Wika 70-8xx Manual de usuario descargar pdf (Pagina 12)

11472988.02 04/2013 GB/D/F/E

WIKA operating instructions expansion thermometer, model 70

7. Indicator check

Indicator checks should only be carried out in comparison with a more accurate

instrument or, if possible, with a calibrated instrument. The temperature during the check

must remain constant.

Fluctuating temperatures can lead to reading errors caused by the dierent response

times of the sensors.

With thermometers without thermowells, with a full and correct insertion length, a

minimum waiting time of 5 minutes must be maintained for temperature equalisation.

Temperature checks using thermometers with sensors assembled with thermowells can,

in many cases, only result in a reference temperature at the instrument under test, due to

permanent heat dissipation caused by the thermowell. In temperature applications tted

with static checking thermometers (e.g. pipeline systems), permanent osets in reference

temperatures can also be caused by the measuring path. Ambient temperatures around

the indicator case which dier substantially from room temperature can lead to steady

indication errors with constant ambient temperatures and to varying indication errors with

uctuating ambient temperatures.

Permanent indication errors caused by the ageing of the measuring system can be

ignored, as they only account for a fraction of the indication accuracy.

8. Zero adjustment

WARNING!

Any interference with or modication to the instrument will invalidate the

warranty!

A zero adjustment may only be carried out by the manufacturer or in adequately equipped

workshops by qualied persons.

 The electrical connection must only be made by qualied skilled personnel.

 Connection of the switch via terminal box

 Conductor cross-section max. 1.5 mm

 The terminal assignment is stated on the connection label of the thermometer

7. Indicator check / 8. Zero adjustment

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Wika 70-8xx Manual de usuario Pagina 12