WALKER P296 Page 1 of 3
COMBINED WIND SENSOR
GENERAL
The unit consists of a combined masthead unit incorporating wind speed and wind direction
sensors, which are used to provide serial data of wind speed and wind direction.
This unit consists of two distinctly different sections; an upper vane unit and a lower cup unit
assembly.
A] Cup Unit.
The unit carries a cupset fitted to a stainless steel shaft, which runs in shielded bearings. A cap
fitted to the shaft provides a labyrinth for protection against water ingress. The slotted end of the
shaft, driven by the cupset rotates within an opto-switch carried on the lower pcb of a board
assembly mounted within the carrying tube. Twice per revolution of the cupset, a square wave
signal is produced which is fed directly to a microcontroller. The processor times the duration
between successive pulses and, by using a stored look-up table, appropriate for the cupset
concerned, the wind speed value is calculated.
B] Vane Unit.
This unit carries a vane assembly fitted to a stainless steel shaft, which runs in shielded bearings.
The vane cap forms a labyrinth for protection against water ingress. The vane is attached by two
set screws diametrically opposite through the cap itself. The lower end of the shaft, driven by the
vane, carries a circular magnet, which rotates above hall-effect sensors mounted on the upper
pcb of the assembly mounted within the carrying tube. Signals produced as the vane rotates to
take up a position determined by the wind are fed directly to a microcontroller for calculation of
wind direction.
The sensor, attached to a stainless steel arm and block assembly, is provided with a mounting
bracket suitable for securing onto the horizontal surface of the mast top. Two fixing slots are
provided in the base of the mounting bracket to allow for final alignment.
The unit transmits a NMEA 0183 sentence as follows:
• $WIMWV,x.x,R,x.x,N,A*hh<CR><LF>
• Note that both wind direction and wind speed fields are variable to xxx.x
© John Lilley and Gillie Ltd. Ref: P296/ds/ra/022 Issue 3
WALKER P296 Page 2 of 3
COMBINED WIND SENSOR
INSTALLATION
Refer to drawing 3343-2-30 for outline of the P296 Combined Wind Sensor.
The unit should be mounted as high as possible in air which is undisturbed by movement over
and around any structures and in a position to ensure a clear azimuth. For shipborne use, fitting
high on the main mast is recommended as under adverse sea state conditions there would be less
possibility of the sensor being frequently washed with sea water than if mounted forward.
The Masthead Mounting Bracket (A) must be securely fastened to the mast top using machine
screws, self-tapping screws or pop rivets. Note that hexagon head set screws are recommended
as these will more readily allow for tightening after final adjustment is made to ensure correct
alignment. Make sure that before drilling the mast top, the Mounting Bracket (A) can lie fore
and aft, and that there is room for the Main Unit (B) and for its connecting P293 cable assembly.
Ensure that the Mounting Bracket (A) is correctly aligned; so that the Main Unit points directly
forward, towards the bow of the vessel, before finally locking the bracket into position by
tightening the screws concerned. Slots in the base of the mounting bracket allow for this
adjustment. Note that the sloping top edges of the mounting bracket are to the rear.
Having visually aligned the Mounting Bracket (A), sufficiently tighten the securing screws used
to hold the bracket in position. Re-fit the main unit (B); the combined wind sensor, arm and
block assembly, and secure, using the four M5 pozi-pan head screws and lock washers (C)
provided; two on each side of the bracket. With the P293 cable assembly connected, hold the
vane steady, as if the vessel is “head to wind”, and check with bridge personnel that the reading,
on the fitted analogue or digital wind display, is 0º. If necessary, adjust the position of the
mounting bracket until the required result is achieved. Lock the mounting bracket in position
when correct alignment has been achieved. If the combined sensor is not going to be fitted
immediately ensure that the connector of the P293 cable assembly is protected from the elements
until such time as the P296 is fitted. The 4 core screened cable of the P293 is fed through the
mast using suitable synthetic rubber grommets top and bottom, or appropriate glands. If the
cable is brought down the mast externally, it should be secured at regular intervals to prevent
chafing. Leave enough slack cable at the mast top to allow the connector to be attached and to be
removed from the P296 main unit (B).
If the P296 is to replace an earlier Walker combined masthead unit, it is likely that an original
Walker mounting plate is fitted directly to the mast top. This flat plate will be found to contain
two threaded studs, protruding vertically, which will align with the slots in the P296 mounting
bracket (A). The nuts and washers, attached to these studs, must be removed and the mounting
bracket (A), with the main unit (B) attached, positioned over the studs, and the washers and nuts
re-fitted.. The P296 must then be correctly aligned, fore – aft, as described above, before locking
it securely in position on the fitted mounting plate using the nuts and washers concerned.
On installation, always ensure that the P293 connector is securely mated.
Always check the installation to ensure the sensor is not affected by other equipment operating
locally, which may not conform to current standards, e.g. radio/radar transmitters, engines,
generators etc.
Guidelines:
• Avoid mounting in the plane of any radar scanner – a vertical separation of at
least 2m should be achieved.
© John Lilley and Gillie Ltd. Ref: P296/ds/ra/022 Issue 3
WALKER P296 Page 3 of 3
COMBINED WIND SENSOR
• Radio transmitting antennas; the following minimum separations (all around) are
suggested:-
• VHF IMM – 1m
• MF/HF – 5m
• Satcom – 5m (avoid likely lines of sight)
• Ensure that the system is correctly connected and that if a junction box is used
ensure that cable screens are connected through to maintain EMC integrity.
If part installation is carried out with either only the sensor assembly or the down cable assembly
being fitted then it is important to protect the appropriate connector from the elements until it
can be mated with its other half.
If the P296 sensor is removed at any time, ensure that the in-line connector attached to the P293
cable is suitably protected from the elements until such time as the sensor is refitted.
CABLING
For connection to other equipment, a P293 cable assembly is required. Refer to P293 Data Sheet.
MAINTENANCE
Cleaning:
If exposed to extreme low temperatures and precipitation causing a build up of ice, which may
prevent the rotation of the vane or cupset, the unit should normally be allowed to defrost
naturally. However, tepid water can be sprayed onto the unit to speed up the process if required.
Do NOT attempt to remove snow or ice with a tool.
Servicing:
There are no user-serviceable parts requiring routine maintenance.
In the event of failure it is recommended that all cables and connectors be checked for
continuity, bad contacts, corrosion etc. Check that both cupset and vane are able to rotate freely.
If it is necessary to remove the sensor unit at any time, first unscrew and release the P293 cable
connector from the back end of the P296 unit and protect the in line connector of the P293 from
the elements. Release and remove the M5 screws and lock washers from the sides of the
mounting bracket and remove the P296 main unit; the combined wind sensor, arm and block
assembly. Re-fit the screws and lock washers to the mounting block on the main unit for safe
keeping.
REFERENCES
Drawing 3343-2-30: Outline of P296 Combined Wind Sensor
P293 Data Sheet
© John Lilley and Gillie Ltd. Ref: P296/ds/ra/022 Issue 3
DRAWING No. SHEET 1 OF 2 PROJECTION
3343-2-30 NOTE:
WHEN FITTED THE MASTHEAD UNIT MUST
1
134 TURNING RAD OF VANE POINT DIRECTLY FORWARD. SLOTTED HOLES
ARE PROVIDED FOR FINAL ADJUSTMENT.
52.4
FIXING CRS
(6.7 wide SLOTS)
ANGULAR
2
ADJUSTMENT
FORWARD
15°
51
15°
3
ANGULAR
ADJUSTMENT MIN 80mm CLEARANCE
70 FOR CONNECTOR
4 MAIN UNIT (B)
327
FIXINGS SCREWS/S PROOF
WASHERS (C)
P293 CABLE
ASSY
6
MASTHEAD MOUNTING
BRACKET (A)
88 TURNING RAD
7 OF CUPSET
547
ISSUE DATE CHANGE No. ISSUE DATE CHANGE No. THIS DRAWING IS THE PROPERTY OF JOHN LILLEY & USED ON DRAWN DATE TITLE
8 GILLIE LTD AND IS SUBMITTED AS CONFIDENTIAL
P296 AMT
1 16/12/03 INFORMATION WHICH MUST NOT BE USED FOR ANY OUTLINE OF P296 COMBINED
PURPOSE OTHER THAN WHICH IT IS SUPPLIED. IT IS NOT
16/12/03
MATERIAL CHECKED BY
2 26/03/04 TO BE COPIED OR USED FOR THE PURPOSE OF WIND SENSOR
3 25/11/04 MANUFACTURE WITHOUT OUR AUTHORITY IN WRITING.
JOHN LILLEY & GILLIE LTD TOLERANCE FINISH SCALE DRAWING No. SHEET 1 OF 2
(INCORPORATING THOMAS WALKER & SON LTD)
9
37-41 BISSELL STREET
BIRMINGHAM, B5 7HR, ENGLAND
DIMENSIONS IN PATH
1:2 @ A3 3343-2-30
mm
A B C D E F G H I J K L
DRAWING No. SHEET 2 OF 2 PROJECTION
NOTE:
3343-2-30 M6 FIXINGS FOR MASTHEAD BRACKET (A)
1 TO BE PROVIDED BY CUSTOMER.
FIXINGS SCREWS/S PROOF
WASHERS (C)
MAIN UNIT (B)
FIXINGS SCREWS/S PROOF
WASHERS (C)
5
MASTHEAD MOUNTING
7 BRACKET (A)
ISSUE DATE CHANGE No. ISSUE DATE CHANGE No. THIS DRAWING IS THE PROPERTY OF JOHN LILLEY & USED ON DRAWN DATE TITLE
8 GILLIE LTD AND IS SUBMITTED AS CONFIDENTIAL
P296 AMT
1 16/12/03 INFORMATION WHICH MUST NOT BE USED FOR ANY
OUTLINE OF P296 COMBINED
PURPOSE OTHER THAN WHICH IT IS SUPPLIED. IT IS NOT
16/12/03
MATERIAL CHECKED BY
2 26/03/04 TO BE COPIED OR USED FOR THE PURPOSE OF WIND SENSOR
3 25/11/04 MANUFACTURE WITHOUT OUR AUTHORITY IN WRITING.
JOHN LILLEY & GILLIE LTD TOLERANCE FINISH SCALE DRAWING No. SHEET 2 OF 2
(INCORPORATING THOMAS WALKER & SON LTD)
9
37-41 BISSELL STREET
BIRMINGHAM, B5 7HR, ENGLAND
DIMENSIONS IN PATH
1:2 @ A3 3343-2-30
mm
A B C D E F G H I J K L
