ADS130E08 manual sampling trouble

Yoel X. Peralta Mamoli

Other Parts Discussed in Thread: ADS130E08

Hi! I´m designing a power quality disturbances detector and recorder using the ADS130E08 as analog front-end, but I have some trouble making it work. I follow the steps of the flowchart that appear in page 45 of the datasheet, and I can see a 8kHz signal in the DRDY pin. But when I try to get samples at 6.4 kHz holding the START pin low and sending the START command every 156 us or sending a 6,4kHz squarewave (50% duty cycle) to the START pin, I have not got any response in the DRDY pin.

The aim is sampling the power line at 6.4 kHz. What am I doing wrong?

Thanks.

Yoel.-

over 12 years ago

0 Greg Hupp over 12 years ago

TI__Mastermind 23235 points

Please review the START section of the datasheet for details on the operation. Page 28

There is a settling time delay that you may not be accounting for; see settling time that is base on the datarate setting you are operating in. Keep in mind that by using the START pin, you are resetting the digital filter of the device every time and thus the settling time delay.

0 Yoel X. Peralta Mamoli over 12 years ago in reply to Greg Hupp

Prodigy 30 points

Thanks Greg for the answer. So if I have to wait the settling time after sending the START command, that is 1160 tclk (566 microseconds if Fclk = 2.048 MHz) I can not achieve the sampling frequency required of 6.4 kHz (T = 156 microseconds). That is right?

Thanks again!

0 Greg Hupp over 12 years ago in reply to Yoel X. Peralta Mamoli

TI__Mastermind 23235 points

Can you run the sampling at a higher rate and then decimate the data that you receive to get your desired frequency?

0 Yoel X. Peralta Mamoli over 12 years ago in reply to Greg Hupp

Prodigy 30 points

Yes, it is another option, but I need to sample at a frequency multiple of 6.400 Hz but the ADS130E08 maximum sample rate is 8 kSPS. ADS131Exx maximum sample rate is 64 kSPS. Probably I need to use that product of the family.

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ADS130E08 manual sampling trouble