Omega UWBT Series, Руководство пользователя

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12-2
sensors that have been removed from the original packaging we recommend to
store them in ESD bags made of PE-HD8.
In manufacturing and transport the sensors shall be prevented of high
concentration of chemical solvents and long exposure times. Out-gassing of
glues, adhesive tapes and stickers or out-gassing packaging material such as
bubble foils, foams, etc. shall be avoided. Manufacturing area shall be well
ventilated.
A.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent vapors may offset the
sensor. The following reconditioning procedure may bring the sensor back to
calibration state:
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h.
(75%RH can conveniently be generated with saturated NaCl solution. 100 – 105°C
correspond to 212 – 221°F, 20 – 30°C correspond to 68 – 86°F)
A.5 Temperature Effects
Relative humidity reading strongly depends on temperature. Therefore, it is
essential to keep humidity sensors at the same temperature as the air of which
the relative humidity is to be measured. In case of testing or qualification the
reference sensor and test sensor must show equal temperature to allow for
comparing humidity readings.
The packaging of sensor is designed for minimal heat transfer from the pins
to the sensor. Still, if the sensor shares a PCB with electronic components that
produce heat it should be mounted in a way that prevents heat transfer or
keeps it as low as possible. Furthermore, there are self-heating effects in case the
measurement frequency is too high.
A.6 Light
The sensor is not light sensitive. Prolonged direct exposure to sunshine or strong
UV radiation may age the housing.
A.7 Materials Used for Sealing/Mounting
Many materials absorb humidity and will act as a buffer increasing response
times and hysteresis. Materials in the vicinity of the sensor must therefore be
carefully chosen. Recommended materials are: Any metals, LCP, POM (Delrin),
PTFE (Teflon), PE, PEEK, PP, PB, PPS, PSU, PVDF, PVF. For sealing and gluing
(use sparingly): Use high filled epoxy for electronic packaging (e.g. glob top,
underfill), and Silicone.
Out-gassing of these materials may also contaminate the sensor (see Section H.3).
Therefore try to add the sensor as a last manufacturing step to the assembly,
store the assembly well ventilated after manufacturing or bake at 50°C for 24h to
outgas contaminants before packing.
Appendix A
A