PSN-L Email List Message
Subject: Re: My first Sensor
From: "tchannel" tchannel@..............
Date: Wed, 20 Sep 2006 22:31:06 -0600
Hi John, Thanks for the reply.
Presently it is not dampen at all. I know the importance of this and will
get that going directly, but when I blow on the beam it seems to return to
full stop in maybe 10 to 15 seconds by the clock, producing a nice image,
that does not go on for ever. I was hoping to prove the amp and filter were
working then address the damp. I also am not 100% sure of my natural
frequency of the horz pendulum, I will re adjust it to as close to 5,10 to
20 seconds perhaps tomorrow. When I first set it up I did not know how to
figure it, but I now think I understand the math. I have all the
dimensions, I just need to move it to the bench for a redo.
As to the amp gain, I think it is 100 not sure, The set up I have, right
or wrong, puts out a 1.5V for a low to a 7.5 volts for a high, a pot to
adjust, I set it at 2.0v. I am using the DATAQ which is happy with, 0 to
10 Volts Again the filter is a Low pass set at 2.5Hz. Before using the
same amp with no filter, I would pick up cars on the street and stomps on
the floor. Now nothing unless I blow on the beam or touching the sensor.
Doing that I get nice signal. Maybe with the addition of the filter I need
to increase the voltage to the AD converter, from 2v to 5v?????
Any advise on any issues, or things to be aware of would be of great value,,
----- Original Message -----
From: "John Popelish"
Sent: Wednesday, September 20, 2006 8:41 PM
Subject: Re: My first Sensor
> tchannel wrote:
>> 1 I could use some advise, if the amp and filter seem to be okay or if I
>> have over done something.
> Two open questions are the damping factor for the pendulum (how many
> cycles do you see after you blow on it, before it settles?) and does your
> amplifier provide enough gain?
>> 2 Another issue is, I am overwhelmed with confusion about "Seconds vs
> > I understand how to work with them and what they mean.
> > But the more I read the more confused I get.
> > The events come in low frequencies,
> > 10 to 20seconds is that 0.1Hz. and .05Hz?
> Hertz means cycles per second. Seconds can refer to the period of one
> cycle (as you use it, above), but it can also refer to time constant of a
> filter. Then it refers to seconds per radian. There are 2*pi radians in
> a cycle.
>> Does that make everything above those Hz, or should I say, below those
>> periods unwanted?
> > You can see I need help.
>> 3 Using AmaSies, what values do I set the Low pass filter,
> > and what values do I set the high pass filter,
> > for enhancing an enlarged detail trace?
> > Do I use both a low and high together.........
> > Some examples would be helpful.
>> The little I have use them has just been trial and error, to get the best
> Someone with more experience in seismology will have to help with these.
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