Specifications

AIRMAR

PB100 WeatherStation Technical Manual revision 1.007

where a is the current signed azimuth offset value, b is the current signed pitch

offset value, and c is the current signed roll offset value. All values are reported

to the nearest tenth of a degree.

The factory default value for all three parameters is 0.0 degrees.

The azimuth offset angle is used to adjust the apparent wind angle relative to the

bow of the vessel, and the vessel’s heading when using the internal compass.

These values are further used in calculating the true wind speed and angle.

The azimuth offset angle, along with the pitch and roll offset angles are also used

to adjust the reported pitch and roll values in the transmitted $WIXDR sentence.

A properly set azimuth offset angle will allow the unit to accurately report pitch

and roll of the vessel, even though the orientation mark on the sensor housing

may not be facing precisely toward the bow. The recommended procedure to set

these offsets is as follows:

1. If the unit is mounted on a vessel, this procedure should be performed with

calm water and no wind, and with the vessel at rest.

2. First, zero out all offsets by sending the command

$PAMTC,ATTOFF,SET,0,0,0.

3. Determine the desired azimuth offset angle, and program this into the sensor

using the command $PAMTC,ATTOFF,SET,a where a is the azimuth offset

of the sensor relative to the bow, in degrees. The pitch and roll offset fields

should be omitted for this step (or set to zeroes).

4. Allow the vessel to stabilize to its "level" state, and then read the values of

pitch and roll that are reported by the XDR sentence. If the vessel is rocking

back and forth, then take a number of readings and calculate an average for

both pitch and roll.

5. Program the negated versions of these measured pitch and roll values back

into the unit with the $PAMTC,ATTOFF,SET,,b,c sentence. For example, if

the XDR sentence reports an average pitch angle of 6.2 degrees, and an

average roll angle of -4.3 degrees, then you would send the sentence

$PAMTC,ATTOFF,SET,,-6.2,4.3 to the WeatherStation. Note that the

azimuth offset field in this sentence is a null field, indicating we are not

changing its value at this time.

6. At this point the transmitted XDR sentences should be producing values that

are centered around 0.0 degrees for both pitch and roll.

7. The programmed attitude offset values may be checked at any time by sending

the command $PAMTC,ATTOFF,Q to the unit; it will reply with

$PAMTR,ATTOFF,a,b,c.