Getfield, Read – Echelon OpenLNS User Manual
Page 271
OpenLNS Programmer's Reference
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GetField
Summary
Gets a
object containing one field if the
object contains a structure.
The AutoWrite property of the returned DataPoint is set to
False; therefore, the Write method must be called explicitly to
write the information to the network variable.
The number of fields in a DataPoint object can be determined
from the FieldCount property. The name of a field can be
determined by that field's FieldName property.
Availability
Local, full, lightweight, and independent clients. Note that
some objects containing this property are not available to
Independent clients.
Syntax
dpField = dpObject.GetField(indexName)
Element
Description
dpField
represents the data point field requested in
dpObject
indexName
The index number or name of the data
point field to be returned.
Added to API
LNS Release 3.20.
Read
Summary
Updates the Value, RawValue, and FormattedValue
properties with the current value of the data point’s source
object. You can use either of these properties to read and
write to the data point’s value; however, they are formatted
differently. See these individual properties for more
information.
After the Read method is called, OpenLNS will update the
value of these properties to match the value of the data
point’s source object. For example, if the data point was
obtained through a network variable, the network variable
will be fetched from the network, and the three properties
would be updated to match the value reported by the physical
device on the network. This will ensure that the data point
returns a current value for its source object.
If the AutoRead property is set to True, OpenLNS will call
the Read method automatically each time you read the
RawValue, FormattedValue, or Value properties.
Availability
Local, full, lightweight, and independent clients. Note that
some objects containing this property are not available to
Independent clients.