Carel 2N Manuel D'utilisation page 46

Periodical verifi cation procedures
CAREL certifi es, with a paper included in the packaging ("Calibration certifi cate"), that the Datalogger was calibrated in the factory.
Nonetheless, as established by standard EN 13486, the instrument must be periodically tested to ensure the reliability of the data
recorded. Whatever the outcome of the verifi cation, this one must be noted down and kept. CAREL reports an example of forms
(see enclosures A, B and C). CAREL advises to follow the periodical verifi cation procedures here enclosed which generally follows
verifi cation procedures established by the normative law relevant to the CAREL Datalogger. For more details, please refer to the
laws in force in your Country.
Measurement instrument
Direct comparison by using a measuring apparatus, periodically tested with thermometer and multimeter checked and certifi ed by
SIT. Since the Datalogger is guaranteed with a precision of ±1.0°C, the error of the standard thermometer must be lower than
±0.2 °C, resolution 0.1.
Preliminary operations
• Make sure the Datalogger is not near devices that cause electromagnetic interferences.
• Make sure the probes, and the relevant cables, are not placed immediately near other cables of electronic
and electric devices.
• Clean the probe.
• Check the connections to the Datalogger, by making sure the Datalogger is carrying out the measurement
of the temperature.
Performance of the verifi cation
• Verifi cation should be carried out around the working temperature, keeping it constant as much as possible. It is absolutely
necessary to avoid excessive changes of the equilibrium of the system, once the verifi cation stage has been started (e.g. open
the door, to allow the compressor to start, switch on the light, ....).
• Place the calibrated thermometer as near as possible to the probe to be verifi ed, striving for an acceptable thermal coupling (e.g.
by constraining the two - probe and Datalogger - sensors , with thermoconductive materials such as copper).
• Note down periodically the temperature simultaneously read by the precision instrument and the Datalogger, noting
downnpossible modifi cations of the state of the system (e.g. stopped compressor, open door etc., so as to point out time
response, delay time, heat radiation, etc.).
Results of the verifi cation
If the difference between the value measured by the Datalogger and that of reference is:
• Lower than or equal to ±0.8° C , the outcome is acceptable.
• Ranging from -1.0 °C to -0.8 °C and from 0.8 to -1.0 °C, the outcome is acceptable, but the instrument must be verifi ed within 6
months.
• Lower than - 1.0 °C and higher than 1.0 °C: the outcome is negative.
If the verifi cation has a negative outcome, you can try to replace the Datalogger probe. If the Datalogger with a new probe proved
again to be out of precision, the instrument has to be returned to CAREL for a new calibration.
Important
The enclosures A and B of the manual are the masters to be photocopied at each verifi cation. The copies of the enclosures A and
B must be fi lled in and kept and represent the verifi cation report of the Datalogger instrument.
The enclosure °C is the life-cycle sheet. It collects the data of each verifi cation report. These documents do not replace the
calibration certifi cate issued by CAREL. CAREL can carry out, on request, the periodical verifi cation of the Datalogger for the
customers. Please contact CAREL after sales service.
APPENDIX