If WMT700 is not able to measure the wind, it indicates a missing reading in the output. The most common reasons for measurement problems are ice, birds, or other foreign objects on the line of measurement.
When the WMT700 profile is used, WMT700 indicates missing readings by showing 999 in the data messages.
When the WMT700 data message 22 is polled, missing readings are indicated with the following response:
$999.00,999.00<cr><lf>