Other Parts Discussed in Thread: ADS127L11
Hallo
I have ADS127L11 eval board. What settings to reject 50,100 Hz ?
I use GUI provided by Ti, filter Sinc3+Sinc1
BR
Dim
After selecting internal clock, no 25.6 tab in G
sut up as you shown,
Now, by pressing "capture" it writes "capture in progress" about two minutes !
use 8k samples. result is single line. No noise track, no input signal
Hello Dim,
You can use either the SINC3 or the SINC3+SINC1 filters. The SINC3 will give you the highest data rate and input bandwidth.
In order to get 50Hz, 100Hz rejection, you need a main clock oscillator set to 25.6MHz. The evaluation board uses a 24MHz oscillator. However, the ADS127L11 has an internal oscillator with a typical 25.6MHz. This internal oscillator works well for low data rates of 480sps or less.
I suggest using the SINC3 filter, OSR=32000. Configure the ADS127L11 CONFIG4_REG to use the internal device oscillator, and select the divide by 8 clock option. You will then be able to get 50Hz and 100Hz rejection with an output data rate of 50sps. The internal oscillator has a tolerance of better than 2%, so you will get at least 100dB of rejection at 50/100Hz.
Regards,
Keith Nicholas
Precision ADC Applications
Hi Dim,
You can select the ADS127L11 internal clock using CONFIG4_REG. The internal clock frequency is 25.6MHz typical.
The GUI will not show the correct frequency; the above screen image is from a beta version. In your case, the MCLK setting in the GUI will display 24, but the internal clock will be operating at 25.6MHz.
Below is the correct image for the GUI version that you are using. 'Master Clock Freq (MHz)' displays 24, and 'Sampling Rate(sps)' displays 46.87, but the internal clock is operating at 25.6MHz and the resulting sample rate will be 50sps.
Sorry for the confusion.
Regards,
Keith
