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LNS Programmer's Guide

216

Example of Explicitly Reading a Network Variable Monitor Point

To recap the previous discussion, follow these steps to explicitly read a network variable

value via a monitor point:

1. Create a monitor set on the device containing the network variables you

want to monitor, as described in Creating Monitor Sets on page 194.

Then, create a monitor point for each network variable you want to

monitor, as described in Adding Network Variable Monitor Points to a

Monitor Set on page 195.

2. Access the monitor set through the CurrentMonitorSets collection, and

then open and enable the monitor set. In this example, the doEnable

parameter supplied to the open method is set to True, so that the monitor

set is enabled as it is opened.

Set MyMonitorSets = MyNetwork.CurrentMonitorSets

Set MyMonitorSet = MyMonitorSets.Item(“Boiler Set”)

MyMonitorSet.Open(True, True)

3. Acquire the monitor set’s NvMonitorPoints collection, and access the

monitor points for the network variable you want to monitor.

Set MyNvMonitorPoints = MyMonitorSet.NvMonitorPoints

Set MyNvMonitorPoint =MyNvMonitorPoints.Item(“Pressure”)

4. Acquire a DataPoint object to use to explicitly read the value of the

network variable monitor point. Then, call the Read() method. LNS will

read the value of the network variable being monitored, and update the

DataPoint object’s value properties to match the current value.

Set MyDataPoint = MyNvMonitorPoint.DataPoint

MyDataPoint.Read()

Dim readValue as String

readValue = MyDataPoint.FormattedValue

NOTE: If the AutoRead property is set to True, you do not need to call

the Read() method in this step.

There are several ways your application can format the data stored in the DataPoint

object for display. For more information on this, see Data Formatting in page 241.

Example of Explicitly Writing a Network Variable Monitor Point

Follow these steps to explicitly write a network variable value via a monitor point:

1. Acquire the network variable monitor point you want to control, as

described in steps 1 through 3 of the Example of Explicitly Reading a

Network Variable Monitor Point scenario.

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Echelon LNS Bedienungsanleitung Seite 230