ABB RELION REX640 - Page 1746

Table 1591: Example of a linearization table
Potentiometer value (setting Pot value x, x =
1…10)
Coil position (setting Coil current x, x = 1…
10)
100 10
150 20
200 30
250 37
300 43
350 48
400 53
450 57
600 68
1000 90
200 400 600 800 10000
0
10
20
30
40
50
60
70
80
90
100
Potenometer value [Ω]
Coil posion [A]
Figure 929: Example of a linearization curve
Aged ASCs can suffer from wearing of the position-indicating potentiometer.
The potentiometer gaps are identified during the calibration and the number
of the gaps is displayed on the HMI after the calibration. Actual gap locations
GAP_LO_VAL_x and GAP_HI_VAL_x (x = 1…5, which corresponds to the gap
identification number) are visible in the Monitored data view. If the maximum
number of five gap locations is exceeded, the first pair is overwritten.
The coil position should be known and the controller operation should be
guaranteed even if no new calibration is done. When potentiometer gaps are
present in either both ends or in the middle of the potentiometer range, the
potentiometer should be replaced. These are the three critical points of the
calibration where ohmic measurements must be precise.
Control functions
1MRS759142 F
1746 REX640
Technical Manual