Solar Forecast
Solar Forecast| This
function block outputs a forecast for the solar production.
The calculation is performed based on the installed
power, solar irradiation and orientation. To calculate the
solar position, longitude and latitude must be entered
(project settings) and the time must be correct. The generation factor and the cloud cover factor are no longer set manually but are learned automatically: the block continuously compares the forecast with the actual PV power (input PV current) and corrects itself. Both learned factors are provided as outputs for monitoring. Please note: Due to cloud formation and other factors it is impossible to predict the yield exactly. The calculated values can therefore never reflect reality exactly. |
Inputs |
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| FL |
Learning factor |
Learning rate of the learning function. Determines how
strongly new measured values influence the learning factors. A higher
value leads to faster adaptation, a lower value to more stable but
slower corrections. When generating the addresses, a variable is
created automatically for this input and connected. Value 0 (default): automatic — a learning rate suitable for most systems is used (0.1). Only enter your own value if you deliberately want faster or slower learning. Value range: 0.01 - 0.5 Recommended values: 0.05 - 0.1 = slow, stable learning - recommended for systems with consistent conditions 0.1 - 0.2 = medium learning speed - good compromise for most systems 0.2 - 0.5 = fast learning - for new systems or when conditions change frequently (e.g. growing vegetation, new shading) Example: At a learning rate of 0.1, 10% of the current measurement ratio and 90% of the previous factor flow into the new learning factor. |
| PV |
PV current |
Current total PV power of the system. This value is needed for the learning function and should be connected to the output of a PV inverter block or energy meter. Unit W or kW according to the parameter Outputs factor. |
Outputs |
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| +0 |
Today |
Forecast remaining yield of the current day.
Hours that have already passed are not counted, so the value
decreases during the day and approaches 0 in the evening. A comparison
with the inverter's daily meter in the evening therefore
inevitably results in a lower value. |
| +1 / +2 / +3 |
+1 / +2 / +3 day |
Forecast total yield of the next three days. |
| FE |
Generation factor |
Learned generation factor (system gain). Formed
automatically from the comparison of the forecast with the actual PV
power during clear hours and compensates for permanent
deviations (e.g. soiling, ageing, shading). 1.0 = no correction;
> 1.0 = forecast is raised, < 1.0 = lowered. Info output only, to
monitor the learning progress. |
| FB |
Cloud cover factor |
Learned cloud cover factor. Formed automatically
during cloudy hours from the actually observed cloud attenuation
and adjusts how strongly the forecast cloud cover reduces the yield.
1.0 = weather model unchanged; < 1.0 = clouds attenuate less than
assumed, > 1.0 = more. Info output only. |
Parameters |
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| Openweather | Optionally the weather forecast from Openweather can be used
for the calculation. This way the predicted cloud cover is included
in the calculation. Important: For this the function block "OpenWeather - Internet Weather" must be present in the project. |
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| Solar constant | Solar irradiation in watts per square meter (default 1361 W/m2). Optional adjustment of the solar irradiation; at high altitudes the irradiation can for example be higher. | |
| Outputs factor | Setting for the calculation in W or kW. Depending on the setting, the input PV current is also interpreted in W or kW. | |
| Debug | Outputs detailed calculation and learning messages in the program trace. Use only for commissioning and diagnostics. | |
| Strings | In this parameter the data of the PV system
is configured. Several PV strings can be configured in order to
take orientation and shading into account.
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