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mccdaq / daqhats

MCC DAQ HAT Library for Raspberry Pi
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I want to use the MCC118 with different sampling rates per channel. #57

Closed gousekid closed 1 year ago

gousekid commented 1 year ago

Is it correct that the MCC 118 has a maximum sampling of 100kHz? If so, I would like to use 50khz, 10khz, 10khz and so on for the 3 channels. Is this possible?

nwright-mcc commented 1 year ago

The max sampling rate is 100kHz, but the hardware does not support different rates for different channels.

gousekid commented 1 year ago

Thank you for your kind answer. I have one more question. Using the python example you provided, the data I get is often duplicate (different rows, but consecutive values), isn't that an invalid data value?

example: 4.849269112 4.849269112 4.84414576 4.84414576 4.84414576 4.839022407 4.839022407 4.839022407 4.833899054 4.839022407 4.839022407 4.833899054 4.833899054 4.833899054 4.828775702 4.823652349 4.828775702 4.828775702 4.833899054 4.833899054 4.833899054 4.828775702 4.828775702

nwright-mcc commented 1 year ago

No, it is not uncommon to have consecutive samples on the same channel with the same value in a 12-bit system. At a +/- 10V input range each bit is 4.88mV, so if the signal changes by less than that amount the ADC reading may not change.