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| − | <h1 class="main-heading">Expression, Event and Alarms</h1> | + | <h1 class="main-heading">Expression, Event, Alarm</h1> |
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| − | === Rule, Alert === <!--T:20-->
| + | The modern building is alive with activities. Not just human activities, but activities of the systems that exists within, and those that interacts with it from the outside. These activities are mostly unseen and untapped – we typically only make use of a fraction of the data being generated. |
| − | In an operating environment such as a smart building, it is important that organizations are able to keep track and be aware of what is going on in and around their assets. The way to do that is through monitoring and alerting.
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| − | <!--T:21-->
| + | Building data can be ingested by Senfi to facilitate automation and improve building operations. To do so, Senfi provides an event-driven autonomous workflow engine. Similar to other event-driven architectures, users may define events in Senfi and specify actions to be carried out when an event occurs. Senfi provides a flexible way to define the conditions for triggering events in the form of an expression. Events may also optionally raise alarms, if it is intended to be handled by a human operator. |
| − | Sensors produce measurements which contain data in the form of metrics and tags. Senfi provides multiple ways for users to monitor metric and tag values for conditions which require attention - such as abnormally high values, or when a combination of values indicates something is down - and to take action when it happens.
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| − | ==== Rule ==== <!--T:22--> | + | === Implementing autonomous workflow in Senfi === |
| − | User can make use of Senfi's flexible rule engine to be alerted of abnormality in the system they are monitoring.
| + | Users may implement autonomous workflows by configuring the following in the CMS: |
| | + | * [[V2/Concepts/Expression|Expression Editor]] |
| | + | * [[V2/Concepts/Event|Event]] |
| | + | * [[V2/Concepts/Alarm|Alarm]] |
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| − | <!--T:23-->
| + | [[File:Concepts_Automation_Engine_Overview.png|800px|center|link=]] |
| − | A '''rule''' in Senfi comprises of:
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| − | * Inputs
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| − | * Conditions
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| − | * Output
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| − | * Actions
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| − | * Rule execution options
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| | | | |
| − | ==== Example ==== <!--T:24-->
| + | <!-- |
| − | Using our Smart Weighing Scale measurement from earlier, we can form one simple rule as follows:
| + | First, User has to design an Expression specifying conditions that Senfi has to check for, in order to detect the event or situation that the User wishes to be notified of. So when data is being pumped into Senfi, relevant data will go through the Expression for autonomous checking, and if the set of conditions evaluates to true, an Event can be triggered. |
| − | * Input: <tt><tvar|battery_level>iot_weighingscale_v1.battery_level</></tt>
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| − | * Condition: < 20
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| − | * Action: ''Email reminder to replace battery''
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| − | * Rule execution option: Immediately (means evaluate this rule whenever there is any incoming measurement)
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| − | <translate>
| + | User can define the actions to be taken when the Event is triggered, such as sending notifications to relevant personnel, sending commands to systems for actions to be taken, or sending out webhooks to external systems such as work order systems. |
| − | <!--T:1-->
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| − | As introduced in [[Concepts#Rule,_Alert|general concepts]], a '''rule''' is a tool that you can use to monitor your assets and be notified of abnormal situations or events. You can configure a rule to send email or notify your operators in the dashboard. Examples of use cases include: a fire is detected in a building, a lift has broken down, or when a machine is overdue for maintenance. Rule is the tool you can use to configure these notifications.
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| − | <!--T:2-->
| + | In the case where an Event is a notable situation and requires attention, User can set the Event to trigger an Alarm in the Digital Twin. In this way, all Users monitoring the Digital Twin will be alerted. |
| − | A rule in Senfi comprises of:
| + | --> |
| − | * Inputs - Metric & Tag values
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| − | * Conditions
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| − | * Result - True or False, a Boolean value
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| − | * Actions - Do something when Result changes. e.g. send notification email
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| − | * Rule execution options - Configures when a Rule is evaluated
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| − | <!--T:3-->
| + | ==== What's Next ==== |
| − | '''Inputs''' are evaluated by '''Conditions''' to generate a single boolean '''Result'''.
| + | ----- |
| − | When value of '''Result''' changes, '''Actions''', such as email and dashboard alerts, are executed.
| + | * Learn about [[V2/Concepts/Expression|Expression]] |
| − | '''Rule execution options''' allows you to configure how the Rule is executed. e.g: how often the '''Rule''' is evaluated, when to execute '''Actions''' etc.
| + | * Learn about [[V2/Concepts/Event|Event]] |
| − | | + | * Learn about [[V2/Concepts/Alarm|Alarm]] |
| − | <!--T:4-->
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| − | Inputs --> Conditions --> Result
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| − | | |
| − | <!--T:5-->
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| − | Result Changed --> Actions
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| − | | |
| − | == Example == <!--T:6--> | |
| − | * Input: <tt>iot_weighingscale_v1.battery_level</tt>
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| − | * Condition: < 20
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| − | * Action: ''Email reminder to replace battery''
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| − | * Rule execution option: Immediately (means evaluate this rule whenever there is any incoming measurement)
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| − | | |
| − | == Inputs, Conditions and Result == <!--T:7--> | |
| − | | |
| − | <!--T:8-->
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| − | Before adding a Rule, you should already have an event or situation that you wish to be notified about. The event or situation should be one that can be detected by monitoring data received by Senfi.
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| − | | |
| − | <!--T:9-->
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| − | Select, as '''Inputs''', the '''Metrics''' and '''Measurements''' from which the event or situation can be detected from. Then, [[#Constructing_Condition|construct the set of '''Conditions''']] that will evaluate to true when event or situation occurs. The result of said '''Conditions''' is the '''Result''' of the Rule.
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| − | | |
| − | == Actions == <!--T:10-->
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| − | Whenever '''Result''' changes (from true to false and vice versa), '''Actions''' may be executed. '''Actions''' includes sending an email, request to a webhook or triggering an alert in the dashboard.
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| − | | |
| − | === Content of Actions === <!--T:11-->
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| − | Depending on the '''Action''', different content options are available. Some examples is the title & body of an email, and body content for webhook request. You will be able to describe the event or situation that has happened to the recipient of the notification in the content of an '''Action'''
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| − | | |
| − | <!--T:12-->
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| − | To further aid you in describing the event, you can embed the value or tag of an '''Input''' metric in the content of an '''Action'''. You can also embed the Rule's [[#Name_and_Description|Name, Description]] and [[#Severity|Severity]] in the content of an '''Action'''.
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| − | | |
| − | <!--T:13-->
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| − | To embed:
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| − | * metric's value, use <tt>${<measurement_code>.<metric_code>}</tt>. e.g: <tt>${iot_temperature_sensor_v1.temperature}</tt>
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| − | * metric's tag, use <tt>${<measurement_code>.<tag>}</tt>. e.g: <tt>${iot_temperature_sensor_v1.site_id}</tt>
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| − | * Rule's name, use <tt>${NAME}</tt>.
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| − | * Rule's description, use <tt>${DESCRIPTION}</tt>.
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| − | * Rule's severity, use <tt>${SEVERITY}</tt>.
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| − | | |
| − | <!--T:14-->
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| − | <div class="important">Note: embedding Rule's name, description and severity is case sensitive. You must use all capital letters.</div>
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| − | | |
| − | <!--T:15-->
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| − | Take a look at [[#Detailed_Example | this more detailed example]].
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| − | | |
| − | == Rule execution options == <!--T:16-->
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| − | By setting '''Evaluate Type''' to '''Immediate''' or '''Polling''', you can choose to execute a Rule when new values are received for any Input Measurements, or periodically, regardless of whether any Input Measurements have changed.
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| − | | |
| − | <!--T:17-->
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| − | If Rule is set to run periodically ('''Polling'''), you must specify how often a Rule is executed by setting '''Intervals''' in seconds.
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| − | | |
| − | == Misc == <!--T:18-->
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| − | === Name and Description ===
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| − | A Rule also has a Name and Description. The Name and Description allows you to describe the event or situation that the Rule detects, such that recipients of the Rule's alert/notification knows exactly what happened and is able to react to it accordingly.
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| − | * The Rule's Name is displayed in the CMS' list of Rules. | |
| − | * The Rule's Name and Description is displayed in the Dashboard.
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| − | | |
| − | <!--T:19-->
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| − | You can also embed the value or tag of '''Input''' metrics in the Description. The syntax is the same as embedding in the content of an '''Action''', as described [[#Content_of_Actions|here]].
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| − | | |
| − | <!--T:20-->
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| − | Description is also the default content of an '''Action'''. You can describe the event or situation once in the Description, and reuse the information in all the Actions of the Rule.
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| − | | |
| − | === Severity === <!--T:21-->
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| − | You can also set the severity of the Rule. Default severity is '''Critical'''. Severity allows users of the Dashboard to filter '''Alerts''' by severity and attend to more severe '''Alerts''' first.
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| − | | |
| − | == Detailed Example == <!--T:22-->
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| − | The event that you would like to be notified about is potential fire in a building.
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| − | There are temperature sensors throughout the building. When a reading from any temperature sensor exceeds 60°C, a fire has probably broken out near the sensor.
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| − | You would like to be notified by email of such an occurrence.
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| − | | |
| − | <!--T:23-->
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| − | * The '''Input''' in this example would be the metric and measurement that readings from temperature sensor is sent to. e.g: <tt>iot_temperature_sensor_v1.temperature</tt>
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| − | * '''Condition''' is <tt>iot_temperature_sensor_v1.temperature > 60</tt>
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| − | * '''Action''' is email, with body text:
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| − | :<tt>"Potential fire detected in room: ${iot_temperature_sensor_v1.room}. Temperature in the room is ${iot_temperature_sensor_v1.temperature}°C"</tt>
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| − | | |
| − | <!--T:24-->
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| − | With the above '''Rule''' configured, when <tt>iot_temperature_sensor.temperature</tt> goes from 59 to 61, an email will be sent with the body text:
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| − | :"Potential fire detected in room: #03-00. Temperature in the room is 61°C"
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| − | | |
| − | <!--T:25-->
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| − | Note: "room" is a Tag of the <tt>iot_temperature_sensor_v1</tt> measurement that indicates which room the sensor is in.
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| − | | |
| − | == Constructing Condition == <!--T:26-->
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| − | This section will guide you to construct a condition using the Rule Editor when adding/editing a Rule in the CMS. The objective here is to tell Senfi how to detect the event or situation that you wish to be notified of.
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| − | [[File:rule_editor.png|thumb|Rule Editor|link=]]
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| − | The Rule Editor is a graph based "Drag and Drop" editor. Each node in the Editor represents either an '''Input''', Data Transformation, Logic, or an '''Action'''. Arrows are used to link the nodes and control the flow of data between nodes.
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| − | [[File:rule_editor_input_output_arrows.png|thumb|Input & Output of a node|link=]]
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| − | '''Arrows coming into the left of a node indicates the node's input, <br>and arrows going out the right of a node indicates the node's output'''.
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| − | | |
| − | <!--T:27-->
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| − | The graph must always start from '''Input''' nodes and ends in the '''Result''' or '''Action''' nodes (Data originates from '''Input''' nodes, is transformed by Data Transformation, Logic nodes, and is consumed by '''Result''' & '''Action''' nodes).
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| − | | |
| − | <!--T:28-->
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| − | ;'''Input''' nodes
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| − | :'''Metric''' - outputs the value/s of a metric. can be set to output the last known value, or a range of historical values
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| − | ;Logic Nodes
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| − | :'''Compare''' - comparison operators. e.g. <, >=, ==, !=
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| − | :'''Logic''' - perform "AND" or "OR" between 2 or more boolean values
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| − | ;Data Transformation nodes
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| − | :'''Filter''' - used to filter a range of values and output a subset number of values. Can only be used after a Metric node in "Range of Value" mode and before an Aggregate
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| − | :'''Aggregate''' - used to aggregates a range of values into a single value. E.g. sum, average, median. Can only be used after a Metric node in "Range of Value" mode
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| − | :'''Function''' - value-wise transformation. Transform each value, e.g ABS, Floor, Round etc. Can be used after a Metric node and before a Compare node. Outputs the same number of values as its input.
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| − | ;Result node
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| − | :'''Result''' - '''Result''' node. Must have 1 and only 1 node. Specifies the '''Result''' of a '''Rule'''
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| − | ;Action nodes
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| − | :'''Action''' - '''Action''' node. Input must always be from the "Result" node. Can have 0 or more "Action" nodes. Instructs Senfi to do something when '''Result''' changes.
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| − | | |
| − | === Basic Steps === <!--T:29-->
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| − | <!--T:30-->
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| − | # Drag a node above working area into the working area to create a node.
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| − | # Create "Metric" nodes, one for each '''Input''' metric.
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| − | # Select the correct measurement and metric for each "Metric" node. Read: [[#Configuring_Nodes|how to configure a node]]
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| − | # (Optional) If you need to compare metric value against a constant value, use the "Constant" node.
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| − | # Create "Operator" and "Logic" nodes to construct necessary logic
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| − | #* logic graph should output a single boolean (true or false) value
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| − | #* output from "Metric" node must go to input of a "Operator" node.
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| − | #* "Operator" and "Logic" nodes can be nested.
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| − | #* You can attach more than 2 inputs to a "Logic" node
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| − | # Create a "Result" node and attach output of logic graph as its input
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| − | # Create "Action" nodes, one for each desired '''Action''' and attach output of "Result" node as its input
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| − | # Save when done
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| − | | |
| − | === Example === <!--T:31-->
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| − | [[File:rule_editor_example.png|center|Example 1|thumb|700px|link=]]
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| − | Example 1: A simple Rule detecting when a Lift has tripped (safetyTrip == 1).
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| − | [[File:rule_editor_example2.png|center|Example 2|thumb|700px|link=]] | |
| − | Example 2: Detects when a Lift tripped (safetyTrip == 1), AND passengers are trapped in the Lift (load > 0)
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| − | | |
| − | === Working with historical values === <!--T:32-->
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| − | When historical values is required to detect an event, the "Range", "Filter" and "Aggregate" nodes are needed.
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| − | | |
| − | <!--T:33-->
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| − | By default, a "Metric" node will output the Last Known value of the metric. To obtain historical values of a metric, attach the output of "Metric" node to the input of a "Range" node. The output of the "Range" node will be historical values from the metric.
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| − | <!--T:34-->
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| − | The configuration options of the "Range" node allows you to change the range of historical values to output. E.g: You can configure it to output metric values from 1 hour ago till now, or the last 10 received metric values.
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| − | | |
| − | <!--T:35-->
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| − | After obtaining the list of historical values, you can:
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| − | * Filter the list using the "Filter" node.
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| − | * Transform each value in the list using the "Function" node.
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| − | The "Filter" and "Function" nodes can be nested.
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| − | | |
| − | <!--T:36-->
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| − | Finally, the list of historical values must be aggregated using the "Aggregate" node before its output can be used by a "Logic" or "Operator" node.
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| − | | |
| − | === Example using historical values === <!--T:37-->
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| − | [[File:rule_editor_example_historical.png|center|Historical Example 1|thumb|700px|link=]]
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| − | The example above detects when a Lift is stopped at Level 2 for over a minute.
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| − | | |
| − | === Configuring Nodes === <!--T:38-->
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| − | Each node contains attributes & options which you can modify. To modify the attributes of a node, move your mouse over the node and click on the "Gear" button that appears near the top right corner of the node (Beside the "X" button). A window will popup to allow you to configure the node.
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| − | | |
| − | ==== Aggregate node ==== <!--T:39-->
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| − | This section explains what each of the options for "Aggregate" node does.
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| − | ;sum
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| − | :the sum of all input values
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| − | ;count
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| − | :the number of input values
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| − | ;average
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| − | :the average of input values
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| − | ;median
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| − | :the median value of input values
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| − | ;max
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| − | :the largest value
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| − | ;min
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| − | :the smallest value
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| − | ;mode
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| − | :the value that appears most often
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| − | ;range
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| − | :the difference between the largest and smallest value (max - min)
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| − | ;stddev
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| − | :[https://en.wikipedia.org/wiki/Standard_deviation standard deviation]
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| − | ;percentile
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| − | :[https://en.wikipedia.org/wiki/Percentile percentile]. This option accepts an additional "Percentile Value" parameter.
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| − | ;every
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| − | :outputs true if every value fulfills the condition. This option accepts an additional "Condition" parameter.
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| − | ;any
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| − | :outputs true if at least 1 value fulfills the condition. This option accepts an additional "Condition" parameter.
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| − | | |
| − | ==== Function node ==== <!--T:40-->
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| − | This section explains what each of the options in "Function" node does.
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| − | ;abs
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| − | :absolute value
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| − | ;round
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| − | :round to nearest integer
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| − | ;ceil
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| − | :round up
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| − | ;floor
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| − | :round down
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| − | ;map
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| − | :This option accepts an additional "function" parameter. Using the custom "function" parameter, transforms each input value
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| − | <!--T:41-->
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| − | <span class="right">[[Computed_measurement|Next: Computed Measurement]]</span>
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| − | | |
| − | </translate>
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| − | | |
| − | === Pre-requisites === <!--T:1-->
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| − | A rule requires design and logical programing in order for it to work correctly. If this is your first time creating a rule, please read [[Rule|this guide]] first.
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| − | <!--T:2-->
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| − | You should also be familiar with the basic [[Measurement|measurements]] and its concepts. Please read [[Concepts#Measurement.2C_Metric.2C_Tag|this section]] if you require a refresher.
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| − | <!--T:3-->
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| − | You should
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| − | * Know what event the Rule should detect.
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| − | * Know what you would like Senfi to do ('''Action''') when the event is detected
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| − | * Have already created the '''Input''' measurement & metrics.
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| − | * Know the thresholds or values which indicates occurrence of event.
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| − | * Be able to send records to '''Input''' measurement & metric.
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| − | * (Optional) Be able to send simulated records to '''Input''' measurement & metric (to simulate occurrence of event or situation)
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