LMP91200: LMP91200 with Arduino

Farhaein Nasir

Part Number: LMP91200

Hello, I am trying to interface my LMP91200 to Arduino UNO R3. In what way should I connect my pins from the LMP91200 to Arduino UNO? Do I also need a special library for it?

Thanks

7 months ago

0 Ren Schackmann 7 months ago

TI__Mastermind 40825 points

Hi Farhaein,

The LMP91200 is an analog-only amplifier. There is nothing for an MCU to control or configure, so there is no associated software library. The VOUT and VOCM pins should be connected to the MCU's ADC or analog-input.

thanks,

ren

0 Farhaein Nasir 7 months ago in reply to Ren Schackmann

Prodigy 10 points

Thanks.

I am using LMP91200 with Arduino UNO R3 for pH measurement.

However, I understand that for VOUT. I just have to analogRead the pin to receive the value. For VOCM, I am trying to create a differential ADC for VOCM signal to remove the VREF influence. How would I connect it?

0 Ren Schackmann 7 months ago in reply to Farhaein Nasir

TI__Mastermind 40825 points

You want to make a differential measurement at the VOUT and VOCM pins. I'm not sure which pairs of pins on your Arduino are capable of differential measurements, if any.

thanks,

ren

0 Farhaein Nasir 7 months ago in reply to Ren Schackmann

Prodigy 10 points

Do I just need to set a float integer for the analog pin then I just read the value? I read the analogPIN and it give me a value of around 325 on the serial port. What does the value represent? I am a newbie so I am not entirely sure. my apologies

0 Ren Schackmann 7 months ago in reply to Farhaein Nasir

TI__Mastermind 40825 points

I'm not familiar with the Arduino output. Based on the LMP91200 datasheet, you should get a differential ADC result between -415 and +415mV. This may vary with different PH probe vendors. Check the documentation for your probe and check out page 15-16 of the LMP91200 datasheet.

thanks,

ren

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LMP91200: LMP91200 with Arduino