Meteo Database > Import meteo data > Custom meteo files

(go directly to our Notes on Meteo)

The conversion protocol window holds several tabs, and includes a sample view of your source file, where you can follow step-by-step the effects of your choices.

General Tab

Defines the general file organization (separator, time step of your data, lines to be skipped).

When choosing the proper separator the display sample file will be organised in field columns.

Date format tab

Date recording mode, please choose among:

-	Reference year: your source data are well organized in a yearly sequence, from January 1st, not leap year. In this case the program does not need reading the dates nor writing them on the file. This is suitable for clean TMY or DRY files.

Sequential dates, not read on the file:
your source file is still a clean sequence of records, but not necessarily starting from January, 1st, and of any duration (one year maxi). Therefore the program can only memorise the beginning and end dates, it doesn't need to read nor to write dates on files.

Dates read on the file:
If your data sequence is not very clean (some holes), the program should read the dates, and write them on the target file. This option displays a variety of date formats, including the field separator, as well as specific date separators (for example h, '/' or ':' for hour:minutes), which may all be meant as 'non numerical' characters. Dates can hold month and day numbers, or day-of-year.

This option even allows to read specific measured data daily files, where the day number is not included in the record, but only in the file name (to be used in conjunction with the "Chaining" facility). When reading dates on the file, you should specify the corresponding fields on the record. The program asks for each date field, and displays the corresponding labels on the columns.

Time base :

The time base of your data will usually be Legal Time. The program leaves the possibility of solar time (but it is hard to imagine that someone will record data in this mode, as he will have to adjust the clock periodically) or Universal Time.

Summer timer :
PVSyst proposes an option to convert records written in summer time mode to winter time mode (which is the standard mode of PVSyst *.MET files).

First line time interval:

In your dataset a line of data may stand for the beginning of the interval or for the end of the interval. You have the possibility to specify if in this part of the dialog. But in many cases you won't know it. In this situation, let the checkbox to "Interval beginning (for daily data)" or "0..1" (for sub-hourly data). PVSyst will give you to define properly the shifts as discussed just below.

Shifts to apply on dataset:
The conversion process is an iterative process. You will first do the import, consider the feedback given by PVSyst in terms of time-shift, if necessary define the shifts to apply on the dataset and re-import.
If not properly defined, the hourly records will be shifted of half-an-hour or one hour, and solar geometry will not act properly, especially for transposition. The final result can be checked using daily profile meteo plots: on these plots you can ask for superimposing the "clear day" profile on your data. When choosing good days the model curve should be centered on your hourly data.

Meteo variables (meteo files)

This lets you choose what is on the data file (irradiation, temperature, wind).

For each chosen parameter, you should specify:

- the field order in the record; the label will appear on the corresponding field on the sample file display.

- the unit choice for the variable, has to correspond to the kind of data you are importing.

- the multiplying factor to be used in order to obtain the chosen unit (e.g. if you have values of irradiance from a data-logger in V / W/m²).

With the fixed width fields option, you can displace the separator columns with the mouse.

When using Global on tilted plane, you should specify the plane orientation.

Measured variables (measured data files)

For a given system type, the program proposes the parameters likely to be measured, each of them being of course part of the simulation parameters.

As above, you should choose the available parameters, their field order and multiplying factor.

Gathering fields (measured data files only)

In many data acquisition systems you can have several measurements corresponding to a single global simulation variable. For example:

- when dealing with several PV-fields, the measurements are often recorded for each field. But as PVsyst will treat this as one only system, the currents and energies should be added, and the voltages perhaps averaged (not a very good idea…).

- if you have current and voltage measurements, for computing the power (energy) at each step.

- for averaging several module temperature sensors.

Therefore you can gather the data of several source channels in one only target internal variable. This can be performed using sum, product or average operator.

After defining the number of gathered fields desired for each variable, you will have to specify the column of each fields.

Chaining files

- One only file: the usual case.

- Manual chaining: at the end of the file, the conversion process asks the operator for the next file, to be written on the same internal data file.

- One file per day: the file names - DOS names restricted to 12 characters - should include day and month identifiers in a specified coded format. Then the conversion will automatically chain the daily files.

- One file per month: as above, for monthly files.

Conversion of meteo file - Defining import format file

Conversion of meteo file - Defining import format file

Chaining files