Verifi Cation Of The Internal Clock - Carel DLOGNTC015 Manual De Utilización

Verifi cation of the internal clock
The Datalogger records temperature and time. It periodically verifi es 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 fi nal 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 fi rst reading is 26" and the second is 27" the test can be plotted as follows:
Serial number: Installation date: Place:
Date Test duration Seconds of tot. error Resultant precision Result Operator signature
01/01/98 1h 3 0.083 yes ................................
CAREL guarantees that the clock has been calibrated at ambient temperature with a maximum error of 50ppm = 0.005%
(equivalent to 26' per year).