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PGA309EVM-USB is losing calibration

Danilo Carvalho
Prodigy 90 points
Other Parts Discussed in Thread: PGA309EVM-USB, PGA309

Hello,

I need to use PGA309 to acquire signal from a strain gauge. To do this I am using PGA309EVM-USB. I tested all functions of this EVM and everything is working well.

But in my final test I need to acquire signal with a third acquisition board because the large number of samples.

So I disconnected the USB-DAQ and I am using only the conditioning signal board. To do this I applied Vcc to the J1 connector (PIN 17:Vdut, 5V,JMP11:Vdut Power) and pulled down  J2 pin 2(CTRL) to gnd.

But after some hours or days the system loses calibration and I need to reconfigure the PGA. I did the test in another EVM and the same situation happens.

What could be happening?

Thanks,

Danilo Americano de Carvalho.

  • 0
    TI__Mastermind 22177 points

    This can happen from noise coupled into the PRG pin is interpreted as a digital signal.  I recommend setting the OWD (Register 4, bit D15) bit high.  Also using a 10k ohm pull-up resistor on PRG is helpful.  If you follow these two precautions, you should not see the corruption issues.

    Art Kay

  • 0
    TI__Mastermind 22177 points

    Danilo,

    I think I've answered this on a different post.  Let me know if you ahve resolved the problem. 

    This can happen from noise coupled into the PRG pin is interpreted as a digital signal.  I recommend setting the OWD (Register 4, bit D15) bit high.  Also using a 10k ohm pull-up resistor on PRG is helpful.  If you follow these two precautions, you should not see the corruption issues.

    Best regards,

    Art Kay