Selection of Measuring Instrument during result recording

Dear Gurus,

During the result recording of MIC, I want to select the instrument which I am going to use for measuing the MIc.

Eg:

I am measuring the length of one Rod.

The MIC Length can be measured by Screw gauge, Vernier caliper , Micro meter or ruled scale .

So I have to select either one during result recording.

Please suggest me how to select or identify the instrument during result recording.

Thanks & Regards,

Srinivasan