ABB RELION REX640, Техническое руководство, Страница: 1747 / 1960

The maximum percentage length of the potentiometer gap can be set with setting
Pot Max gap. The controller determines a gap length by measuring the distance
between both ends of a gap in ohms. A gap is indicated when the ohmic position
exceeds 2000 Ω.
If the coil potentiometer enters a gap during the normal operation, the controller
estimates the coil position based on its previous known position and coil movement
speed. If the actual gap length exceeds the setting
Pot Max gap or a new
gap appears during daily operation,
POT_ALARM
output is activated. Moreover,
TUNING_STS monitored data indicates the reason of alarm. High values of the
Pot
Max gap setting introduce inaccuracy to the coil movement as the coil position is
based on a calculated estimate. The purpose of the gap detection functionality is
to enable the controller operation even if the potentiometer is worn out during the
normal operation. The potentiometer should be replaced during the next service
break in order to guarantee accurate operation of the controller. The gap detection
functionality can be disabled by setting the
Pot Max gap value to 0. Potentiometer
gaps are illustrated in
Figure 930
.
Potentiometer
value [Ω]
Potentiometer
relative position [%]
Gap length
0 100
min
max
Figure 930: Potentiometer gaps
9.11.9 Signals
9.11.9.1 PASANCR Input signals
Table 1592: PASANCR Input signals
Name Type Default Description
IRES SIGNAL - Residual current
U3P SIGNAL - Three-phase voltages
URES SIGNAL - Residual voltage
Table continues on the next page
1MRS759142 F Control functions
REX640
Technical Manual
1747