myRIO analog voltage reference

[ghattas.akkad]

Hello,

I am looking to aquire analog input from an LM35 sensor to myRIO 1900, as per the datasheet the analog input channels on the MXP B support a measurment range of 0-5 V with 12-bit ADC resolution.

the LM35 sensor outputs a voltage of 0-1V with 10mV per C

previously in PIC or other microcontrollers design a ADREF+ and ADREF- is present on the hardware to choose the conversion reference voltage

since there is no ADREF pins in myRIO is it possible to control the reference voltage of a given pin for NI MAX or from an IO property/method node?

I tried using the method node for the AI input on MXP B but it has no methods, the property node showed two options none of them can be changed to "write" so I can set up a conversion between 0-1V reference and utilize the 12-bit resolution effieciently

Thank you

[arevh]

NI myRIO does not allow to change the range of analog input channels. For the MXP connectors' analog inputs it is fixed to be 0-5V. It does not have also control for reference voltage. So the LSB is fixed and is equal to 5/(2^12), which is ~1.2mV.

What accuracy do you need for your application? BTW the accuracy of LM35 is typically +/-0.2 °C according the datasheet.

Thanks,

Arev

CTO | RAFA Solutions

[crossrulz]

Use an op-amp to amplify your signal to the 0-5V range.

[ghattas.ak]

Hello and thank you

I was just curious about the availabilty of such option to change and control the REF voltages I am only using the LM35 for testing purposes

[ghattas.ak]

Thank you the reading is accurate enough on the 0-1V volts I just wanted an answer to be sure if I can control the REF or not