Operational Procedures - Taking Measurements - VWR DO220 Manuel D'instructions

5
7
8
O p e r a t i o n a l P r o c e d u r e s - T a k i n g
M e a s u r e m e n t s
Press to turn the unit on or off. When turned on, the instrument will
perform a self-diagnostic test during which an error message may
display. This is normal. After the self-diagnostic test completes, the
temperature displays in the lower right and the dissolved oxygen
measurement displays in the center of the display (figure 5). The unit is
ready for operation. If necessary, perform a 1-point dissolved oxygen
calibration. The digital instrument and probe can hold its calibration for
many months but should be verified regularly.
Immerse the probe into the sample solution to take a measurement.
When the unit is not in use, turn it off to save battery life. It is not
necessary to recalibrate the instrument after turning it off and back on.
The instrument has a 30 minute auto shut off feature when not in use.
Mode key. Adjusts between
measurement modes (%, mg/L),
recalling saved data (rCL) and
deleting saved data (dEL).
Enter key. Used to confirm
calibration, to save data from run
screen, to select data mode (rCL/
dEL), and confirm coefficient entries.
Sample/Mode key. Press and
hold for 3 seconds to switch
between continuous and manual
measurement modes. Press and
release to restart the measurement
when in manual mode. Continuous
mode: the instrument will
continuously update the dissolved
oxygen measurement. Manual
mode: the instrument will update
the DO reading until reaching a
stable measurement. The stable
measurement will be 'locked' on
the display until the user initiates
a new measurement reading by
pressing the Sample/Mode key.
7