Format File

The format file defines the import/export/linking rules. The file maps columns from the external data source format to the internal Plant SCADA database format. In other words, it determines what information is imported/exported/linked and how this information is modified during the operation.

The format file also provides the information to allow Plant SCADA to use the correct driver for accessing the external data source.

Some format files are provided with Plant SCADA; however, sometimes you might need to write or modify a format file using an editor such as Microsoft Notepad.

Following is an example of how format file rules work. (For more information, see Format File Layout.)

1. Column 3 in the external data source needs to be copied into the "Name" column in the Plant SCADA's tag database. (Plant SCADA names are restricted to alphanumeric characters (a to z, A to Z, and 0 to 9) and the underscore character "_", but this is not typically a consideration in the format file; Plant SCADA does the conversion automatically). However, if Column 3 in the external data source happens to be blank, there is no need to copy this record across (it needs to be rejected).

2. Column 1 in the external data source needs to be copied straight into the "Addr" column in Plant SCADA's tag database, because they both mean exactly the same thing.

3. Columns 4, 5, 6, and 7 in the external data source need to be copied into the "Comment" column in Variable.DBF. (It is not uncommon for external data sources to split the comments across several fields). The fields need to be copied in that order, so that if the data in Column 4 in the external data source is "Loop", Column 5 is "1", Column 6 is "Process", and Column 7 is "variable", these fields are copied across in order, so that the "Comment" column in Variable.DBF reads "Loop 1 Process variable". This process is called 'concatenation'. (For the "Comment" column, Plant SCADA automatically adds a space between each field from the external data source.)

4. The data in Column 1 in the external data source determines what Plant SCADA needs to write in the "Type" column. However the data cannot be copied across directly, because it would not make sense to Plant SCADA. Instead, it needs to go through a conversion (or filtering) process. This conversion needs its own set of rules, such as:

5. If Column 1 in the external data source is "BT%d:%d.%d" (where%d means "any decimal number"), Plant SCADA needs to write the string "DIGITAL" in the "Type" column.

6. If Column 1 in the external data source is "F%d:%d/%d" (where %d means "any decimal number"), Plant SCADA needs to write the string "DIGITAL" in the "Type" column.

7. If Column 1 in the external data source is "O:%e" (where %e means "any octal number"; that is, every digit from 0 to 7), Plant SCADA needs to leave the "Type" column blank. It still accepts the record (provided other columns pass any filtering tests) but it does not write anything in the "Type" column. The assumption is that Plant SCADA currently does not have (or does not need) a suitable corresponding type.

8. If Column 1 in the external data source is "PD%d:%d.%d", Plant SCADA needs to write the string "REAL" in the "Type" column.

9. If Column 1 in the external data source is "ST%d:%d", Plant SCADA needs to write the string "STRING" in the "Type" column.

10. If there are no rules covering the contents of Column 1 in the external data source, Plant SCADA needs to reject the whole record and not copy it into the Plant SCADA database.

See Also

Format File Layout