changes in humidity in the range of tens of percent, even if the mean value
is correct. Moisture condensation on the freezer walls is common.
Recommendations for calibration
Metrological verification is carried out according to the requirements of the
application with intervals fixed by the user. Recommended calibration interval
is stated at
for each device type. According to legal
requirements at some applications, it may to be required, to be calibration
performed by an independent accredited laboratory.
Recommendations for regular checks
It is recommended to check the measurement chain to which the instrument
is incorporated at the regular base. Checking interval and inspection scope
depend on the appli
cation and the user’s internal regulations. Results of each
regular check should be recorded. Found problems should be addressed
accordingly according to their severity. In fixed installations following checks
are recommended to be performed:
•
Overall visual check of the device including cover integrity a condition of
connectors.
•
Check of the cabling and probes. It should be inspected cable
connections, cable surface integrity and proper cable routing (e.g.
installation of new high voltage or high current cables parallel to the device
cabling).
•
Check of all probes and sensing elements. Visual inspection for a water
ingress into probes. Check location where is probes placed with respect
to correct measurement conditions.
•
Functionality check of whole measurement chain (checking of features
utilized by the application):
a) Check whether measured values are as expected. Measured values
can be observed at device LCD display or device webpages.
b) Check whether measured values are properly transferred into data
acquisition platform like is ATAL Onlinesensor or ATAL Database. Data
are transmitted according to selected sensing interval.
c) Check history data inside data acquisition platform for any
unexpected data outage or alarm states.
d) Functionality check of alarming feature(s). This should be done by
changing the input quantity to give rise to an alarm. This alarm state
should be signalised at device LCD display and alarm email should be
delivered (if feature is used).