Trend Alarm Process

NI InsightCM™ SDK 3.3 Help

Edition Date: December 2018

Part Number: 375191F-01

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This process monitors trend alarm rules by evaluating their trigger expressions. If an expression changes from clear to set or vice versa, this process reports the change to the alarm instance to NI InsightCM Server and requests that the device collect data when the data set passes to the Data Event Creator process.

The application software prompts this process to evaluate alarm rules in two ways:

  • Evaluating the features, spectral bands, and single-point values whenever a data set is transferred from the previous process in the Dataflow Script.
  • Evaluating all registered alarm rules every thirty minutes.

This process evaluates alarm rules on the device. Users can also create alarm rules in the InsightCM web application that can be evaluated only on the server, and this process ignores them.

Actions Performed

  • Every time a process invokes the Dataflow Script for a data group, this process evaluates all the alarm rules associated with any channel measurement the device performs, regardless of whether a channel is in that data group.
  • Every thirty seconds, this process evaluates all registered alarm rules that are not part of the Dataflow Script data set. For example, this is when the process evaluates alarm rules for channel states.
  • This process receives updates from the NI InsightCM Server when users add or update alarm rules in the InsightCM web application.
  • This process informs NI InsightCM Server about alarm rules the device creates so they can be displayed in the InsightCM web application. For example, processes that acquire data create alarm rules that evaluate the status of each channel from which they acquire.
  • When the connection between device and server comes online, this process compares the alarm rules stored on the device with the alarm rules stored on the server and adds any new rules from server. This process also requests that NI InsightCM Server update itself with any rules from device.
  • This process buffers information about transitions an alarm instance makes from set to cleared and vice versa. If the connection between the device and server is offline at the time the transition occurs and the information cannot read the server, this process resends the information when the connection is reestablished.

Role within the Dataflow Script

When the Dataflow Script API sends a ProcessDataFlowBlock message to this process, this process requires the following inputs and produces the following outputs.

Inputs

  • The point value map sent with the Dataflow Script message contains feature and spectral band values that are common conditions for alarm rules.

Outputs

In the following situations, this process writes a CollectFileReason point whose string value is Alarm and writes a CollectFile point whose value is 1:

  • An alarm rule expression that previously evaluated to false now evaluates to true for the duration of the On Delay property configured for the alarm rule.
  • An alarm rule expression that previously evaluated to true now evaluates to false for the duration of the Off Delay property configured for the alarm rule.

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