LM35 and negativ values | LabJack
 

LM35 and negativ values

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speechsupply
speechsupply's picture
LM35 and negativ values

Hi, 

I would like to use the LM35 for a series of temp. measurements. 
My measurements will range from -20 C to +75 C. 

The U3 is good for down to -0.3 V, is that correct?  
What do I need to do, to enable negativ voltages on an Input? 
I'm using the LJLogUD program to capture data

LabJack Support
LabJack Support's picture
Connect your signal to FIO4

Connect your signal to FIO4 and jumper FIO5 to GND.  Set CH+=4 and CH-=5 to do a differential reading of AIN4-AIN5, and the range will be about -0.3 to +2.4 versus ground.

Note that special thought is required to get voltages <0 from the LM35.  Also note that we feel the LM34 is better than the LM35 because it provides more output and 0.0 volts is -17C.

https://labjack.com/support/app-notes/temperature-sensors