Where a source data field is likely to vary in length and it is only a sub-string of another field, you should create a separate data field in the source for each of the sub-strings (PREFIX, MEASURED VARIABLE, FUNCTION TYPE, and so forth).
For example, the source table may contain the following tags (the instrument type is indicated in bold type):
108 FT100
108 ICP100
108 FT100
108 ILP100
In this case the data field in bold type varies in length according to the tag. Therefore, you need to create a separate data field for each of the parts of the instrument type, for example:
108 FT 100
108 ICP 100
108 FT 100
108 ILP 100
If you have defined a fixed-name string as a prefix, you do not have to link source data to this part of the naming convention. The Import Utility will create this part automatically during the import process.