ABB ret650, Technical Manual

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99000529.vsd
Y
t
Value Reported
(1st)
Value Reported
Value Reported
Y1
Y2
Y3
D
Y
D
Y
D
Y
D
Y
D
Y
D
Y
Value Reported
IEC99000529 V1 EN
Figure 193: Amplitude dead-band supervision reporting
After the new value is reported, the ±ΔY limits for dead-band are automatically set
around it. The new value is reported only if the measured quantity changes more than
defined by the ±ΔY set limits.
Integral dead-band reporting
The measured value is reported if the time integral of all changes exceeds the pre-set
limit (
XDbRepInt ), figure 194 , where an example of reporting with integral dead-band
supervision is shown. The picture is simplified: the process is not continuous but the
values are evaluated with a time interval of one execution cycle from each other.
The last value reported, Y1 in figure 194 serves as a basic value for further
measurement. A difference is calculated between the last reported and the newly
measured value and is multiplied by the time increment (discrete integral). The
absolute values of these integral values 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 integral dead-band supervision is particularly suitable for monitoring signals with
small variations that can last for relatively long periods.
1MRK 504 135-UEN A
Section 14
Monitoring
431
Technical manual