SMA POWER PLANT CONTROLLER - Manual (Page 58)

13 Appendix SMA Solar Technology AG
58 PPC-BE-P7-en-13 Operating Manual
The range between x0 and x1 refers to the converted values. This range is dependent on the measurement signal used
and on the analog input to which the converted values are supplied.
The range between y0 and y1 is the range into which the Power Plant Controller scales the converted values. This is
equivalent to the measurement range.
Within the measurement range is the range in which the valid measured values occur. The lower valid measured value
corresponds to yMin, the upper valid measured value corresponds to yMax
Measurement signal Analog input Measurement range of
the analog signals
Range of the converted
values
Standard signal voltage Onboard ‒10 V
10 V
x0 = ‒8,192
x1 = 8,192
Standard signal voltage Onboard 0 V
10 V
x0 = 0
x1 = 8,192
Standard signal current Onboard 0 mA
20 mA
x0 = 0
x1 = 7,367
Standard signal voltage Bus coupler ‒10 V
10 V
x0 = ‒32,768
x1 = 32,767
Standard signal voltage Bus coupler 0 V
10 V
x0 = 0
x1 = 32,767
Standard signal current Bus coupler 4 mA
20 mA
x0 = 0
x1 = 32,767
Example: Scaling of analog input values
Analog voltage signals in the range from ‒10 V to +10 V are received at the analog input. The analog-to-digital
converter of the Power Plant Controller uses this to generate a digital signal in the range of ‒8.192 to +8.192. The
measured value processing in the Power Plant Controller calculates the reactive power value from this signal, and then
limits it to the permitted range from ‒15 MVAr to +15 MVAr.
Lower value for the range of valid measured values:
yMin = ‒20 MVAr Upper value for the range of valid measured values:
yMax = +20 MVAr
Lower signal value supplied by the transducer:
x0 = 8.192 Upper signal value supplied by the transducer:
x1 = 8.192
Lower value of the measurement range:
y0 = ‒15 MVAr Upper value of the measurement range:
y1 = +15 MVAr