JSUP TAG CLASSES (BOZZA)
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Indice Argomenti

	  1. Why tag classes
	  2. Class properties
	  3. Custom tag properties


Tag classes are a useful way to define the
properties of JSup [tags]. Tag classes are
organized in a hierarchical tree structure where a
class inherits, adds and overrides the properties
of its ancestors. 1. Why tag classes Even if you
have not to assign particular properties to a tag,
it is a good practice to assign every [tag] to a
tag class: * It's a way to categorize [tags] and to
explain their meaning / usage. * If you later have
to assign properties to a category of [tags] it
will be a matter of seconds. * It's a way put
[tags] in groups that [JavaCode] can access at
runtime. For example to create [tasks] for the
[JSup scheduler]. 2. Class properties * Name: Must
be as descriptive as possible because this will be
the only info displayed in [Tag Dialog] (to see the
parentage the tree combo button must be opened).
The name must be unique within the parent class. *
Description: Only for later reference. * Path to: a
read only property that can be copied to be used in
[JavaCode] to access the tag class (getTagClass(
String path ) static method. * Numeric tags
properties - These properties will affect numeric
[tags] only: * Unite of measure: specify the
default UM of the tags (see [JSup UM support]). *
Initial numeric value: Enter the value the tag will
assume when the [application] starts and no
[retentive] value is available. * Change dead band:
since tag processing is driven by change events,
you can limit the minimum [tag] value variation
that will be considered a change. For changes
lesser than the given dead band no elaboration will
be performed (no screen update, no [code]
calculation, no [alarm] status update, etc). * Bit
field: see [JSup tag bit fields]. * Value min-max:
you can limit the range the belonging [tags] value
can assume. If a value greater than the given
maximum value is written to the tag, then the tag
value will be the maximum; If a value lesser than
the given minimum value is written to the tag, then
the tag value will be the minimum. * I/O raw value
min-max: the range of the value read from and
writter to remote I/O device (via [I/O hook]).
These values (with Value min-max or the defaults if
none) cause a tag value scaling on read/writes. If
raw min-max are not specified or are the same of
tag value min-max (or type default if none), then
the tag is not scaled on read/write. * Out of range
action: the behavior when out of raw range values
are read, if not specified the behavior for parent
class will be used, otherwise: * Force in range: if
the raw value is less than the raw min, the raw min
is considered instead of the read value. * Ignore
value: the value out of range is discarded and the
[tag] value is not changed. * Read error: the value
out of range is discarded and the [tag] value is
not changed and the [channel] read is considered
not successful (End read tag, if any, is set to
false). * Trend options: * Trend scale: A default
scale (min max) when a [tag] is added to a [trend].
* Trend color: A default color used when a [tag] of
this class is added to a [trend]. If the given
color is already used in the trend than a different
one will be automatically chosen. * Data logging
options: * Data log dead band: as the Change dead
band, but to limit the data logging. Only changes
lesser than the Data log dead band will not be
considered to write a new record for the tag. * Max
data log rate: a different way to limit the
frequency tag values will be written. If you enter
a value (in milliseconds) than no more than a
record every given ms will be written for a tag
belonging to the class. * Type of data log: When
you limit the log rate (with the previous
parameter), you can chose what kind of summary will
be written for the tag: * Max: only the maximum
value from the previous record will be written. *
Min: only the minimum value from the previous
record will be written. * Mean: the mean value from
the previous record will be written. * All:
Min/Mean/Max value from the previous record will be
all written. * String tags properties: * Initial
numeric value: Enter the value the tag will assume
when the [application] starts and no [retentive]
value is available. * Max (or fix) length: the
meaning depends of the [type] of the [tags]: *
String: it will be the maximum length of such tags.
* FLString: it will be the fixed length of such
tags. * Default property values: enter the values
(even localized) for the default properties for
[tags] belonging to this class (see [Using tag
properties]). 3. Custom tag properties Many tag
class properties can be specified directly by a tag
using its own properties in the [Tag Dialog]. Use
the buttons of the Custumize tag class settings to
define custom tag class properties for the tag. The
fact that a [Tag Class] property is customized
within the tag properties is shown by the
corresponding button (see the Initial value button
on the right).