User`s guide

Chapter 3 ______________________________________________________ Functional Description
VAISALA _______________________________________________________________________ 33
Host System Connections and Interfaces
WMT700 always needs a host device for measurement data collection
and presentation. The host device is usually an automatic weather station,
but other host devices such as data loggers or personal computers can
also be easily used.
WMT700 performs calculation, quality control, and data format
procedures on the measurement data. The processed data is sent to
weather stations using serial ports and/or analog output channels. The
most commonly used communications interface is RS-485, but WMT700
has a flexible set of interfaces ranging from RS-232 to voltage and
current mode analog signals.
WMT700 can be set to send measurement data as either analog output or
data messages via serial port or both outputs can be used simultaneously.
Operating and configuring commands are sent to WMT700 through the
serial interface.
Operation and heating power are usually provided from one single power
supply. Separate power supplies for the heating and operations can also
be used to prevent the heating function from consuming the operations
power. In a split-supply system there can be a separate backup power
supply for the operations power supply.
Figure 10 on page 34 shows the main software components and external
interfaces of WMT700.