Chapter 6 ______________________________________________________________ Maintenance
VAISALA ______________________________________________________________________ 213
11. The repaired measurement unit must be mounted in the same way
as described in sections Mounting Receiver Measurement Unit on
page 124 and on page 114.
12. Make sure that the enclosure is parallel with the support unit.
13. Secure the fastening screws of the measurement unit carefully.
14. Turn on the AC power switch (and also the battery backup switch,
if installed).
CAUTION
After repairing the measurement unit, fine alignment and calibration
must be carried out to establish normal operational conditions. For
details, see sections Fine Alignment on page 231 and Calibration on
page 232.
15. Re-install the measurement head cover and lock it carefully.
16. Close the interface unit and mount the upper interface unit cover
after fine alignment and calibration is finalized.
Replacing Window Transmitter Module
LTL212
The measurement units of the LT31 transmitter and receiver are equipped
with identical window transmitter modules LTL212. In case of a faulty
window transmitter, the optics unit has to be removed from the
measurement unit to access the window transmitter. The procedure is
identical for the receiver and transmitter measurement unit.
NOTE
To replace the window transmitter module LTL212, the measurement
unit has to be opened. For this reason, it is highly recommended to
dismount the complete measurement unit and carry out the replacement
work on a clean workbench in a dry room.
To remove the complete measurement unit, first the AC power has to be
switched off and then the measurement head cover has to be removed.