Network variable monitor point options – Echelon LNS User Manual

Page 215

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LNS Programmer's Guide

201

If you do not want a monitor point to use those default options during a

particular monitoring session, you can change the options that will be used
by writing to its

CurrentOptions

. All changes made to the

CurrentOptions

property take effect immediately. However, when the

monitor set is closed, these changes will not be saved as the default options to
be used the next time it is opened. The default options for each monitor point

must be maintained using the

DefaultOptions

properties.

NOTE: For permanent network variable monitor points, the default values
for some options properties (ServiceType, Retries, Priority) are

controlled by the connection description specified when the monitor point is

created. This is described in more detail in Table 9.1 in the next section.

Network Variable Monitor Point Options

The previous section of this document described the different ways to access an
NvMonitorOptions object, and how each one affects a monitor set or individual network

variable monitor point. To recap, you should follow these steps when setting the

monitoring options for your network variable monitor points:

1. Set the defaults for the monitor set by writing to the

NvOptions

property

of the

MonitorSet

object. The following code sample sets the default

values for the

ReportByException

,

GenerateInitialFetch

, and

PollInterval properties.

Set NvMonitorPointOptions = MySet.NvOptions
NvMonitorPointOptions.ReportByException = True
NvMonitorPointOptions.GenerateInitialFetch = True
NvMonitorPointOptions.PollInterval = 5000
Set MySet.NvOptions = NvMonitorPointOptions

For descriptions of the properties of the

NvMonitorOptions

object, see

NvMonitorOptions Object on page 202.

2. If you do not want a network variable monitor point in the set to use the

default options established in step 1, you can change its default options

by writing to its

DefaultOptions

property. Note that these changes will

not be applied to a monitor point that is in an open monitor set until the
monitor set is closed and re-opened.

Echelon recommends that you set the DefaultOptions property in the

same transaction that you create the network variable monitor point

whenever possible. The following code sample sets the default values for
a network variable monitor point’s

ResetPollingIfUpdated

and

SuppressPollingIfBound

properties.

Set NvMonitorPointOptions = MonitorPoint.DefaultOptions
NvMonitorPointOptions.ResetPollingIfUpdated = True
NvMonitorPointOptions.SuppressPollingIfBound = False
Set MonitorPoint.DefaultOptions = NvMonitorPointOptions

NOTE: Because temporary monitor points are only used in a single client

session, their

DefaultOptions

are not accessible. If you attempt to

acquire the DefaultOptions property through a temporary monitor
point, the LCA:#161 lcaErrNotAllowedOnTemporaryObject

exception will be thrown. All temporary monitor points will be enabled
with the default options selected in step 1.

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