This a Report Field macro used to make a calibration report number that auto-increments each time it is used. The macro will be inserted into a report template and each time the template is used to create a report, the macro will generate a calibration report number which is different from the previous time the template was used.
The scheme uses a text file to keep track of the previously generated number and then applies simple arithmetic to increment this number, saving the result to the text file. The mechanics of making this happen involve reading a value from the text file, and then writing an updated value back to the same file.
See the attached tutorial (.pdf file) for step by step instructions. A separate MS Word document is provided with the macro code to help simplify the copy & paste efforts.