ABB Relion 670 series, Technical Reference Manual, Page: 904 / 1232

zero point clamping might be overridden by the zero point clamping used for the
measurement values within CVMMXU.
Continuous monitoring of the measured quantity
Users can continuously monitor the measured quantity available in each function block
by means of four defined operating thresholds, see figure
452 . The monitoring has two
different modes of operating:
• Overfunction, when the measured current exceeds the High limit ( XHiLim ) or High-
high limit ( XHiHiLim ) pre-set values
• Underfunction, when the measured current decreases under the Low limit
(
XLowLim ) or Low-low limit ( XLowLowLim ) pre-set values.
X_RANGE is illustrated in figure 452 .
en05000657.vsd
X_RANGE= 1
X_RANGE = 3
X_RANGE=0
Hysteresis
High-high limit
High limit
Low limit
Low-low limit
X_RANGE=2
X_RANGE=4
Y
t
X_RANGE=0
IEC05000657 V1 EN
Figure 452: Presentation of operating limits
Each analog output has one corresponding supervision level output (X_RANGE). The
output signal is an integer in the interval 0-4 (0: Normal, 1: High limit exceeded, 3: High-
high limit exceeded, 2: below Low limit and 4: below Low-low limit). The output may
be connected to a measurement expander block (XP (RANGE_XP)) to get
measurement supervision as binary signals.
The logical value of the functional output signals changes according to figure 452 .
The user can set the hysteresis ( XLimHyst ), which determines the difference between
the operating and reset value at each operating point, in wide range for each measuring
channel separately. The hysteresis is common for all operating values within one channel.
Section 15
1MRK505222-UUS C
Monitoring
898
Technical reference manual