Campbell Scientific 109 109-L Temperature Probe - Page 20

Attributions and References

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Model 109 Temperature Probe 9.1 Troubleshooting Symptom: Temperature is reported as NAN, -INF, -9999, or -273. Recheck wiring. Verify the red wire is connected to the correct singleended analog input channel as specified by the measurement instruction, the black wire is connected to the switched excitation channel as specified by the measurement instruction, and the purple wire is connected to datalogger ground. Symptom: Incorrect temperature is reported. Verify the multiplier and offset arguments in the measurement instruction are correct for the desired units (Section 7.2, Datalogger Programming). Check the cable for signs of damage and possible moisture intrusion. Symptom: Unstable temperature is reported. Most likely a result of electromagnetic interference. Try using the 60 or 50 Hz integration options, and/or increasing the settling time as described in Section 8.3, Electrically Noisy Environments, and Section 8.4, Long Cable Lengths. Make sure the clear shield wire is connected to datalogger ground, and the datalogger is properly grounded. 9.2 Maintenance The 109 probe requires minimal maintenance. For air temperature measurements, check the radiation shield monthly to make sure it is clean and free from debris. Periodically check cabling for signs of damage and possible moisture intrusion. 9.3 Calibration Calibration of the 109 probe is not necessary unless the application requires removal of the thermistor interchangeability offset described in Section 6, Specifications. If performing the one point calibration with an Edlog datalogger, be aware of this precaution: The value of the offset must be chosen so that the probe outputs the temperature calculated by the polynomial, not the actual calibration temperature. For example, a 109 probe placed in a calibration chamber at 0 °C outputs 0.1 °C. An Offset argument of -0.08 is required for Edlog dataloggers because at 0 °C, the polynomial calculates a temperature of 0.02 °C (Appendix C, Conversion of Thermistor Resistance or Voltage Ratio to Temperature). 10. Attributions and References Santoprene® is a registered trademark of Exxon Mobile Corporation. EPA installation standard: Quality Assurance Handbook for Air Pollution Measurement Systems - Volume IV: Meteorological Measurements Version 2.0 WMO standard: WMO No. 8, Seventh edition, 6 Aug 2008 Guide to Meteorological Instruments and Methods of Observation 14

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Model 109 Temperature Probe
9.1
Troubleshooting
Symptom:
Temperature is reported as
NAN
,
–INF
,
–9999
, or
–273
.
Recheck wiring.
Verify the red wire is connected to the correct single-
ended analog input channel as specified by the measurement instruction,
the black wire is connected to the switched excitation channel as specified
by the measurement instruction, and the purple wire is connected to
datalogger ground.
Symptom:
Incorrect temperature is reported.
Verify the multiplier and offset arguments in the measurement instruction
are correct for the desired units (Section 7.2,
Datalogger Programming
).
Check the cable for signs of damage and possible moisture intrusion.
Symptom:
Unstable temperature is reported.
Most likely a result of electromagnetic interference.
Try using the 60 or
50 Hz integration options, and/or increasing the settling time as described
in Section 8.3,
Electrically Noisy Environments
, and Section 8.4,
Long
Cable Lengths
.
Make sure the clear shield wire is connected to datalogger
ground, and the datalogger is properly grounded.
9.2
Maintenance
The 109 probe requires minimal maintenance.
For air temperature
measurements, check the radiation shield monthly to make sure it is clean and
free from debris.
Periodically check cabling for signs of damage and possible
moisture intrusion.
9.3
Calibration
Calibration of the 109 probe is not necessary unless the application requires
removal of the thermistor interchangeability offset described in Section 6,
Specifications
.
If performing the one point calibration with an Edlog
datalogger, be aware of this precaution:
The value of the offset must be chosen so that the probe outputs the
temperature calculated by the polynomial, not the actual calibration
temperature.
For example, a 109 probe placed in a calibration chamber at 0
°
C
outputs 0.1
°
C.
An
Offset
argument of
–0.08
is required for Edlog dataloggers
because at 0
°
C, the polynomial calculates a temperature of 0.02
°
C (Appendix
C,
Conversion of Thermistor Resistance or Voltage Ratio to Temperature
).
10. Attributions and References
Santoprene
®
is a registered trademark of Exxon Mobile Corporation.
EPA installation standard:
Quality Assurance Handbook for Air Pollution
Measurement Systems – Volume IV: Meteorological Measurements Version 2.0
WMO standard:
WMO No. 8, Seventh edition, 6 Aug 2008 Guide to
Meteorological Instruments and Methods of Observation
14