Vaisala DMT152 - Manual (Page 60)

User's Guide _______________________________________________________________________
58 ___________________________________________________________________ M210865EN-F
4. Check and adjust the environment settings if prompted. You can
change the pressure compensation value (only needed for ppm
calculation) and the molar mass of the measurement gas. The
pressure must be entered in bar
a
; to enter the value in psi
a
, use the
serial line. For more information on these settings, see the
following sections:
- Set Pressure Value for ppm Calculation on page 46
- Set Molar Mass for ppmw Calculation on page 47
5. After a brief delay, the DMT152 should provide an approximate
measurement reading of the selected quantities. Remember that it
takes up to 15 minutes for the transmitter to start the active
measurement. If the desired quantities are not shown on the
display, select them from the Display – Quantities and units
menu.
6. The Auto power off function should be disabled on the MI70
indicator to prevent the indicator from powering off in the middle
of the check. While waiting for the active measurement to start,
check the setting in the Settings - User Interface menu, and
change if necessary.
7. Write down the Td reading after the measurement has stabilized.
8. Turn off the MI70 indicator and disconnect the DMT152.
9. Insert the reference probe to the measurement environment, and
connect it to the MI70 indicator.
10. Turn on the MI70 indicator. Check and adjust the environment
settings if prompted.
11. Wait for the reference probe to provide a stable reading, and
compare it with the reading from the DMT152.
The difference between the readings will give you an indication of
the approximate drift of the DMT152 and its need for calibration.
As a general rule, the reading from the DMT152 should be within
±4 °C T
d
of the reading from the reference probe.
NOTE Some notes on using the MI70 indicator with the DMT152:
- If you disconnect the DMT152 while the MI70 indicator is on, the
quantities measured will remain on the screen, but no measurement
will be shown.
- The messages from the transmitter (such as the supply voltage
error) will appear in English even if the MI70 has been set to
another language.