01-22-2020 01:35 AM
Hi there,
I am trying to read a battery voltage (3.39 V) using 10bit-ADC (MCP3002 with SPI) by MyRIO 1900. I think I have connected everything correctly (plz see the attached). However, the output value is constant on 1023 which is equal to 2^10 (in other words, all the bits of ADC have one value (1111111111)), which is the completely wrong value. Also, the result (1023) will not change even if all the wires between ADC and MyRIO are disconnected. MyRIO .vi file and other pictograms are attached.
Please, is there anybody can tell me where is my mistake?
Thanks for any help in advance!
01-22-2020 04:14 AM
In SPI block,
1) I have changed the frame length from 10 bit to 16 bit as required in ADC datasheet.
2) I have tried SPI (0,0) mode and (1,1) mode.
3) MSB and LSB of the data direction have been tried.
4) i have measured the voltage for MISO and MOSI pins of MyRIO and the voltage for Do pin of ADC chip during the operational.
MISO = 3.2 V. is this normal?
MOSI = 0 V.
Do = 0.62 V.
But, unfortunately, there is no right result.
The output results are 1023 and 65535 when the frame length as 10 bit and 16 bit, respectively.
The expected result is 694 (1010110110).
Any idea, guys
thank you very much in advance