Carel DLOGNTC015 Manual De Utilización página 27

Verification of the internal clock
The Datalogger records temperature and time. It periodically verifies the temperature measurement and also
the precision of the internal clock. The maximum error permitted in the time measurement is 0.1% (equivalent
to 8h and 40' per year).
In order to test this, use a sample clock with an error lower than of 200 ppm. and note the seconds it indicates
the instant that the Datalogger display shows a change of minute.
Repeat this operation after at least an hour. The two second readings of the sample clock should not differ by
more than one second. In this case the test is passed.
The error range during these operations could in fact be considered not greater than 3 seconds (1s of error in
the initial second reading, 1s in the final one and a maximum of 1s of difference between the two sample
clock readings) on a measured total time of 3600 seconds (1h). In percentage, 3/3600 is an error lower than
the 0.1% required.
If the sample clock is a chronometer, the test is easier.
For example, if the first reading is 26" and the second is 27" the test can be plotted as follows:
Serial number: Installation date:
Date Test duration Seconds of tot. error
01/01/98 1h 3
Carel guarantees that the clock has been calibrated at ambient temperature with a maximum error of 50ppm
= 0.005% (equivalent to 26' per year).
Place:
Resultant precision Result Operator signature
0.083 yes ................................
48