Peter Bennett wrote:
On Wed, 26 Jan 2005 01:54:48 +0000, bing2005
wrote:


Can anyone please tell me how did the speed transducer of SPEED2100
measure the speed of the boat?
I try to design my own display unit for this speed tranduscer. However,
i dont know the operation of the speed transducer, such as how i
calculate and measure the speed through the paddle wheel of the
transducer. When the paddle wheel is moving, how i going to know the
speed of the boat?
If anyone know, please tell me.
Thanks a lot!!!


The paddlewheel speed sensors I've seen had a small magnet in the
paddlewheel, and a coil in the sensor body. As the paddlewheel turns,
the magnet passes by the coil and produces a voltage or current pulse
in the coil. To measure speed, you just count pulses/time.


And further to that, the number of ticks in a kilometer, mile, and
nautical mile are also known and that count and fractions thereof are
used to increment the log.

This kind of impeller does not compensate for current flow so there can
be some error in speed and distance reading because of that.

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)