measurements are still different after a second test, return to Campbell Scientific for recalibration
(see
page).
9.3 Troubleshooting
Symptom: –9999 or NAN readings
1. Check that the sensor is wired to the control or U terminal specified by the
SDI12Recorder()
instruction.
2. Check the voltage to the sensor with a digital voltage meter. If a switched 12V terminal is
used, temporarily connect the red wire to a 12V terminal (non-switched) for test purposes.
3. Verify the probe SDI-12 address matches the address entered for the
SDI12Recorder()
instruction. The address can be verified or changed with the commands described in
SN500SS Net Radiometer
14
