The Device Server Signal Interface

3. The Signal Properties


A set of signal properties is defined in the signal class. The properties must be defined for a device class. They are used for signal identification and the automatic configuration of monitoring and tuning applications and the history database configuration tool.

The properties of a signal object are:
Signal Properties
PropertyDescription
NameThe full signal name.
LabelA label for the signal value, which can be used in applications.
UnitThe unit of the signal value.
FormatThe format in which the data should be displayed (printf() format).
DescriptionA text describing the signal.
MaxA maximum value. Can be used for data display or to check limits of set values.
Min A minimum value. Can be used for data display or to check limits of set values.
AlHighAbove this limit an alarm will be indicated.
AlLowUnder this limit an alarm will be indicated.
DeltaIf the nominal value and the read value of the signal differ by +/- delta during the
number of seconds specified by "Delta_t" , an alarm will be raised.
Delta_tIf the nominal value differs from the read value for a longer time than Dta_t seconds,
an alarm will be raised.
Standard UnitA multiplier factor to convert the given signal unit into a standard unit (V, A, W, bar ...).


The Device Server Signal Interface - 27 FEB 1998

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