Vaisala WMT700 - Manual (Page 91)

Chapter 4 ________________________________________________________________ Installation
NOTE Always use cables that meet the minimum dimension requirements. Long
cables with thin wires cause power losses in the cable and significantly
decrease the heating capabilities of WMT700.
Loop resistance of 0.15 Ω results in approximately 1 V drop in heating
voltage with 200 W heating. You should note this to get proper heating
capability. For example, the loop resistance of a 10 m cable (227568SP)
is 0.7 Ω resulting in an approximately 4 V drop. It is recommended that
you use at least a 28 V supply for the maximum heating capability.
Upgrading from WS425 to WMT700
When upgrading to WMT700, you have the following installation
options:
- Basic installation procedure, which consists of mounting
WMT700 with the FIX70 mounting kit and the WMT700
mounting adapter.
To upgrade to WMT700 according to this procedure, uninstall
the WS425 wind sensor and mounting kit and follow the
installation instructions in section Installation on page 57.
- Retrofit installation procedure, which consists of mounting
WMT700 with a WS425 mounting kit and the WMT700
mounting adapter for FIX30/60.
At the measurement site, you need to mount WMT700 and
connect it to the power source and data acquisition system.
After upgrading to WMT700, it is possible to install the optional
bird prevention kit available for the wind sensor. For more
information, see section Bird Cage on page 31.
WARNING To protect personnel (and the wind sensor), install a lightning rod with
the tip at least one meter above WMT700. The rod must be properly
grounded, compliant with all local applicable safety regulations. Do not
install the wind sensor above the top of the lightning protection rod.
WARNING Do not install WMT700 when there is a risk of thunderstorm or lightning
activity in the area.
VAISALA ________________________________________________________________________ 89