Short answer

First verify the run, device and date match, then check whether device memory holds data for that interval. If a file exists, the gap may be a download omission; if not, recording may not have occurred. If the device was discarded, the distinction may be impossible. Record the file ID and download time; do not label an unmeasured interval normal or an excursion.

For a blank run in the table, investigate: was its file not downloaded, or is there no measurement? They look alike, but the evidence differs.

Verify the match

Compare run date, device ID and form. Files before and after offer clues, but do not prove a record exists for the gap.

Check device memory

If available, follow the manual to check whether memory holds data for those dates. A file may mean download was skipped. If none appears, do not assume recording never started; check logging interval, device status and match.

Record evidence and uncertainty

Note device and file IDs, dates searched, checker, download time and result. If a single-use device was discarded, the distinction may be impossible; state that limit.

Separate the report entry

Separate measurement times from download time. Mark a missing file or interval as missing data; do not fill it with a normal value or excursion. If gaps recur, compare device handoff, download and file matching dates.

Recovery can vary

Memory capacity and overwrite behaviour depend on the model. Check its manual; preserve the device and available data for authorised download. No data does not reveal temperature during the interval, so refer product decisions to the quality process.

How to distinguish an undownloaded file from no recording