On Wed, 13 Mar 2013 12:04:34 -0700, Joerg <invalid@invalid.invalid> wrote:>John Larkin wrote: >> On Wed, 13 Mar 2013 11:10:30 -0700, Rob Gaddi >> <rgaddi@technologyhighland.invalid> wrote: >> >>> On Wed, 13 Mar 2013 10:54:17 -0700 >>> Joerg <invalid@invalid.invalid> wrote: >>> >>>> Tim Wescott wrote: >>>>> This is slightly OT for all the groups I'm posting to, but something many >>>>> of you should have done. >>>>> >>>>> I have a need to sample one channel of data at between 200 and 2000 >>>>> samples per second, 12 bits or so, and store it away. >>>>> >>>>> The signal happens to be on a 4-40mA line already, to make life easy for >>>>> getting off-the-shelf hardware. >>>>> >>>>> I need to store hours of guaranteed-uninterrupted data, or failing that, >>>>> store data that's timestamped at the measuring device (not just in the PC >>>>> software) so that I can see what's missing and deal with it. (dropouts >>>>> of even a half second or so would be OK, as long as the timestamps are >>>>> correct). >>>>> >>>>> The mental model I'm carrying around is a laptop PC, connected to some >>>>> little box via USB, quietly buzzing away in a corner making multi- >>>>> megabyte files with the information I want. >>>>> >>>>> I assume that this is a no-brainer with National Instruments hardware and >>>>> software -- am I correct? If not, is there a solution that you can >>>>> recommend? Do you have a favorite other than NI? >>>>> >>>> I usually use this for such jobs: >>>> >>>> http://labjack.com/u3 >>>> >>>> Plus a few resistors. It also comes in a version for LAN connection in >>>> case that's more practical. >>>> >>>> It comes with a light version of Azeotech SCADA software which is really >>>> handy if you don't want to mess with computer programming or Excel-VBA >>>> too much. If you get stuck both Labjack and Azeotech have rather >>>> responsive forums where their respective support staff chimes in. And if >>>> someone screws up a PID you can become the expert and help them out :-) >>>> >>>> -- >>>> Regards, Joerg >>>> >>>> http://www.analogconsultants.com/ >>> Wow. I was actually just wondering about something like this the other day. And the fact that it comes complete with cross-platform drivers and Python bindings makes it pretty seriously nifty. >> >> It should just enumerate as an FTDI serial port, so there would be no >> need for drivers and DLLs. >> > >Not quite. It has a whole slew of settings that are handled by the >driver, AFAIK. It even has a simple set panel where you could goose a >DAC, set a port or read an ADC value (they all show up in the window). >Then there's things like streaming mode and so on. It also needs to know >whether it has foreign device connected to it and whether they should be >addressed with RS232, "Her Majesty" or SPI.These use the FTDI chip, which is the most common and most reliable USB-serial interface: http://www.ftdichip.com/Support/Documents/DataSheets/DLP/dlp-io20-ds-v10.pdf http://www.mouser.com/ds/2/117/DLP-IO14-188487.pdf http://www.ftdichip.com/Support/Documents/DataSheets/DLP/dlp-io8-ds-v15.pdf These generally have a control panel app, and maybe a data logger. But they are also easy to access from a programming language, as a COM port. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
PC Data Acquisition
Started by ●March 13, 2013
Reply by ●March 13, 20132013-03-13
Reply by ●March 13, 20132013-03-13
John Larkin wrote:> On Wed, 13 Mar 2013 12:04:34 -0700, Joerg <invalid@invalid.invalid> > wrote: > >> John Larkin wrote: >>> On Wed, 13 Mar 2013 11:10:30 -0700, Rob Gaddi >>> <rgaddi@technologyhighland.invalid> wrote: >>> >>>> On Wed, 13 Mar 2013 10:54:17 -0700 >>>> Joerg <invalid@invalid.invalid> wrote: >>>> >>>>> Tim Wescott wrote: >>>>>> This is slightly OT for all the groups I'm posting to, but something many >>>>>> of you should have done. >>>>>> >>>>>> I have a need to sample one channel of data at between 200 and 2000 >>>>>> samples per second, 12 bits or so, and store it away. >>>>>> >>>>>> The signal happens to be on a 4-40mA line already, to make life easy for >>>>>> getting off-the-shelf hardware. >>>>>> >>>>>> I need to store hours of guaranteed-uninterrupted data, or failing that, >>>>>> store data that's timestamped at the measuring device (not just in the PC >>>>>> software) so that I can see what's missing and deal with it. (dropouts >>>>>> of even a half second or so would be OK, as long as the timestamps are >>>>>> correct). >>>>>> >>>>>> The mental model I'm carrying around is a laptop PC, connected to some >>>>>> little box via USB, quietly buzzing away in a corner making multi- >>>>>> megabyte files with the information I want. >>>>>> >>>>>> I assume that this is a no-brainer with National Instruments hardware and >>>>>> software -- am I correct? If not, is there a solution that you can >>>>>> recommend? Do you have a favorite other than NI? >>>>>> >>>>> I usually use this for such jobs: >>>>> >>>>> http://labjack.com/u3 >>>>> >>>>> Plus a few resistors. It also comes in a version for LAN connection in >>>>> case that's more practical. >>>>> >>>>> It comes with a light version of Azeotech SCADA software which is really >>>>> handy if you don't want to mess with computer programming or Excel-VBA >>>>> too much. If you get stuck both Labjack and Azeotech have rather >>>>> responsive forums where their respective support staff chimes in. And if >>>>> someone screws up a PID you can become the expert and help them out :-) >>>>> >>>>> -- >>>>> Regards, Joerg >>>>> >>>>> http://www.analogconsultants.com/ >>>> Wow. I was actually just wondering about something like this the other day. And the fact that it comes complete with cross-platform drivers and Python bindings makes it pretty seriously nifty. >>> It should just enumerate as an FTDI serial port, so there would be no >>> need for drivers and DLLs. >>> >> Not quite. It has a whole slew of settings that are handled by the >> driver, AFAIK. It even has a simple set panel where you could goose a >> DAC, set a port or read an ADC value (they all show up in the window). >> Then there's things like streaming mode and so on. It also needs to know >> whether it has foreign device connected to it and whether they should be >> addressed with RS232, "Her Majesty" or SPI. > > These use the FTDI chip, which is the most common and most reliable > USB-serial interface: > > http://www.ftdichip.com/Support/Documents/DataSheets/DLP/dlp-io20-ds-v10.pdf > > http://www.mouser.com/ds/2/117/DLP-IO14-188487.pdf > > http://www.ftdichip.com/Support/Documents/DataSheets/DLP/dlp-io8-ds-v15.pdf > > > These generally have a control panel app, and maybe a data logger. But > they are also easy to access from a programming language, as a COM > port. >I have used a larger FTDI chip with analog plus digital I/O in a design quite a while ago. However, the Labjack is a very different class of device. It's not just a simple I/O pod, there is a uC on there with firmware and all. It can run some simple local stuff such as timers and timed acquisition. You can't do that with just an FTDI driver. Sometimes there are applications where a brief hiccup in the PC or USB link could cause a *KAPOOF* situation, where you need some local smarts on the control pod. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●March 13, 20132013-03-13
Tim Wescott wrote:> This is slightly OT for all the groups I'm posting to, but something many > of you should have done. > > I have a need to sample one channel of data at between 200 and 2000 > samples per second, 12 bits or so, and store it away. > > The signal happens to be on a 4-40mA line already, to make life easy for > getting off-the-shelf hardware. > > I need to store hours of guaranteed-uninterrupted data, or failing that, > store data that's timestamped at the measuring device (not just in the PC > software) so that I can see what's missing and deal with it. (dropouts > of even a half second or so would be OK, as long as the timestamps are > correct). > > The mental model I'm carrying around is a laptop PC, connected to some > little box via USB, quietly buzzing away in a corner making multi- > megabyte files with the information I want. > > I assume that this is a no-brainer with National Instruments hardware and > software -- am I correct? If not, is there a solution that you can > recommend? Do you have a favorite other than NI? > > TIA. >Got a parallel port? Should be LPC... Intel sez it's up to 2Megabytes/s. Not sure if true.. Snippets: https://github.com/klammerj/DOSpar
Reply by ●March 13, 20132013-03-13
On Wed, 13 Mar 2013 11:10:30 -0700, Rob Gaddi <rgaddi@technologyhighland.invalid> wrote:>On Wed, 13 Mar 2013 10:54:17 -0700 >Joerg <invalid@invalid.invalid> wrote: > >> Tim Wescott wrote: >> > This is slightly OT for all the groups I'm posting to, but something many >> > of you should have done. >> > >> > I have a need to sample one channel of data at between 200 and 2000 >> > samples per second, 12 bits or so, and store it away. >> > >> > The signal happens to be on a 4-40mA line already, to make life easy for >> > getting off-the-shelf hardware. >> > >> > I need to store hours of guaranteed-uninterrupted data, or failing that, >> > store data that's timestamped at the measuring device (not just in the PC >> > software) so that I can see what's missing and deal with it. (dropouts >> > of even a half second or so would be OK, as long as the timestamps are >> > correct). >> > >> > The mental model I'm carrying around is a laptop PC, connected to some >> > little box via USB, quietly buzzing away in a corner making multi- >> > megabyte files with the information I want. >> > >> > I assume that this is a no-brainer with National Instruments hardware and >> > software -- am I correct? If not, is there a solution that you can >> > recommend? Do you have a favorite other than NI? >> > >> >> I usually use this for such jobs: >> >> http://labjack.com/u3 >> >> Plus a few resistors. It also comes in a version for LAN connection in >> case that's more practical. >> >> It comes with a light version of Azeotech SCADA software which is really >> handy if you don't want to mess with computer programming or Excel-VBA >> too much. If you get stuck both Labjack and Azeotech have rather >> responsive forums where their respective support staff chimes in. And if >> someone screws up a PID you can become the expert and help them out :-) >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ > >Wow. I was actually just wondering about something like this the other day. And the fact that it comes complete with cross-platform drivers and Python bindings makes it pretty seriously nifty.Maybe 1% of the cost of a NI solution.
Reply by ●March 13, 20132013-03-13
Spehro Pefhany wrote:> On Wed, 13 Mar 2013 11:10:30 -0700, Rob Gaddi > <rgaddi@technologyhighland.invalid> wrote: > >> On Wed, 13 Mar 2013 10:54:17 -0700 >> Joerg <invalid@invalid.invalid> wrote: >> >>> Tim Wescott wrote: >>>> This is slightly OT for all the groups I'm posting to, but something many >>>> of you should have done. >>>> >>>> I have a need to sample one channel of data at between 200 and 2000 >>>> samples per second, 12 bits or so, and store it away. >>>> >>>> The signal happens to be on a 4-40mA line already, to make life easy for >>>> getting off-the-shelf hardware. >>>> >>>> I need to store hours of guaranteed-uninterrupted data, or failing that, >>>> store data that's timestamped at the measuring device (not just in the PC >>>> software) so that I can see what's missing and deal with it. (dropouts >>>> of even a half second or so would be OK, as long as the timestamps are >>>> correct). >>>> >>>> The mental model I'm carrying around is a laptop PC, connected to some >>>> little box via USB, quietly buzzing away in a corner making multi- >>>> megabyte files with the information I want. >>>> >>>> I assume that this is a no-brainer with National Instruments hardware and >>>> software -- am I correct? If not, is there a solution that you can >>>> recommend? Do you have a favorite other than NI? >>>> >>> I usually use this for such jobs: >>> >>> http://labjack.com/u3 >>> >>> Plus a few resistors. It also comes in a version for LAN connection in >>> case that's more practical. >>> >>> It comes with a light version of Azeotech SCADA software which is really >>> handy if you don't want to mess with computer programming or Excel-VBA >>> too much. If you get stuck both Labjack and Azeotech have rather >>> responsive forums where their respective support staff chimes in. And if >>> someone screws up a PID you can become the expert and help them out :-) >>> >>> -- >>> Regards, Joerg >>> >>> http://www.analogconsultants.com/ >> Wow. I was actually just wondering about something like this the other day. And the fact that it comes complete with cross-platform drivers and Python bindings makes it pretty seriously nifty. > > Maybe 1% of the cost of a NI solution. >And no membership fees for continued support. My own Labjack is many years old. Got stuck somewhere recently, asked, received a response within the hour, problem fixed. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●March 13, 20132013-03-13
On Wed, 13 Mar 2013 11:44:58 -0500, Tim Wescott <tim@seemywebsite.com> wrote:>This is slightly OT for all the groups I'm posting to, but something many >of you should have done. > >I have a need to sample one channel of data at between 200 and 2000 >samples per second, 12 bits or so, and store it away.Does it harm if 50/60 Hz mains hum is inserted into the ADC input ? Missing samples could be detected by discontinuous in the 50/60 Hz tone.>The signal happens to be on a 4-40mA line already, to make life easy for >getting off-the-shelf hardware.Are you sure about 4-40 mA ? Standard industrial devices are 4-20 mA ?>I need to store hours of guaranteed-uninterrupted data, or failing that, >store data that's timestamped at the measuring device (not just in the PC >software) so that I can see what's missing and deal with it. (dropouts >of even a half second or so would be OK, as long as the timestamps are >correct). > >The mental model I'm carrying around is a laptop PC, connected to some >little box via USB, quietly buzzing away in a corner making multi- >megabyte files with the information I want.Use the current loop to modulate some voltage/frequency converter and use standard sound card to detect the signal. An audio transformer will take care of any ground loop (hum) problems.
Reply by ●March 13, 20132013-03-13
On Mar 13, 6:19�pm, Tim Wescott <t...@seemywebsite.com> wrote:> On Wed, 13 Mar 2013 12:05:05 -0500, Vladimir Vassilevsky wrote: > > On 3/13/2013 11:44 AM, Tim Wescott wrote: > > >> I have a need to sample one channel of data at between 200 and 2000 > >> samples per second, 12 bits or so, and store it away. > > > For one time deal: take your favorite micro eval board from the shelf; > > connect it to USB to RS232 dongle; put together simple application; > > record file from terminal program on PC. All preparation should take > > less then half an hour. > > It's for a customer over 1000 miles away whose hand I cannot easily hold. > > And it needs to deal with 4-40mA, for which I have no hardware. > > But it's a tempting idea. >you really mean 4-40mA not the usual 4-20mA ? anyway it is just a resistor if you can live with 10 bits, something like this won't even need a pc https://www.sparkfun.com/products/10216 -Lasse
Reply by ●March 13, 20132013-03-13
On Wed, 13 Mar 2013 22:29:41 +0200, upsidedown wrote:> On Wed, 13 Mar 2013 11:44:58 -0500, Tim Wescott <tim@seemywebsite.com> > wrote: > >>This is slightly OT for all the groups I'm posting to, but something >>many of you should have done. >> >>I have a need to sample one channel of data at between 200 and 2000 >>samples per second, 12 bits or so, and store it away.<snip>> Are you sure about 4-40 mA ? Standard industrial devices are 4-20 mA ?<snip> Oops... -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Reply by ●March 13, 20132013-03-13
langwadt@fonz.dk wrote:> On Mar 13, 6:19 pm, Tim Wescott <t...@seemywebsite.com> wrote: >> On Wed, 13 Mar 2013 12:05:05 -0500, Vladimir Vassilevsky wrote: >>> On 3/13/2013 11:44 AM, Tim Wescott wrote: >>>> I have a need to sample one channel of data at between 200 and 2000 >>>> samples per second, 12 bits or so, and store it away. >>> For one time deal: take your favorite micro eval board from the shelf; >>> connect it to USB to RS232 dongle; put together simple application; >>> record file from terminal program on PC. All preparation should take >>> less then half an hour. >> It's for a customer over 1000 miles away whose hand I cannot easily hold. >> >> And it needs to deal with 4-40mA, for which I have no hardware. >> >> But it's a tempting idea. >> > > you really mean 4-40mA not the usual 4-20mA ? >In America everything is a little bigger :-)> anyway it is just a resistor > > > if you can live with 10 bits, something like this won't even need a > pc > > https://www.sparkfun.com/products/10216 >These are cool, but not enough memory for Tim's job: http://www.lascarelectronics.com/temperaturedatalogger.php?datalogger=103 -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●March 13, 20132013-03-13
On Mar 13, 9:54�pm, Joerg <inva...@invalid.invalid> wrote:> langw...@fonz.dk wrote: > > On Mar 13, 6:19 pm, Tim Wescott <t...@seemywebsite.com> wrote: > >> On Wed, 13 Mar 2013 12:05:05 -0500, Vladimir Vassilevsky wrote: > >>> On 3/13/2013 11:44 AM, Tim Wescott wrote: > >>>> I have a need to sample one channel of data at between 200 and 2000 > >>>> samples per second, 12 bits or so, and store it away. > >>> For one time deal: take your favorite micro eval board from the shelf; > >>> connect it to USB to RS232 dongle; put together simple application; > >>> record file from terminal program on PC. All preparation should take > >>> less then half an hour. > >> It's for a customer over 1000 miles away whose hand I cannot easily hold. > > >> And it needs to deal with 4-40mA, for which I have no hardware. > > >> But it's a tempting idea. > > > you really mean 4-40mA not the usual 4-20mA ? > > In America everything is a little bigger :-);)> > > anyway it is just a resistor > > > if you can live with 10 bits, something like this won't even need a > > pc > > >https://www.sparkfun.com/products/10216 > > These are cool, but not enough memory for Tim's job: > > http://www.lascarelectronics.com/temperaturedatalogger.php?datalogger... >yeh and much too slow, maximum is 1Hz, he wants +200Hz -Lasse
