The notes on damping show the variety of how to get the job done.  A =
swing of 3.5 times past the equilibrium position sounds a lot "looser" =
than optimum.  In setting up a damping system, I would eyeball the =
action by displacing--say one cm, and watch the return to overshoot two =
mm, and settle to equilibrium again--or a 5 to 1 ratio was in the =
ballpark.  The standard check one can make is the "walk-up" test.  Walk =
up to the base perpendicular to the boom, stand for 20 seconds or so, =
and then back away----If all is well, there will be two traces--alike, =
but in opposite directions.
    As you walk up, the sensor moves slightly to a new equilibrium =
position.  The damping ratio or situation will show nicely---bearing in =
mind this is a velosity readout rather than a displacement--but close =
enough approximation to give us the damping condition quick & easy!!!
     I usually went for a 8 to 1 ratio.  I know with no damping, the =
boom swings forever from the energy of microseisms.  With critical =
damping, one kills most or all of the action,  The objective of damping =
is to remove the natural period or swing of the pendulum--but not kill =
it---and there is some leeway--------
                                                           Good =
damping---                Jim Lehman







The notes on damping show the variety of how =
to get the=20
job done.  A swing of 3.5 times past the equilibrium position =
sounds a lot=20
"looser" than optimum.  In setting up a damping system, I would =
eyeball the=20
action by displacing--say one cm, and watch the return to overshoot two =
mm, and=20
settle to equilibrium again--or a 5 to 1 ratio was in the =
ballpark.  The=20
standard check one can make is the "walk-up" test.  Walk up to the =
base=20
perpendicular to the boom, stand for 20 seconds or so, and then back =
away----If=20
all is well, there will be two traces--alike, but in opposite=20
directions.
    As you walk up, the sensor =
moves=20
slightly to a new equilibrium position.  The damping ratio or =
situation=20
will show nicely---bearing in mind this is a velosity readout rather =
than a=20
displacement--but close enough approximation to give us the damping =
condition=20
quick & easy!!!
     I usually went for a =
8 to 1=20
ratio.  I know with no damping, the boom swings forever from the =
energy of=20
microseisms.  With critical damping, one kills most or all of the=20
action,  The objective of damping is to remove the natural period =
or swing=20
of the pendulum--but not kill it---and there is some =
leeway--------
         &nb=
sp;           &nbs=
p;            =
;            =
             =

Good=20
damping---          &nb=
sp;    =20
Jim Lehman