Bruno Wittmer

Hello, you might want to have a closer look at the International Standard IEC 61724 "Photovoltaic system performance monitoring - Guidelines for measurement, data exchange and analysis". You will find there useful information on monitoring the irradiance. The sampling interval for the irradiance is specified to be 1 min. or less, so I would say you sampling interval of 15 min. is too large. The standard also explains how to integrate or average your data according to the sensor and value you are measuring. If you want to measure hourly data that you want to import in PVsyst, the values should be representative for the hour that follows the time label. If for example you measure a value for 15:00, it should reflect the data from 15:00 to 16:00. For minimizimg your statistical errors, you need to keep the sampling interval small. To keep systematic errors small you should carefully calibrate your sensors and measure at a place that is representative for your whole array. If you can afford a redundant measurement this will also reduce the uncertainties. The standard also gives guidelines on how to check the quality of your measured data.

Dear nick, the export to clipboard functionality has some size restrictions that were important for some very old MS Windows versions. To get around this limitation you can export to files instead of the clipboard. I have just tried it for PVsyst 6.12 and it did work for the following two cases: Beginning date 01/01/13 12h00, Time Step 1 day: produces a file with a table for the whole year with values at 12h00 for each day. Beginning date 01/01/13 . Time Step 1 hour: Produces a file with a table for one month with values for every hour. The interface is not very user-friendly, PVsyst is not always keeping my last choices in memory. Especially the time ranges when generating the table and when exporting(!) are jumping back to default values, so please pay a lot of attention to these fields when exporting your files. I guess this part needs some cleanup for one of the next releases.

Dear nick, you can do this by selecting "Tools" in the Main Window and then "Table/graphs of solar parameters". Choose the location for which you want to generate the data. Go to the tab "Tables" and select "Sun's Height" from the list of variables. Choose a Beginning Date (for example 01/01/13 12h00). Choose as time step of 1 day and click on "Table". You will get the table with H Sol at 12h00 for each day of the year. You can export the table to the clipboard or a file. Note that if you want to get hourly values, the size limit for the table is one month, so if you want hourly values for the whole year you have to generate the tables for all 12 months separately. Best regards, Bruno