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PSI 10000 4U Serie
3.10.15.5 Day trend
The so-called day trend is a special simulation mode for long-term tests. It processes a curve consisting of up to
100,000 user-definable points. For every processed point on that curve, the PV curve is calculated anew.
Every point is defined by 3 values of which one is the dwell time. When defining long dwell times the day trend
curve can be supported by an interpolation feature which can be optionally activated. It will calculate and set in
-
termediate points between two succeeding curve points. Hence it should be considered to run the day trend with
or without interpolation.
The day curve points have to be loaded into the device, either from a CSV file on USB stick or via digital interface.
The user selects the number of points according to the requirements of the simulation.
Formats of the CSV files to load from USB stick when manually configuring the function:
• For mode
DAY E/T
(required file name format: PV_DAY_ET_<arbitrary_text>.csv)
Column A =
Index
An ascending number between 1 and 100,000 (the first empty
index will cause the simulation to stop)
Column B
=
Irradiance
(E) in W/m²
Allowed range: 0...1500
Column C =
Temperature
(T) in °C
Allowed range: -40...80
Column D =
Dwell time
in milliseconds (ms)
Allowed range: 500...1.800.000
• For mode
DAY U/I
(required file name format: PV_DAY_UI_<arbitrary_text>.csv)
Attention! The values in columns B and C are real values which must not exceed the ratings of
the device or the device will neglect to load the file.
Column A =
Index
An ascending number between 1 and 100,000 (the first empty
index will cause the simulation to stop)
Column B
=
Voltage U
MPP
in V
Allowed range: 0...rated output voltage of the device
Column C =
Current I
MPP
in A
Allowed range: 0...rated output current of the device
Column D =
Dwell time
in milliseconds (ms)
Allowed range: 500...1.800.000
The number format and the column separator in the CSV files is determined by the regional
settings of the PC or the software used to create the files. The format must match the selection
for the device setting “USB file separator format” in the General Settings menu of the device,
else the device would neglect loading the file. For example, an american Excel should by default
use the dot as decimal separator and the comma as column separator, which would match the
selection “USB file separator format =
US
”.
3.10.15.6 Interpolation
The interpolation feature can calculate and set intermediate steps when running the PV function in day trend mode,
i. e.
DAY E/T
or
DAY U/I
. The calculation is always done between to succeeding points on the day trend curve. The
dwell time of every curve point is adjustable between 500 and 1,800,000 milliseconds (see above, format of the
day trend data file). While there are no extra points calculated when using the minimum time of 500 ms, following
applies to higher dwell time definitions:
•
The number of intermediate steps is determined from the dwell time and spread as equally as possible, where
any of the steps can have its own dwell time between 500 and 999 ms
•
The intermediate steps also respect the slope between the current and the next day trend curve point and thus
every step also includes a corresponding value alteration
