Deactivate a Model
You can activate or deactivate a model to specify whether the SmartSignal software should make predictions and perform data modeling using the tags and configuration associated with the model.
About This Task
Procedure
Results
Add Reference Data to a Model
In the SmartSignal Maintenance module, you can add reference data to an existing model.
About This Task
Procedure
Access Constants for a Model
In the SmartSignal Maintenance module, you can access the constants associated with a model.
Procedure
Rebuild a Model
When you make changes to a model (for example, by modifying tag data or training data charts), you may need to rebuild the model in order for your changes to take effect. Complete the following steps to rebuild a model.
Procedure
Copy Reference Data
You can copy the reference data from one model to other models in the same mode if the analytic is locked for editing.
About This Task
You can copy all reference values or just the new reference values that have been green stripped in the current locked session.
Reference data is the combination of green stripes and adaptation stripes. Adaptation stripes are maintained by the SmartSignal Runtime Engine and you cannot modify the adaption stripes. New Reference data refers to the stripes that have been added but not been deployed into the production instance. If you choose the option to copy only New reference data, observations in adaptation stripes are not copied to target models. Adaptation stripes in target models are not affected when copying from source model, for both options. If you choose the option to copy all reference data to target models, the adaptation stripes (observations) in source model are included. However, the adaption stripes in target models are not affected.
After the reference data is copied, if the reference data of target models are changed, the models become invalid for state matrix, and the reference data are set as user-selected.
Procedure
Modify Constants for a Model
In the SmartSignal Maintenance module, you can modify the constants for a model.
Procedure
Deploy a SmartSignal Analytic Instance
After you modify an analytic instance or model, you must deploy your changes for them to take effect.
Procedure
Results
- The analytic instance is deployed, and you can view details about the analytic instance in the Overview section in the SmartSignal Deployments page.
- The analytic instance and any notes you added appear in the Analytic Instance History window for the analytic instance for which you deployed changes.