SA2005P
ssaammeess
Recalculate the rated conditions
Krx = 642 000 / Rated volt / Rated current / 6400 x 3600 x
1000 / 512 x (1 + %MinError / 100 )
Krx = 642 000 / 230 / 80 / 6400 x 3600 x 1000 / 512 x 1.015
Krx = 38.9077
Kr = 38 - 1 = 37
The 37 are stored in the rated register.
The channel balance values are adjusted to make provision for
the rounding error.
Gain = ((Krx - Kr +1 ) / Krx ) x 100
Gain = (( 38.9077 - 38 ) / 38.9077 ) x 100
Gain = 2.33
The channel balance pre-devider value must be recalculated.
(BMIN will be the lowest %error value, in this case 1.5%,
CHB1, CHB2 and CHB3 are the individual phase %errors
measured.
Cb1 = (CHB1 - CBMIN + Gain ) x 256 / 100
Cb1 = (1.5 - 1.5 + 2.33 ) x 256 / 100 = 5.97 =5
Cb2 = (CHB2 - CBMIN + Gain ) x 256 / 100
Cb2 = ( 5.2 - 1.5 + 2.33 ) x 256 / 100 = 15.43 = 15
Cb3 = (CHB3 - CBMIN + Gain ) x 256 / 100
Cb3 = (3.2 - 1.5 + 2.33 ) x 256 / 100 = 10.316 = 10
Store the calculated values in the EEPROM and the meter is
calibrated.
11/16
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