When the unit detects invalid equation parameters, it will generate an error, light the ERR annunciator
on the front panel, and will not use the new parameters. Instead, it will operate with the last valid
settings. Therefore, although it may seem that the unit is operating correctly, it will NOT be using the
values that you have programmed for SAS mode.
Curve Restrictions
Under certain conditions, such as if Imp is significantly less than Isc, the model equations will exhibit a
certain degree of inaccuracy in that the actual maximum power point (Pmp) and value may be
somewhat different from the expected value of Pmp (Imp x Vmp). Thus the actual Pmp point may not
occur at exactly the Imp x Vmp. This can be corrected by entering new values for Imp and Vmp.
Note that the accuracy specifications in SAS mode are relative to the values given in the exponential
equations, and not necessarily to the input parameters Imp and Vmp. However, the Isc and Voc values
are always accurately given by the exponential equations.
Programming a Table
Output synchronization is NOT provided in Table mode; this means that the output will
activate a table as soon as the command is received. You cannot synchronize table
changes between outputs or mainframes. There is also no list support for table changes
In Table mode, the output characteristic is determined by a user-defined table of I-V points as
illustrated in the following figure. Table mode operation is achieved by sampling the output voltage,
applying a low-pass filter, and continually adjusting the constant current loop by using the filtered
voltage as an index into the stored table of points.
Linear interpolation is used to set the current when the filtered voltage does not have an exactly
matching table entry. What this means is that the I-V curve is generated by connecting the points in
the table by straight lines. The more points that you provide, the more accurate the curve will be when
the points are connected.
Keysight MP4300 Series Operating and Service Guide 81
4 Using the Modular Power System
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