Table of Contents

Signal/Preamp Issues

If the signal is too high (saturated) or too low, the preamp gain can be adjusted with the trimpot on the preamp PCB. Clockwise increases the gain, counter-clockwise decreases the gain. Note that adjusting the gain will necessitate a new calibration, so avoid adjusting if possible! The DAQ card has a maximum signal of +/- 1V.
Similarly, the PD gain can be adjusted with the trim pot on the side of the PD (look for the hole in the case). Again, this is typically rolled into the calibration and should not be adjusted unless absolutely necessary.

Serial Connection Issues

The following error indicates the serial device is in use by another program, there was a hangup at the serial port, or that the serial device did not shut down correctly:
```
ERROR: libserialport returned SP_ERR_FAIL - Host OS reported a failure.
```
If the device is connected via another program (e.g. Arduino Serial Monitor or Minicom), close that connection and shut down the program. Otherwise, trying to run the program again is usually sufficient to clear the error. If the error does not clear itself after 3 or 4 tries, reset the serial device by unplugging the USB cable and plugging it back in.