• Resolved

LMP91000: Wiring to a microcontroller, Arduino

Part Number: LMP91000

I previously had successfully wired the LMP91000 to an Arduino and successfully took reads that could be analyzed, plotted, etc.  However, it seems during the troubleshooting of one of the trials with the device, the wiring was not put back correctly and now the instrument continuously gives false readings that do not change according to the chemical environment. 

The current wiring is as follows:


LMP91000 Arduino
(Top Left) Extra pin GND
SCL SCL with Pull-Up
SDA SDA w/ Pull-Up
NC Not connected
VDD 3.3V
(Bottom left) Extra Pin GND
(Top Right) Extra pin GND
CE Out to CE
RE Out to RE
WE Out to WE
VREF Analog Write (3.3V)
VOUT A0 (Analog Read)
(Bottom Right) Extra pin GND

This arrangement apparently has not been working and I have tried two different TI chips, I've tested the Arduino analogWrite function and it writes beautifully accurate for the purposes of my project and other sources of error but cannot seem to come to the conclusion as to why this is not working anymore.  I used to perform cyclic voltammetry and got beautiful reads that fluctuated with the amount of voltage supplied to chemical solutions, but now, regardless of the voltage supplied, the reads come back, regardless of what chemical composition it is in, the same all the time, usually about 750 mV.  Code is fine, and the sensor is fine, I tried two different sensors.  I believe it is narrowed down to the cabling. 

Any help please?