The Instruments

The Weather instrument

The Weather instrument simulates NMEA sentences for wind speed and direction, and water temperature.

The value of many input fields can be changed with the up-down buttons located at the right side of the input boxes, or typed directly into the input boxes. Note that decimals are ignored when using up/down buttons.

Observe that there is a choice of 2 sentence identifiers: $WI (Weather instruments) or $II (Integrated Instrumentation) in order to maintain compatibility between different manufacturers of this kind of instruments.

Operation

After clicking the "Start" button the Wind instrument simulation will start, and NMEA sentences will be sent to the selected serial port of the PC, until the "Hold" or "Exit and Save" buttons are pressed. Only those NMEA sentences are send that are checked in the "NMEA sentences" panel.

When the "Open Log file" option from the main "File" menu was selected, the sentences will also be written to the user selected logging file.

To view the sentences being sent select the "View trace window" option from the main menu.

Clicking the "Hold" button will suspend operation, until "Cont." is clicked. "Exit and Save" will exit the instrument and save all current values in the windows registry, so that next time the instrument is used it can continue where it stopped.

A short description of each field will follow below.

Wind speed
Can be given in knots, meters per second or kilometers per hour. You can optionally set a variation factor as a percentage of the wind speed. Wind speed will then vary randomly within the borders of the factor, to simulate a more realistic output.

Wind angle
The direction of the wind. 0-360. Relative or true. You can optionally set a variation factor as a percentage of the wind angle. Wind angle will then vary randomly within the borders of the factor, to simulate a more realistic output.

Water temperature
Water temperature in degrees Celsius. Output by the MTW sentence.

NMEA sentences panel
Tick the sentences you want to send, select the interval (0-59) and if you want a checksum calculated and added to the sentences or not.