IAN HANBY - CHARTERED ENGINEER

INTELLIGENT WINDVANE

Please note that this instrument has been phased out and replaced by the Microcontroller Intelligent Windvane

For use in wind-directional sampling

CONTENTS OF KIT

  • Windvane

  • Mounting arm

  • Fixing bracket

  • 10-metre cable

  • Allen key, 2.5mm

  • Trimmer

  • Instructions




BENEFITS

  • Can be used to convert conventional air samplers into directional instruments

  • Time hysteresis characteristics prevent frequent output switching in turbulent airflows

  • Low current consumption allows battery operation over long periods

  • LED output allows quick and accurate adjustment of acceptance angle

  • Longer cable or extension cables available for certain applications

  • Fixing bracket allows mounting arm to be fastened to standard television aerial mast components

  • Spares, repairs or modifications always available

OPERATING PRINCIPLE OF THE WINDVANE


The windvane consists of a conventional vane/pointer system mounted on a 6mm diameter stainless steel shaft running in a pair of acetal bearings. This shaft drives a precision potentiometer capable of continuous rotation. The electronic system consists of a window detector, clock pulse generator and a series of programmable synchronous binary counters with associated logic gates. When the device is powered up, a count of 127 is placed in the registers. If the window detector sees a signal from the windvane within a pre-settable window, the clock pulses are counted upwards. If the count reaches 256, the windvane sets the output to +5 volts. If the window detector sees a signal outside the window, the clock pulses are counted downwards. If the count falls to zero, the windvane sets the output to 0 volts. If the status of the windvane changes before the count reaches 256 or zero, the count direction changes but the output will not change until the count finally reaches 256 or zero. The clock pulse generator is set such that the counter takes approximately 30 seconds to perform an uninterrupted count from zero to 256. The windvane also sends an output to drive an optional external low power LED, which indicates the current status of the vane, i.e. inside or outside the window. The window, or acceptance angle, is initially set at ±30°, but can be reset by the user within the range ±0° to approximately ±90°.


SPECIFICATION

  • The rotational life of potentiometer 10 million cycles mechanical

  • Input voltage 5v DC (Max 7v)

  • Input current approx 5mA + output current

  • Output voltage 5v DC

  • Output current 20mA max

  • LED output to suit HLMP4740 (2mA forward current)

  • Acceptance angle ±0° to ±90° (user adjustable)

  • Minimum output status duration 30 seconds (manufacturer resettable)

OPERATING PRINCIPLES AND SETTING-UP PROCEDURE - CLICK HERE

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