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Topic: ADS1234 : 24bits load cell adc (Read 1 time) previous topic - next topic

jujun

Hello,

I'am playing with an ADS1234 (it's a 24 bits adc made for load cell) and a load cell. I have already get this working with an ADS1231 chip. (same as ADS1234 but with only one input, the ADS1234 have 4).

The datasheet of the ADS1234 : http://www.ti.com/lit/ds/symlink/ads1232.pdf
The datasheet of the ADS1231 : http://www.ti.com/lit/ds/symlink/ads1231.pdf

With the ADS1234 the RDY pin don't goes low. So I can't read data.
One time yesterday it worked during 5 minutes. But I cant understand why.

Maybe the capacitor ?

I used one like this, of 100nF = 0.1µF

The chip is wired like this :
1 => VDD
2 => GND
3 => GND
4 => NC
5 => GND
6 => GND
7 => GND
8 => GND
9 => CAPACITOR
10 => CAPACITOR
11 => LOAD CELL OUT +
12 => LOAD CELL OUT -
13 => NC
14 => NC
15 => NC
16 => NC
17 => NC
18 => NC
19 => GND
20 => VCC
21 => GND
22 => VCC
23 => GND
24 => GND
25 => GND
26 => VCC
27 => NC or UC SPI SCLK
28 => NC or UC SPI MISO

What I am doing wrong ?
I need to take a global view.

What can I test ?

I have already tried with an another chip, but it don't change anything.

I must be something very stupid ....

Thanks for your help !

RIDDICK

maybe something gets stuck in the chip during power up?

what if u reset the chip after power up by pulling down pin 26 (-PDWN) and then up again?
-Arne

MarkT

[ I won't respond to messages, use the forum please ]

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