Kippzonen BSRN Scientific Solar Monitoring System Uživatelský manuál stáhnout pdf (Strana 60)

the radiometer dome by sand or by hyrdometeorites such as hail. If the dome is damaged,

it should be replaced with one made of the same optical material. The change should

be documented and the dome kept for future reference. Although domes do not normally

change the overall calibration of the system, the instrument with the new dome should

be monitored for any differences, particularly changes in directional responsivity.

(i) Pyrgeometers: Daily cleaning of the dome of the pyrgeometer should take place when

the other instruments are cleaned. Particulate residues should be removed using a

soft brush or gentle airstream. The dome can be wiped with a lint-free cloth. In cases

where material has adhered to the dome, a cloth moistened with deionized water can

be used.

(2) The radiometer should be checked for any condensation on the inside surface of the outer

dome. If this occurs, the outer dome must be removed in a clean, dry location, cleaned and

the cause for the leak determined. The most probable cause is poor maintenance of the desiccant

(see weekly maintenance). If the desiccant has been changed within a week, the probable

cause is a poor ‘O’ ring seal. A replacement is required. If moisture is found on the inner surface

of the inner dome, the instrument should be replaced with a spare instrument and the faulty

instrument sent for service.

(3) The colour and the condition of the thermopile should be checked. If the colour is fading or

changing; or the thermopile surface appears rough, cracked or weathered; the instrument

should be removed from service and replaced with a spare. On newer instruments this occurs

rarely.

(4) The level of each horizontally mounted instrument (e.g., pyranometers, pyrgeometers) should

be checked and corrected as necessary. The bubble of the circular level should be completely

within the inner circle. For m ost instruments, this indicates that the instrum ent is level to within

±0.1°.

(5) The cabling leading from the instrument to the data acquisition system or junction box should

be inspected for wear. Unless the cable is to be replaced, or must be untangled, the instrument

should not be disconnected. All work on the cable should be appropriately documented. In

cases where a cable is functional, but aging, a time should be set for its replacement during

the station semiannual or annual maintenance (see below).

(6) The ventilator motors should be checked on a daily basis. If the m otor is not operating properly,

the problem should be corrected or the motor replaced. All procedures should be documented,

including the start and end time of the work. If knowledge of when the ventilator began to

malfunction is known (e.g., lightning strike) this should also be included in the log. On those

ventilators where the cover acts as a radiation shield, the top of the cover must be situated

below the receiver surface of the radiometer.

(7) The pointing of any instruments should be checked and, if necessary, corrected. The reasons

for possible misalignment are partially dependent on the type of tracker being used. The sun

must be shining to detect spot alignment for direct beam instruments; however, the checking

of clock times and general system failures is independent of weather conditions.

(i) One-axis solar tracker

- the solar declination must be checked and adjusted to align the solar spot with the

instrument target.

- as most one-axis trackers use synchronous motors, the power frequency must be

monitored to ensure that the tracker is being driven at the correct speed.

- the tracker must be inspected to ensure that no mechanical malfunction has occurred

(e.g., slippage in the clutch)

- In one-axis trackers, unless especially equipped, the cables attached to the instruments

must be manually unwound each day.

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Kippzonen BSRN Scientific Solar Monitoring System Uživatelský manuál Strana 60

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