Delmhorst Instrument F-2000T - Manual (Page 3)

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accumulated readings. Hence, the user must release the key before four seconds if
he wants to retain the readings. However, if all 100 readings are accumulated, then
he should keep the key pressed to erase the readings so that the meter can
accumulate the new ones.
6. TO CHECK THE METER CALIBRATION
To check the meter calibration, the user must PRESS first the “READ” key,
immediately followed (within one second) by the “CHECK” key. The meter should
display “12.0” +/- 0.2. Since a relay disconnects the external input when checking
calibration, there is no need to disconnect the external electrode.