How do instruments fit in? 
Revision log
| Date | Revision description |
| 2024-05-03 | Updated the diagram representing the model for a diiferential pressure flow transmitter. |
| 2024-04-21 | Added a diagram representing the model for a diiferential pressure flow transmitter. |
| 2022-10-20 | Changed the code listing to also include the alternative mapping method |
| 2022-10-19 | Editorial changes, added latest spreadsheet with 1270 subclasses of INSTRUMENTATION FUNCTION |
| 2020-07-19 | Added Detectors and Measuring Instruments |
| 2019-11-09 | Editorial changes, updated spreadsheet with 852 instances of INSTRUMENTATION FUNCTION |
| 2018-12-22 | Description extended, including a paragraph on the applicability of Possible Worlds |
| 2018-02-13 | Changed DEVICE into FUNCTION ; small corrections |
| 2017-06-19 | Completely updated in line with the RDL |
| 2016-09-11 | Added the latest spreadsheet with the top hierarchy and made a few corrections |
| 2015-12-17 | Removed the ISO 15926-4 XXXXXX classes (no longer in RDL) |
| 2015-10-23 | First issue |