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:
Arduino
| LMP91000 | Arduino |
| (Top Left) Extra pin | GND |
| DGND | GND |
| MENB | 3.3V |
| SCL | SCL with Pull-Up |
| SDA | SDA w/ Pull-Up |
| NC | Not connected |
| VDD | 3.3V |
| AGND | AGND |
| (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) |
| C1 | GND |
| C2 | GND |
| 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?
