Vaisala PTB330TS, User Manual

Page: 55 / 89

Chapter 4 ______________________________________________________________ Maintenance
VAISALA_______________________________________________________________________ 53
Calibrating and Adjusting
Temperature
1. Check that the MI70 indicator is connected to the HMP155, and
turn it on. Set the correct time, date, and environmental settings
(pressure compensation) if prompted.
2. Uncover the adjustment buttons on the HMP155 probe by
removing the protective cover and removing the calibration seal.
Refer to
Figure 22 on page 51 .
3. Activate the adjustment mode by holding down the
ADJ
button on
the probe.
4. Press
OK
to move on to the adjustment and select T or T
a
as the
quantity you want to adjust. Only one of them is shown; if you can
select T, it means you do not have the additional temperature
probe.
5. Insert the probe into a known reference environment:
- If you are calibrating and adjusting
T
, insert the HMP155
probe in the environment.
- If you are calibrating and adjusting
Ta
, insert the additional
temperature probe in the environment, and ignore the main
HMP155 probe.
6. Wait for the reading to stabilize, and compare the reading with the
reference. If the reading is not within the stated accuracy of the
HMP155, continue this procedure to adjust the measurement. If the
reading is accurate, exit the adjustment mode by pressing the
Back
button, then the
Exit
button.
7. Press the
Adjust
button and select 1-point or 2-point calibration. If
a
Cannot adjust
message is displayed, press
OK
and try again.
8. Follow the instructions given on the display to finish the
adjustment.
NOTE
If your HMP155 has the additional temperature probe, you cannot
calibrate the temperature sensor on the HMP155 probe using the MI70
indicator. However, you can do so using the
CT
command on the serial
line. Additional calibration and adjustment methods are provided in
the HMP155 User’s Guide, which is available for download from
www.vaisala.com.