On Tue, 06 Jan 2004 20:27:08 GMT, "Vic Fraenckel"
wrote:

You might also explore U.S. Digital http://www.usdigital.com/ as they have
an inclinometer that might do the trick. Check out the T6 unit. I have used
their shaft encoder products and am seriously considering the T6.

Hey, nice products. The A2T looks like it might fit the bill for me, and the
serial interface they use means I can hook a few of them into the 1 serial
port!

Only question is the dynamic performance - 250mSec settling time is a bit
slow.

If we have 30° roll with a period of 10 seconds (pretty severe, but it might
happen), then that is 3 degrees per second. I guess that's still better than
1 degree accuracy - just. At that price I might grab a couple of them & have
a play regardless, while waiting for the Hippy price to come back to me!

Thanks for all the help guys - I'll let you know how it works in the real
world as we are doing these tests for a project with DNV, so the results
should be public.

Dave

"Dave Baker" wrote in message
...
On Thu, 18 Sep 2003 15:16:54 +0800, Dave Baker
wrote:

Does anyone know of a pitch & roll sensor suitable for installation on a
vessel? I need to log pitch & roll on a boat

I'll have another go at this, seeing that I didn't get an answer a while
back, and some units that I have found since have turned out to be
unsuitable.

Anyone know of any pitch/roll sensors that are designed specifically for
measuring pitch & roll in vessels? The units that I have found apparently
are
more for static applications, and are affected by acceleration, so are not
accurate in dynamic situations.

I'd settle for any USB or serial output, and if absolutely necessary then
I'd
go for 4-20mA output & shove a converter on the end.

Dave

I have sailed on Dynamic Positioned vessels that used Hippy pitch and roll
sensors from Datawell, they are basically about the size of a dustbin, and
have a pendulum supported inside some fluid, never had one open, but as far
as I remember the output was 4-20mA current loop.

The other type were made by Robertson or Kongsberg , (Now Simrad), they used
the gyropscopic principal to measure pitch and roll, and I think they were
probably adapted from aircraft use, because they used a strange AC power
source 440Hz/48V.

Both units were fairly expensive, contact either Datawell or Simrad for
details

garry crothers

Dave Baker wrote:

Anyone know of any pitch/roll sensors that are designed specifically for
measuring pitch & roll in vessels? The units that I have found apparently are
more for static applications, and are affected by acceleration, so are not
accurate in dynamic situations.

Try this for a start. There are several manufacturers of electrolytic
sensors and I am sure you can get what you need in just about any output
configuration.

http://www.microstrain.com/FAS-E.htm

You might also try and contact BP Oil Shipping, they installed strain
monitoring on their Alaska tankers a few years ago.

Rick

On Wed, 07 Jan 2004 18:32:24 GMT, Rick wrote:

Try this for a start. There are several manufacturers of electrolytic
sensors and I am sure you can get what you need in just about any output
configuration.

http://www.microstrain.com/FAS-E.htm

The FAS-E looks slightly interesting, though they have a FAS-G which looks a
lot better. In fact the PDF manual for the FAS-G has some useful information
which might help in the lively debate going on regarding suitability of
accelerometers for this task! :-)

"What makes FAS-G unique is not only its ability to measure static angles,
but also dynamic, fast angular movements. Through the use of the two
accelerometers and one piezo-ceramic gyro coupled with the requisite digital
filtering and embedded software tracking algorithms, FAS-G provides dynamic
response while maintaining the DC (static) measurement accuracy. As a result,
during rapid angular movements, both static and the dynamic components of
movement can be measured. This is not possible with conventional
inclinometers based on fluidic electrolytes or DC response accelerometers."

Ooh - just spotted the 3DM-G on the same site - seems to be exactly what I
need, for about US$1500. This looks good. 3 weeks lead time is about the only
worry.

Thanks,

Dave

You are on to a possibility. You should know that there is a lot more than
meets the eye in what you are buying. These devices require high
computational capabilities. Hopefully there are canned algorithms available
to provide the outputs that you require. But they have the potential to
provide proper pitch and roll outputs AND simultaneous acceleration outputs
Max Lynn

"Dave Baker" wrote in message
...
On Wed, 07 Jan 2004 18:32:24 GMT, Rick wrote:

Try this for a start. There are several manufacturers of electrolytic
sensors and I am sure you can get what you need in just about any output
configuration.

http://www.microstrain.com/FAS-E.htm

The FAS-E looks slightly interesting, though they have a FAS-G which looks
a
lot better. In fact the PDF manual for the FAS-G has some useful
information
which might help in the lively debate going on regarding suitability of
accelerometers for this task! :-)

"What makes FAS-G unique is not only its ability to measure static angles,
but also dynamic, fast angular movements. Through the use of the two
accelerometers and one piezo-ceramic gyro coupled with the requisite
digital
filtering and embedded software tracking algorithms, FAS-G provides
dynamic
response while maintaining the DC (static) measurement accuracy. As a
result,
during rapid angular movements, both static and the dynamic components of
movement can be measured. This is not possible with conventional
inclinometers based on fluidic electrolytes or DC response
accelerometers."

Ooh - just spotted the 3DM-G on the same site - seems to be exactly what I
need, for about US$1500. This looks good. 3 weeks lead time is about the
only
worry.

Thanks,

Dave

On Wed, 7 Jan 2004 21:02:09 -0800, "maxlynn" wrote:

You are on to a possibility. You should know that there is a lot more than
meets the eye in what you are buying. These devices require high
computational capabilities. Hopefully there are canned algorithms available
to provide the outputs that you require. But they have the potential to
provide proper pitch and roll outputs AND simultaneous acceleration outputs

I'll just log all the data - my boss has the degrees in Maths & Surveying, so
he can be the one that has to make sense of it all! :-)

Dave