PC Printer Port Controls Data Logger

A

Animesh Maurya

Guest
Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142

Please see the above link, a PC printer port data logger system, built
around with MAX132 (ą18-Bit ADC with Serial Interface).

I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.

I don't know whether it is a software limitation or a hardware one,
which freezes it to 1data/sec.

But if this is hardware one, how can I increase the data capturing
rate up to 1data/msecs.

Finally if all above said cannot be done, someone please suggest a
appropriate link to have some other data logger.

Any help is strongly appreciated.

Thank you

Best regards,
Animesh Maurya
 
On 26 Apr 2004 23:17:58 -0700, animesh_m@eudoramail.com (Animesh Maurya) wrote:

Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142

Please see the above link, a PC printer port data logger system, built
around with MAX132 (ą18-Bit ADC with Serial Interface).

I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.

I don't know whether it is a software limitation or a hardware one,
which freezes it to 1data/sec.

But if this is hardware one, how can I increase the data capturing
rate up to 1data/msecs.

Finally if all above said cannot be done, someone please suggest a
appropriate link to have some other data logger.
Click to expand...
If you don't really need an 18-bit ADC but can surviuve with 12-bit (that's 0 to
4095 unipolar) and eight channels, with four binary outputs, have a look at

http://www.kitsrus.com/kits.html#k118
 
On 26 Apr 2004 23:17:58 -0700, animesh_m@eudoramail.com (Animesh
Maurya) wrote:

Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142

Please see the above link, a PC printer port data logger system, built
around with MAX132 (ą18-Bit ADC with Serial Interface).

I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.

I don't know whether it is a software limitation or a hardware one,
which freezes it to 1data/sec.

But if this is hardware one, how can I increase the data capturing
rate up to 1data/msecs.

Finally if all above said cannot be done, someone please suggest a
appropriate link to have some other data logger.

Any help is strongly appreciated.

Thank you

Best regards,
Animesh Maurya
Click to expand...

I have not studied this circuit carefully, but I've
used similar serial ADCs before. The ones I've
used were 12 bit (LTC1285), and the problem
is that you are trying to send serial data over a
parallel port, where your software has to take care
of all the handshaking. For each and every bit
of each data conversion, you have to do a complete
handshake, which means a *lot* of I/O traffic.
In pure assembly language I was able to nurse
the LTC1285 up to about 15 kHz overall sample
rate for a single channel, but that was about the limit.
If you also have to send channel control signals,
as well as trasnfer additional bits, your top speed
will be less. Don't know about the Maxim chip,
but on the LTC it was possible to reduce resolution
by simply not reading the LSBs and get a speed
increase.

All things considered, I'd guess you could expect
at least a few thousand samples per second.
Note that this is not especially dependent upon
CPU speed, since the I/O bus cycles are around
1 usec each and I don't think that faster systems
run the port I/O any faster than that. However,
if you are writing in a high-level language instead
of assembly, then the CPU speed might make a
difference in burning through all the high-level
deadwood.

Also note that this will require DOS in order to get
direct access to the I/O ports, which means you
can't do this in WinNT, 2K, or XP. However, there
are generic I/O drivers available for these that are
supposed to give you access to the ports. I haven't
tried these. One name that comes to mind is GIVEIO.
Check out Jan Axelson's site <www.lvr.com> for more
info on these drivers, as well as all sorts of port info.

Hope this helps!



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
 
On Tue, 27 Apr 2004 13:04:14 GMT, Bob Masta <NoSpam@daqarta.com> wrote:

On 26 Apr 2004 23:17:58 -0700, animesh_m@eudoramail.com (Animesh
Maurya) wrote:

Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142
....

....
handshake, which means a *lot* of I/O traffic
Click to expand...
.....
Also consider the settling time when switching channels (for the port to
settle).
If you are after a single stream things can happen alot faster.
 
Subject: PC Printer Port Controls Data Logger
From: animesh_m@eudoramail.com (Animesh Maurya)
Date: 4/27/2004 1:17 AM Central Standard Time
Message-id: <9f6c9f5d.0404262217.16a57591@posting.google.com

Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142

Please see the above link, a PC printer port data logger system, built
around with MAX132 (ą18-Bit ADC with Serial Interface).

I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.

I don't know whether it is a software limitation or a hardware one,
which freezes it to 1data/sec.

But if this is hardware one, how can I increase the data capturing
rate up to 1data/msecs.

Finally if all above said cannot be done, someone please suggest a
appropriate link to have some other data logger.

Any help is strongly appreciated.

Thank you

Best regards,
Animesh Maurya
Click to expand...
Hi, Animesh. When all else fails, read the data sheet. You can use software
to set conversion rate on the MAX132, but it only goes to 100 Hz. At higher
conversion rates, line frequency noise will kill your readings, anyway.

You're not going to be able to get to a 1KHz sample rate with 18-bit
resolution with an inexpensive printer port blivet for a number of reasons,
including electrical noise introduced by the PC, line frequency noise, and the
tragic necessity of bit-banging the parallel port into submission as a serial
interface (the beatings will continue until morale improves! ;^) ). The
overhead involved in that means you'll only approach 1KHz conversion rates with
a DOS setup written in assembler or C. I'd actually feel 12 or 13 bits will be
about the best you could expect from a non-galvanically isolated A/D interface
to a computer port at 1KHz sample rate.

You're really going to need something with a processor on-board with memory
buffer, so you can let your computer concentrate on doing its job while data
conversions are taking place. If you've got a USB port available, you might
want to try something like the LabJack U12. It has 8 Single-Ended or 4
Differential 12-Bit Analog Inputs, and can stream A/D data at about 1.2KHz.
It's $119.00 USD, it's got a lot of other goodies, and runs with Win98SE, ME,
2000 and XP. Neat toy, and it should give you what you want.

http://www.labjack.com/labjack_u12.html

Good luck
Chris
 
On a sunny day (26 Apr 2004 23:17:58 -0700) it happened
animesh_m@eudoramail.com (Animesh Maurya) wrote in
<9f6c9f5d.0404262217.16a57591@posting.google.com>:

Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142

Please see the above link, a PC printer port data logger system, built
around with MAX132 (ą18-Bit ADC with Serial Interface).

I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.

I don't know whether it is a software limitation or a hardware one,
which freezes it to 1data/sec.

But if this is hardware one, how can I increase the data capturing
rate up to 1data/msecs.

Finally if all above said cannot be done, someone please suggest a
appropriate link to have some other data logger.

Any help is strongly appreciated.

Thank you

Best regards,
Animesh Maurya
When using a par port input you need to consider the task switching
Click to expand...
and interrupt times of the operating system.
We are talking milliseconds here.
It could be done, but you would have to buffer first in hardware after
the AD.
I do not know if that MAX 132 has somne build in buffering.
Any micro controller with some RAM (internal or external) would do.
So, you would have to read say samples from the buffer with the PC
until that buffer is empty, the micro would do the timing.
JP
 
Thanks all for those nifty ideas.

This time I was looking for cooked food, I have to do a lot of reading
work before implementing any for yours above thought.

Thanks for your time

Regards,
Animesh Maurya
 
Hi Animesh,

(ą18-Bit ADC with Serial Interface).
Click to expand...
Nope, 15 bits (or ą14 bits if you will).


I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.
Click to expand...
That depends on what you are doing.
HAve you considered one of the (freeware) oscilloscopes (some with FFT-
analysis as well), which utilizes your sound card for the A/D ?

<URL:http://polly.phys.msu.su/~zeld/osc251.zip> is one.


--
Regards,
Soeren

* If it puzzles you dear... Reverse engineer *
 
On 26 Apr 2004 23:17:58 -0700, animesh_m@eudoramail.com (Animesh
Maurya) wrote:

Hi all,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/142

Please see the above link, a PC printer port data logger system, built
around with MAX132 (ą18-Bit ADC with Serial Interface).

I am very keen to have such a data logger for my project work,
but over there it is written that data acquisition rate is 1data/sec,
which is quite slow to work with.

I don't know whether it is a software limitation or a hardware one,
which freezes it to 1data/sec.

But if this is hardware one, how can I increase the data capturing
rate up to 1data/msecs.

Finally if all above said cannot be done, someone please suggest a
appropriate link to have some other data logger.

Any help is strongly appreciated.

Thank you

Best regards,
Animesh Maurya
Click to expand...

One additional thought: You might want to check out
the Dataq "starter" system. It's under US$30 and
comes with a demo of their Windows software. Plugs into a
serial port and acquires 4 channels at a few hundred
samples per second. Or at least the ones they were giving
away free did, a few years ago. They might be even
faster now. At the time, the only option was to use their
software, but I think there was a lot of user interest in
developing other applications. I'd recommend checking
the Dataq site to find out about the model number and specs,
then Googling for what others might have done with it.

Just a thought....



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top