V2/Concepts/Event

Event

Whenever Result changes (from true to false and vice versa), Events may be triggered. Events includes Actions such as sending of notifications, commands to systems or request to a webhook.

General Information

Name and Description

An Event has a Name and Description. The Name and Description allows you to describe the event or situation that the Expression detects, such that recipients of the Event's notification or Alarms knows exactly what happened and is able to react to it accordingly.

• The Event's Name and Description is displayed in the Alarm Description on the Digital Twin.

Description can also be 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 Event.

Inputs

You can define Inputs tags in the Event. These Inputs tags are linked to values or tag of input data coming from the related Expression. By doing so, you can embed the Inputs in the Description. You can learn more on how to embed the Input in the Description as described here.

Example

Using our Smart Weighing Scale measurement from earlier, the general information for one simple Event can be as follows:

• Name: Battery level low
• Inputs: weighing_scale_id, current_battery_level
• Description: Weighing scale $(weighing_scale_id) battery level is running low. Current battery level: $(current_battery_level)

Action

There are 3 types of content options available for Action, namely:

• Notification
• Command
• Webhook

Notification

Notifications such as Email, SMS and Telegram can be sent to personnel listed upon Event execution. You will be able to describe the event or situation that has happened to the recipient of the notification in the subject and message of a notification.

To further aid you in describing the event, you can embed the Event Input in the subject and message of a notification.

Take a look at this more detailed example.

Command

Commands can be sent to external system integrated with Senfi to directly control the sensors in the external system. E.g. Command sent to lift system to automatically make a lift call for a VIP upon arrival.

Webhook

Webhook request can be sent to external systems such as work order system via Webhook address. You can pass the required parameters in the message body of a Webhook.

Detailed Example

The event that you would like to be notified about is chiller malfunction in a building. There are chiller equipment to help power the air-conditioning in a building. When the status of a chiller shows that it has failed to run, the chiller probably has malfunctioned. You would like to be notified by email of such an occurrence, automatically switch on the backup chiller and issue a work order for maintenance repair.

• The Input in this example would be the metric and measurement that readings from chiller equipment is sent to. e.g: iot_chiller_v1.status
• Condition is iot_chiller_v1.status = failed to run
• Event: Chiller equipment malfunctioned
• Event Input is device_id and chiller_status
• Notification Action: Email, with body text:

"Chiller device no: ${device_id} has malfunctioned. Chiller status: ${chiller_status}. Please investigate.

"

• Command Action: Send command to backup chiller to turn it on.
• Webhook Action: Send webhook to issue work order for chiller maintenance repair.

With the above Expression configured, when iot_chiller_v1.status is equivalent to failed to run, an email will be sent with the body text:

"Chiller device no: 05 has malfunctioned. Chiller status: failed to run. Please investigate."

Note: "device_id" come from the Device ID Tag of the iot_chiller_v1 measurement that identifies a particular chiller.

Example

Example 1

Example 1: A simple Rule detecting when a Lift has tripped (safetyTrip == 1).

Example 2

Example 2: Detects when a Lift tripped (safetyTrip == 1), AND passengers are trapped in the Lift (load > 0)

Working with historical values

When historical values is required to detect an event, the "Range", "Filter" and "Aggregate" nodes are needed.

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.

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.

After obtaining the list of historical values, you can:

• Filter the list using the "Filter" node.
• Transform each value in the list using the "Function" node.

The "Filter" and "Function" nodes can be nested.

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.

Example using historical values

Historical Example 1

The example above detects when a Lift is stopped at Level 2 for over a minute.

Configuring Nodes

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.

Aggregate node

This section explains what each of the options for "Aggregate" node does.

sum

the sum of all input values

count

the number of input values

average

the average of input values

median

the median value of input values

max

the largest value

min

the smallest value

mode

the value that appears most often

range

the difference between the largest and smallest value (max - min)

stddev

standard deviation

percentile

percentile. This option accepts an additional "Percentile Value" parameter.

every

outputs true if every value fulfills the condition. This option accepts an additional "Condition" parameter.

any

outputs true if at least 1 value fulfills the condition. This option accepts an additional "Condition" parameter.

Function node

This section explains what each of the options in "Function" node does.

abs

absolute value

round

round to nearest integer

ceil

round up

floor

round down

map

This option accepts an additional "function" parameter. Using the custom "function" parameter, transforms each input value

Next: Computed Measurement