ABB REO 517 Applications Manual page 367

Monitoring of DC analog measurements
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The measured value is updated if the time integral of all changes exceeds the pre-set
limit (figure 192), where an example of reporting with integrating dead-band supervi-
sion is shown. The picture is simplified: the process is not continuous but the values are
evaluated at time intervals depending on the sampling frequency chosen by the user
(SampRate setting).
The last value reported (Y1 in figure 192) serves as a basic value for further measure-
ment. A difference is calculated between the last reported and the newly measured value
during new sample and is multiplied by the time increment (discrete integral). The ab-
solute values of these products are added until the pre-set value is exceeded. This occurs
with the value Y2 that is reported and set as a new base for the following measurements
(as well as for the values Y3, Y4 and Y5).
The integrating dead-band supervision is particularly suitable for monitoring signals
with low variations that can last for relatively long periods.
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