ABB REC 561, User Manual, Page: 538 / 643

Measurement of alternating
quantities
ABB Network Partner AB
1MRK 580 159-XEN
Page 7 - 19
Version 1.0-00
1.3 Continuous
supervision of the
measured quantity
The actual value of the measured quantity is available locally and
remotely. The measurement is continuous for each channel separately.
But the reporting of the value to the higher levels (control processor in the
unit, MMI and SCS) depends on the selected reporting mode. These
reporting modes are available:
• Periodic reporting
• Periodic reporting with dead-band supervision in parallel
• Periodic reporting with dead-band supervision in series
Users can select between two types of dead-band supervision:
• Amplitude dead-band supervision(ADBS)
• Integrating dead-band supervision (IDBS)
1.3.1 Amplitude dead-
band supervision
If the changed value—compared to the last reported value—is larger than
the ±
∆
Y predefinied limits that are set by users, and it this is detected by
a new measuring sample, then the measuring channel reports the new
value to a higher level (Fig. 2). This limits the information flow to a mini-
mum necessary.
Fig. 2 Amplitude dead-band supervision
After the new value is reported, the new +
∆
Y limits for dead-band are
automatically set around it. The new value is reported only if the meas-
ured quantity changes more than defined by the new +
∆
Y set limits.
1.3.2 Integrating dead-
band supervision
The value of the measured quantity is updated—even if the changes do
not exceed the amplitude dead-band supervision limits. The measured
value is updated if the time integral of all changes exceeds the pre-set lim-
its, see Fig. 3. The shadowed areas represent the time integrals which
exceed the pre-set value of the integrating dead-band supervision.
1 2 3 4 5 6
Y
t
∆
Y
∆
Y
∆
Y
∆
Y
Y1
Y2
Y3
new values reported
(x80159-2)