comparison: ad7730 and ads1232

[arnab.bhaumik]

ads1232

hi all,
i just finished a weigh scale machine using ad7730 and at89c52. (with SDCC).

ad7730 is very good, huge count at 24 bit.
but the main problem is that it costs 11.50$(almost here in india). its a lot of money(almost 550 indian rupee).

after searching the net i found ads1232 from texas instrument. it is very cheap than ad7730. the cost of ads1232 is 3.9$.

my question is that both r 24 bit sigma-delta adc for load cell. but what is ther peformance comparison???

for parformance (counting and stability) ad7730 is really good.

experienced ppl please help......

arnab/vu2bpw

 

[attrish]

Hi arnab,
i got ads1232ref kit with me and its performance is pretty much acceptable. Where are you located , i've got a spare adc too, may be i can send you the kit for evaluation.

 

[mandar_mahajan]

Compare their respective datasheets. Their electrical characteristics , DC, etc.
This parameters are imp for comparing the two ADC's.

 

[arnab.bhaumik]

hi ,


for many years i have 4 sample of ad1232 with me, but i have done jewelery project with ad7730 and now doing other weighing scale with ca5460a.


i owned a SSI manufacturing unit of weighing scale. for the time being my next logical project is to make a analytical weighing scale with "electromagnetic_force_compensation" sensor and systems. in this system as far as i know .01mg resolution is possible .

need some suggestion in this matter. as the literature is also very little in the net.

arnab/vu2bpw

ps- i live in Kolkata, West Bengal

 

[attrish]

hi arnab,
I was there in W.B at haldia for 2.5 years, i've just started working on weighing scale application. I am designing the batch filler with ADS1232 but the support from TI is pathetic. I've already designed a 10bit adc for 500gms filler with mega8 avr & PLC too. The kit itself is a weing scale capable of measureing 0.001μg, too good as compared with satorious, metler or eassen scales costs around 80k inr.You can even analyze the noise & stability of the system itself. Now days i am nearby delhi.What i want to do is to interface it with mega8 avr & send the realtime measured voltage / weight to other avr over serial strings & process further. i want to keep minimum distance between loadcell & digitizer. possibly the whole ADC inside the loadcell housing.
You can read the manual regarding the kit. focus.ti.com/lit/ug/sbau120a/sbau120a.pdf

 

[arnab.bhaumik]

hi attrish,

are telling me the kit can measure .001ug or .001g???? if it is .001g also with the load cell, then the design of the kit is surely very good. but i really dont think that you r gettign a stable reading of 1mg from the load cell. and if you are getting please let me know. then i also like to evaluate the performance of the kit and its hardware design.

its based on the fact that after 1yr of trying i got stable effective reading of 10mg resolution from a 300g load-cell (adi make) using ad7730. what it seems that to achieve stability i had to undertake many changes in pcb design.

my e-mail id is arnab.bhaumik@gmail.com please drop a mail.

arnab/vu2bpw

 

[attrish]

hi arnab,
what i observed so far is, the kit needs a pure dc source. Stable power supply better are the results. infact power adopter vs 9vdc battery makes big difference. but the major flaw in my system was the loadcell itself. Its a 7kg loadcell & defective too along with the non availibility of calibration mass 5kg. So what i did was, i hooked up the high performance kit with defective loadcell ( non linear o/p) & calibrated with 1kg weight. Still it detects change in weight even if u put a calibration mass of 1mg.

( i borrowed calibration mass kit from a friend of mine from haldia when they uprgaded their lab scale to auto calibrate one VIBRA. they were using it to measure gsm of laminate.)

As you are into weight measurement professionally i have to recheck the system again. I'll try to get you the video of the kit & test by tomorrow.
Its been more then a month since i powered up the kit.