ABB REB650, Technical Manual

Page: 246 / 504

Magnitude dead-band supervision
If a measuring value is changed, compared to the last reported value, and the change is
larger than the ±ΔY pre-defined limits that are set by user (
XZeroDb ), then the
measuring channel reports the new value to a higher level, if this is detected by a new
measured value. This limits the information flow to a minimum necessary. Figure
105
shows an example with the magnitude dead-band supervision. 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.
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 105: Magnitude 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 106 , 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 106 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
Section 12
1MRK 505 277-UUS C
Monitoring
240
Technical Manual