Flowmeters and 4-20mA outputs.
I want to convert the 4-20mA signal which represents flow rate from a
natural gas flowmeter and transform it into total flow. This data
then needs to be converted into a serial bit stream which I would
like to access using the SERIN/SEROUT commands from my BS2. I have
thought of using a 12-bit A/D converter, a 250 ohm resistor, and some
intense software programing, but is there a better way to accomplish
this? I don't want to tie up my BS2 by constantly checking the flow
rate because I have it performing a lot of other tasks. Is there a
chip out there or some other device that can do this for me cheaply?
If that doesn't work, another option I have is to use the pulse
output from the meter. Any help would be greatly appreciated.
natural gas flowmeter and transform it into total flow. This data
then needs to be converted into a serial bit stream which I would
like to access using the SERIN/SEROUT commands from my BS2. I have
thought of using a 12-bit A/D converter, a 250 ohm resistor, and some
intense software programing, but is there a better way to accomplish
this? I don't want to tie up my BS2 by constantly checking the flow
rate because I have it performing a lot of other tasks. Is there a
chip out there or some other device that can do this for me cheaply?
If that doesn't work, another option I have is to use the pulse
output from the meter. Any help would be greatly appreciated.
Comments
total flow, then what would the BS2 be accessing? A chip to do what?
If you can get a pulse from the meter, how about using the count
command to count the pulses?
How many I/O are you using on the BS2? The pulses may be used to
drive a discreet counter, which you can quickly read as a parallel
data, though you may need to use several (8+) lines, but 2-8 bit
counters, a little multiplexing, and you could read it in as a high
and low byte. Once read every few seconds or so, you could reset the
counter for a fresh count, accumulating your readings for total.
Or, a slightly more expensive idea, use 2 BS2s, one simply collecting
data, and the other occasionally polling it for the serial totals.
Just some thoughts, reply back if any sound promising and you need
more help.
-Martin Hebel
SelmaWare Solutions
S-Plot:Graphical Data Acquisition and Control
http://www.selmaware.com/s-plot
Southern Illinois University Carbondale
Electronics Systems Technologies (soon to be...)
http://www.siu.edu/~imsasa/elm
--- In basicstamps@y..., prstava@e... wrote:
> I want to convert the 4-20mA signal which represents flow rate from
a
> natural gas flowmeter and transform it into total flow. This data
> then needs to be converted into a serial bit stream which I would
> like to access using the SERIN/SEROUT commands from my BS2. I have
> thought of using a 12-bit A/D converter, a 250 ohm resistor, and
some
> intense software programing, but is there a better way to
accomplish
> this? I don't want to tie up my BS2 by constantly checking the
flow
> rate because I have it performing a lot of other tasks. Is there a
> chip out there or some other device that can do this for me
cheaply?
> If that doesn't work, another option I have is to use the pulse
> output from the meter. Any help would be greatly appreciated.
microphone input? What I'd like to do is to
get a sound wave into the Stamp and do some analysis
of the wave, but I can't digitize it fast enough.
Therefore, what I thought of doing was to grab
the bit stream of already-digitized data from the
sound card, and then I don't have to worry about
digitizing it myself.
By "sound card" I mean a common one found in
any PC. What I'm thinking of is something that
uses basically digitizes sound, and outputs a
bit stream.
Any ideas? Thanx....JP Harrison
detect signal, and every fifteen minutes it SERIN/SEROUTS to five
seperate pieces of equipment to obtain two temperature readings and
three power readings. I don't think I would be able to use the same
BS2 to also constantly monitor a 4-20mA or pulse signal. Maybe your
idea of a counter would work, but we're trying to make this senior
design project compatible with most meters and not all gas flow
meters have a pulse output (a larger percentage have 4-20mA current
loops).
I'll look into the counter idea, it may work if it can count very
high numbers.
Thanks for your help,
Don Paulson
--- In basicstamps@y..., martin@s... wrote:
> A little confudsed here, if you want another chip to be tracking
> total flow, then what would the BS2 be accessing? A chip to do what?
>
> If you can get a pulse from the meter, how about using the count
> command to count the pulses?
>
> How many I/O are you using on the BS2? The pulses may be used to
> drive a discreet counter, which you can quickly read as a parallel
> data, though you may need to use several (8+) lines, but 2-8 bit
> counters, a little multiplexing, and you could read it in as a high
> and low byte. Once read every few seconds or so, you could reset
the
> counter for a fresh count, accumulating your readings for total.
>
> Or, a slightly more expensive idea, use 2 BS2s, one simply
collecting
> data, and the other occasionally polling it for the serial totals.
>
> Just some thoughts, reply back if any sound promising and you need
> more help.
>
> -Martin Hebel
> SelmaWare Solutions
> S-Plot:Graphical Data Acquisition and Control
> http://www.selmaware.com/s-plot
>
> Southern Illinois University Carbondale
> Electronics Systems Technologies (soon to be...)
> http://www.siu.edu/~imsasa/elm
>
> --- In basicstamps@y..., prstava@e... wrote:
> > I want to convert the 4-20mA signal which represents flow rate
from
> a
> > natural gas flowmeter and transform it into total flow. This
data
> > then needs to be converted into a serial bit stream which I would
> > like to access using the SERIN/SEROUT commands from my BS2. I
have
> > thought of using a 12-bit A/D converter, a 250 ohm resistor, and
> some
> > intense software programing, but is there a better way to
> accomplish
> > this? I don't want to tie up my BS2 by constantly checking the
> flow
> > rate because I have it performing a lot of other tasks. Is there
a
> > chip out there or some other device that can do this for me
> cheaply?
> > If that doesn't work, another option I have is to use the pulse
> > output from the meter. Any help would be greatly appreciated.