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Based on the calculation in this example, a value of 20 % is calculated for the error sum. In this
manner, the current difference of 0.5 A, which equates to a deviation of 10 % of the mean value, is
added to the total for each query interval of 5 minutes, until the error sum of 20 % is reached. In this
example, the error value is reached after two polling intervals. The Sunny Central Control displays
the warning "SMU".
If a string fails, the current difference in the above example is 4.5 A, which equates to a deviation
of 90 % from the mean value. If the settings in the above example remain the same, i.e. tolerance
at 10 % and tripping time at 10 minutes, the error sum of 20 % is already reached after the first
polling interval of 5 minutes. The Sunny Central Control now displays the warning "SMU".
On the basis of this example and the calculation formula, the sensitivity of the string current monitoring
can now be set by using the two parameters tripping time and tolerance. The parameters for String
Current Monitoring can be set via Sunny Central Control or the Sunny Data Control software.
8.3 Setting the Parameters Using Sunny Central Control
8.3.1 Setting the Number of Strings per Measuring Channel
The number of strings per channel is freely selectable for the 8 measuring channels. The default setting
is "1". The maximum number of strings per channel is limited to 4.
The optimal allocation for a measuring channel is intended to be 2 strings, nevertheless one can,
depending on the system design, connect more strings in parallel outside the Sunny String-Monitor
and append them to a measuring channel (see chapter 2.2 "Parallel Connection of
Strings", page 10).
TIP:
In the submenu No. of Str. All you can assign all channels of the Sunny String-Monitor to a string
number of 1 to 4. This avoids having to set the number of strings for each of the individual channels,
since this is automatically set for all the individual channels.
No strings in a measuring channel
• If there are no strings connected to a measuring channel, assign this channel to the
0 group (see chapter 8.3.2 "Setting the Groups", page 52).
Technical Description
8 Function of the String Current Monitoring
SSM-TEN103132
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