Nico Coesel wrote:> Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: > > >>RogerN wrote: >> >> >>>"Jamie" wrote in message news:Uat4r.24370$kv1.5096@newsfe03.iad... >>> >>><snip> >>> >>>>Save yourself some time and look at the "Click PLC" systems. >>>>AutomationDirect has them. >>>> >>>> You can get a CPU with Analog in that has 3 serial ports, put a user >>>>screen on it power supply and add on IO modules for less than what you'll >>>>end up paying peace mealing it together. >>>> >>>> The programming software is free and the cable is cheap. You could >>>>most likely make your own cable that would work fine. >>>> >>>> The analog has 2 ADC inputs if I remember and 2 DAC outputs. both >>> >>>I agree with you on the PLC solution but I'm wanting to use an Arduino for >>>the portability, I failed to mention that in the first post. >>> >>>RogerN >>> >>> >> >>The Clicks can use their cheap C-mon screen that has keys. >> >> Just something to remember. > > > The clicks look nice but I see no A/D D/A blocks. Or am I looking > wrong? >The analog is via selection of the CPU.. scroll down to their highest priced unit and then select your logic types. They give you 2 in and 2 out, with 4 logic in/out on top of that. That is just the CPU, you can add various I/0 modules however. They don't have a add on module for analog, at least not yet. Jamie
Load Cell to Arduino
Started by ●March 3, 2012
Reply by ●March 3, 20122012-03-03
Reply by ●March 3, 20122012-03-03
Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:>Nico Coesel wrote: > >> Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: >> >> >>>RogerN wrote: >>> >>> >>>>"Jamie" wrote in message news:Uat4r.24370$kv1.5096@newsfe03.iad... >>>> >>>><snip> >>>> >>>>>Save yourself some time and look at the "Click PLC" systems. >>>>>AutomationDirect has them. >>>>> >>>>> You can get a CPU with Analog in that has 3 serial ports, put a user >>>>>screen on it power supply and add on IO modules for less than what you'll >>>>>end up paying peace mealing it together. >>>>> >>>>> The programming software is free and the cable is cheap. You could >>>>>most likely make your own cable that would work fine. >>>>> >>>>> The analog has 2 ADC inputs if I remember and 2 DAC outputs. both >>>> >>>>I agree with you on the PLC solution but I'm wanting to use an Arduino for >>>>the portability, I failed to mention that in the first post. >>>> >>>>RogerN >>>> >>>> >>> >>>The Clicks can use their cheap C-mon screen that has keys. >>> >>> Just something to remember. >> >> >> The clicks look nice but I see no A/D D/A blocks. Or am I looking >> wrong? >> > >The analog is via selection of the CPU.. > >scroll down to their highest priced unit and then >select your logic types. > > They give you 2 in and 2 out, with 4 logic in/out on top >of that. That is just the CPU, you can add various I/0 modules >however. > >They don't have a add on module for analog, at least not yet.Its 5V only. Pity. I've found these but shipping prices to NL are insane: http://www.bb-elec.com/product_multi_family.asp?MultiFamilyId=39&Trail=158&TrailType=Main -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
Reply by ●March 3, 20122012-03-03
"Martin Riddle" <martin_rid@verizon.net> wrote:> >"RogerN" <regor@midwest.net> wrote in message >news:XpadnaQ-Q5YXAc_SnZ2dnUVZ_s6dnZ2d@earthlink.com... >> >> "Tim Wescott" wrote in message >> news:qLmdnfK-LczQ68_SnZ2dnUVZ_hydnZ2d@web-ster.com... >> >>>On Sat, 03 Mar 2012 11:33:42 -0600, RogerN wrote: >>>> >>>><snip> >>> >>>Try doing some directed looking for applications notes showing how to >>>use >>>an ADC with a load cell. Hooking up the ADC to the Arduino is a >>>separate >>>problem which (hopefully) will be much more routine for you. >>> >>>-- >>>Tim Wescott >>>Control system and signal processing consulting >>>www.wescottdesign.com >>> >> >> Most of what I have seen is to run the load cell through an >> instrumentation amp then to the A/D. I have used the Arduino with a >> serial 12 bit A/D before, LTC1298 if I remember correctly. I'm >> wanting as high of resolution as practical, having found oversized >> > >Oversample a 16-bit ADC, acquisition time will be slow. But you can get >18 or 20 bits resolution if speed is not an issue.I doubt that. You can't get more bits out of an ADC. Its better to get rid of the noise in the analog domain and be able to use the full resolution. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
Reply by ●March 3, 20122012-03-03
On Sat, 03 Mar 2012 23:37:43 GMT, nico@puntnl.niks (Nico Coesel) wrote:>"Martin Riddle" <martin_rid@verizon.net> wrote: > >> >>"RogerN" <regor@midwest.net> wrote in message >>news:XpadnaQ-Q5YXAc_SnZ2dnUVZ_s6dnZ2d@earthlink.com... >>> >>> "Tim Wescott" wrote in message >>> news:qLmdnfK-LczQ68_SnZ2dnUVZ_hydnZ2d@web-ster.com... >>> >>>>On Sat, 03 Mar 2012 11:33:42 -0600, RogerN wrote: >>>>> >>>>><snip> >>>> >>>>Try doing some directed looking for applications notes showing how to >>>>use >>>>an ADC with a load cell. Hooking up the ADC to the Arduino is a >>>>separate >>>>problem which (hopefully) will be much more routine for you. >>>> >>>>-- >>>>Tim Wescott >>>>Control system and signal processing consulting >>>>www.wescottdesign.com >>>> >>> >>> Most of what I have seen is to run the load cell through an >>> instrumentation amp then to the A/D. I have used the Arduino with a >>> serial 12 bit A/D before, LTC1298 if I remember correctly. I'm >>> wanting as high of resolution as practical, having found oversized >>> >> >>Oversample a 16-bit ADC, acquisition time will be slow. But you can get >>18 or 20 bits resolution if speed is not an issue. > >I doubt that. You can't get more bits out of an ADC. Its better to get >rid of the noise in the analog domain and be able to use the full >resolution.Sure you can. Averaging will give more bits than there is hardware for. I played that game with Tektronix digitizers 35 years ago, to pull signals out of the digitization noise. The number of bits gained (assuming uncorrelated noise) is proportional to the log of the number of samples, so it gets boring fast, though. ;-)
Reply by ●March 3, 20122012-03-03
"krw@att.bizzzzzzzzzzzz" <krw@att.bizzzzzzzzzzzz> wrote:>On Sat, 03 Mar 2012 23:37:43 GMT, nico@puntnl.niks (Nico Coesel) wrote: > >>"Martin Riddle" <martin_rid@verizon.net> wrote: >> >>> >>>"RogerN" <regor@midwest.net> wrote in message >>>news:XpadnaQ-Q5YXAc_SnZ2dnUVZ_s6dnZ2d@earthlink.com... >>>> >>>> "Tim Wescott" wrote in message >>>> news:qLmdnfK-LczQ68_SnZ2dnUVZ_hydnZ2d@web-ster.com... >>>> >>>>>On Sat, 03 Mar 2012 11:33:42 -0600, RogerN wrote: >>>>>> >>>>>><snip> >>>>> >>>>>Try doing some directed looking for applications notes showing how to >>>>>use >>>>>an ADC with a load cell. Hooking up the ADC to the Arduino is a >>>>>separate >>>>>problem which (hopefully) will be much more routine for you. >>>>> >>>>>-- >>>>>Tim Wescott >>>>>Control system and signal processing consulting >>>>>www.wescottdesign.com >>>>> >>>> >>>> Most of what I have seen is to run the load cell through an >>>> instrumentation amp then to the A/D. I have used the Arduino with a >>>> serial 12 bit A/D before, LTC1298 if I remember correctly. I'm >>>> wanting as high of resolution as practical, having found oversized >>>> >>> >>>Oversample a 16-bit ADC, acquisition time will be slow. But you can get >>>18 or 20 bits resolution if speed is not an issue. >> >>I doubt that. You can't get more bits out of an ADC. Its better to get >>rid of the noise in the analog domain and be able to use the full >>resolution. > >Sure you can. Averaging will give more bits than there is hardware for. I >played that game with Tektronix digitizers 35 years ago, to pull signals out >of the digitization noise. The number of bits gained (assuming uncorrelated >noise) is proportional to the log of the number of samples, so it gets boring >fast, though. ;-)That only works if there is enough noise to flip at least the LSB bit. If the signal sits somewhere between 2 codes you can oversample all you want but you'll never get any extra bits of resolution. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
Reply by ●March 3, 20122012-03-03
Nico Coesel wrote:> Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: > > >>Nico Coesel wrote: >> >> >>>Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: >>> >>> >>> >>>>RogerN wrote: >>>> >>>> >>>> >>>>>"Jamie" wrote in message news:Uat4r.24370$kv1.5096@newsfe03.iad... >>>>> >>>>><snip> >>>>> >>>>>>Save yourself some time and look at the "Click PLC" systems. >>>>>>AutomationDirect has them. >>>>>> >>>>>>You can get a CPU with Analog in that has 3 serial ports, put a user >>>>>>screen on it power supply and add on IO modules for less than what you'll >>>>>>end up paying peace mealing it together. >>>>>> >>>>>>The programming software is free and the cable is cheap. You could >>>>>>most likely make your own cable that would work fine. >>>>>> >>>>>>The analog has 2 ADC inputs if I remember and 2 DAC outputs. both >>>>> >>>>>I agree with you on the PLC solution but I'm wanting to use an Arduino for >>>>>the portability, I failed to mention that in the first post. >>>>> >>>>>RogerN >>>>> >>>>> >>>> >>>>The Clicks can use their cheap C-mon screen that has keys. >>>> >>>>Just something to remember. >>> >>> >>>The clicks look nice but I see no A/D D/A blocks. Or am I looking >>>wrong? >>> >> >>The analog is via selection of the CPU.. >> >>scroll down to their highest priced unit and then >>select your logic types. >> >> They give you 2 in and 2 out, with 4 logic in/out on top >>of that. That is just the CPU, you can add various I/0 modules >>however. >> >>They don't have a add on module for analog, at least not yet. > > > Its 5V only. Pity. > I've found these but shipping prices to NL are insane: > > http://www.bb-elec.com/product_multi_family.asp?MultiFamilyId=39&Trail=158&TrailType=Main >Hmm, no DAC outputs though? Jamie
Reply by ●March 3, 20122012-03-03
Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:>Nico Coesel wrote: > >> Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: >> >> >>>Nico Coesel wrote: >>> >>> >>>>Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: >>>> >>>> >>>> >>>>>RogerN wrote: >>>>> >>>>> >>>>> >>>>>>"Jamie" wrote in message news:Uat4r.24370$kv1.5096@newsfe03.iad... >>>>>> >>>>>><snip> >>>>>> >>>>>>>Save yourself some time and look at the "Click PLC" systems. >>>>>>>AutomationDirect has them. >>>>>>> >>>>>>>You can get a CPU with Analog in that has 3 serial ports, put a user >>>>>>>screen on it power supply and add on IO modules for less than what you'll >>>>>>>end up paying peace mealing it together. >>>>>>> >>>>>>>The programming software is free and the cable is cheap. You could >>>>>>>most likely make your own cable that would work fine. >>>>>>> >>>>>>>The analog has 2 ADC inputs if I remember and 2 DAC outputs. both >>>>>> >>>>>>I agree with you on the PLC solution but I'm wanting to use an Arduino for >>>>>>the portability, I failed to mention that in the first post. >>>>>> >>>>>>RogerN >>>>>> >>>>> >>>>>The Clicks can use their cheap C-mon screen that has keys. >>>>> >>>>>Just something to remember. >>>> >>>> >>>>The clicks look nice but I see no A/D D/A blocks. Or am I looking >>>>wrong? >>>> >>> >>>The analog is via selection of the CPU.. >>> >>>scroll down to their highest priced unit and then >>>select your logic types. >>> >>> They give you 2 in and 2 out, with 4 logic in/out on top >>>of that. That is just the CPU, you can add various I/0 modules >>>however. >>> >>>They don't have a add on module for analog, at least not yet. >> >> >> Its 5V only. Pity. >> I've found these but shipping prices to NL are insane: >> >> http://www.bb-elec.com/product_multi_family.asp?MultiFamilyId=39&Trail=158&TrailType=Main >> >Hmm, no DAC outputs though?You have to scroll al the way down for that: SG2-2AO I've found a similar system which has a distributor in NL: http://www.xlogic-plc.com/product.php?class=34&classIndex=product -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
Reply by ●March 3, 20122012-03-03
On Mar 3, 11:33=A0am, "RogerN" <re...@midwest.net> wrote:> I'm interested in making a load cell scale using an Arduino so I can prog=ram> special features that currently available scales don't have. > > Any thoughts on best way to get high resolution data to an Arduino > microcontroller board? > > AD7730 chip, or Instrumentation amp to A/D converter? > > Anything readily available such as load cell in and serial data out? > > Most of the ready made load cell indicators I've been looking at have eit=her> 20 bit or 24 bit A/D but only give 10,000 or so steps of resolution, I gu=ess> because of noise? > > The features I want to be able to program in are things like reverse tari=ng,> where you weigh a full container, select reverse tare, then empty the > container, and scale calculates tells how much product was removed, I thi=nk> this is also called loss of weight weighing or something like that. > > Another feature is I want to be able to calibrate with homemade calibrati=on> weights. =A0The idea is that I will come up with a weight heavy enough to > calibrate in the range I want, then take it to work and have it weighed o=n> an accurate calibrated scale, stamp the actual weight on it and it's good > enough for my purposes. =A0So far I haven't seen a scale that will let yo=u> calibrate with something like a 100.123 pound weight, for software it isn='t> a problem. > > The best feature I want is to be able to add is using one scale for multi=ple> weighing platforms, having the calibration data stored in non-volatile > memory (eeprom, flash). =A0This way I can use the scale display for reloa=ding> scales or weighing machinery just by selecting the scale I'm currently > plugged into. > > Thought maybe some here may know of a good way to get load cell or strain > gage signals into a microcontroller like an Arduino. > > Thanks > > RogerNHave you chosen a load cell yet? Have you found any that cost about the same as an Arduino? From what I have seen so far the AD7730 looks very promising. Howard
Reply by ●March 3, 20122012-03-03
On Sun, 04 Mar 2012 00:11:07 +0000, Nico Coesel wrote:> "krw@att.bizzzzzzzzzzzz" <krw@att.bizzzzzzzzzzzz> wrote: > >>On Sat, 03 Mar 2012 23:37:43 GMT, nico@puntnl.niks (Nico Coesel) wrote: >> >>>"Martin Riddle" <martin_rid@verizon.net> wrote: >>> >>> >>>>"RogerN" <regor@midwest.net> wrote in message >>>>news:XpadnaQ-Q5YXAc_SnZ2dnUVZ_s6dnZ2d@earthlink.com... >>>>> >>>>> "Tim Wescott" wrote in message >>>>> news:qLmdnfK-LczQ68_SnZ2dnUVZ_hydnZ2d@web-ster.com... >>>>> >>>>>>On Sat, 03 Mar 2012 11:33:42 -0600, RogerN wrote: >>>>>>> >>>>>>><snip> >>>>>> >>>>>>Try doing some directed looking for applications notes showing how >>>>>>to use >>>>>>an ADC with a load cell. Hooking up the ADC to the Arduino is a >>>>>>separate >>>>>>problem which (hopefully) will be much more routine for you. >>>>>> >>>>>>-- >>>>>>Tim Wescott >>>>>>Control system and signal processing consulting >>>>>>www.wescottdesign.com >>>>>> >>>>>> >>>>> Most of what I have seen is to run the load cell through an >>>>> instrumentation amp then to the A/D. I have used the Arduino with a >>>>> serial 12 bit A/D before, LTC1298 if I remember correctly. I'm >>>>> wanting as high of resolution as practical, having found oversized >>>>> >>>>> >>>>Oversample a 16-bit ADC, acquisition time will be slow. But you can >>>>get 18 or 20 bits resolution if speed is not an issue. >>> >>>I doubt that. You can't get more bits out of an ADC. Its better to get >>>rid of the noise in the analog domain and be able to use the full >>>resolution. >> >>Sure you can. Averaging will give more bits than there is hardware for. >> I played that game with Tektronix digitizers 35 years ago, to pull >>signals out of the digitization noise. The number of bits gained >>(assuming uncorrelated noise) is proportional to the log of the number >>of samples, so it gets boring fast, though. ;-) > > That only works if there is enough noise to flip at least the LSB bit. > If the signal sits somewhere between 2 codes you can oversample all you > want but you'll never get any extra bits of resolution.Any monolithic DAC that's in the upper right corner of the speed and bit- count plot will have significantly more than one LSB of noise. So there is plenty of opportunity to enhance the resolution of the system by averaging. But resolution and accuracy are different things -- while noise averaging does, indeed, cut down on the quantization noise, it won't do much at all for integral nonlinearity error. There are 24-bit sigma-delta ADCs that would be perfect for this and are (I'm pretty sure) inexpensive -- I'd start with one of those, and go from there. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
Reply by ●March 4, 20122012-03-04
On Sun, 04 Mar 2012 00:11:07 GMT, nico@puntnl.niks (Nico Coesel) wrote:>"krw@att.bizzzzzzzzzzzz" <krw@att.bizzzzzzzzzzzz> wrote: > >>On Sat, 03 Mar 2012 23:37:43 GMT, nico@puntnl.niks (Nico Coesel) wrote: >> >>>"Martin Riddle" <martin_rid@verizon.net> wrote: >>> >>>> >>>>"RogerN" <regor@midwest.net> wrote in message >>>>news:XpadnaQ-Q5YXAc_SnZ2dnUVZ_s6dnZ2d@earthlink.com... >>>>> >>>>> "Tim Wescott" wrote in message >>>>> news:qLmdnfK-LczQ68_SnZ2dnUVZ_hydnZ2d@web-ster.com... >>>>> >>>>>>On Sat, 03 Mar 2012 11:33:42 -0600, RogerN wrote: >>>>>>> >>>>>>><snip> >>>>>> >>>>>>Try doing some directed looking for applications notes showing how to >>>>>>use >>>>>>an ADC with a load cell. Hooking up the ADC to the Arduino is a >>>>>>separate >>>>>>problem which (hopefully) will be much more routine for you. >>>>>> >>>>>>-- >>>>>>Tim Wescott >>>>>>Control system and signal processing consulting >>>>>>www.wescottdesign.com >>>>>> >>>>> >>>>> Most of what I have seen is to run the load cell through an >>>>> instrumentation amp then to the A/D. I have used the Arduino with a >>>>> serial 12 bit A/D before, LTC1298 if I remember correctly. I'm >>>>> wanting as high of resolution as practical, having found oversized >>>>> >>>> >>>>Oversample a 16-bit ADC, acquisition time will be slow. But you can get >>>>18 or 20 bits resolution if speed is not an issue. >>> >>>I doubt that. You can't get more bits out of an ADC. Its better to get >>>rid of the noise in the analog domain and be able to use the full >>>resolution. >> >>Sure you can. Averaging will give more bits than there is hardware for. I >>played that game with Tektronix digitizers 35 years ago, to pull signals out >>of the digitization noise. The number of bits gained (assuming uncorrelated >>noise) is proportional to the log of the number of samples, so it gets boring >>fast, though. ;-) > >That only works if there is enough noise to flip at least the LSB bit. >If the signal sits somewhere between 2 codes you can oversample all >you want but you'll never get any extra bits of resolution.Crunch all you want, we'll make more.
