48
Calibration Frequency Recommendations
In-Situ sensors are factory calibrated across the entire range of each sensor, and thus achieve a very high
degree of accuracy and stability for extended periods of time without user calibration. In-Situ recommends
inserting the instrument into a known calibration standard to check the accuracy of a sensor prior to
performing any user calibration if you suspect drift, unless a user calibration is required by a standard
operating procedure.
Sensor
Recommended User
Calibration Frequency
Recommended Factory
Calibration Frequency
Notes
Conductivity
Only when required by
user protocol
12 months
K-cell value: 0.7 to 1.3
Conduc
Temperature
Only when required by
user protocol
12 months
K-cell value: 0.7 to 1.3
pH
10 to 12 weeks or as
required by user protocol
or site conditions
12 months
Single point:
Theoretical mV ±30 mV
2- or 3-point Slope:
-66 to 50 mV/pH
2- or 3-point Offset:
±30mV at pH 7
ORP
10 to 12 weeks or as
required by user protocol
or site conditions
12 months
Offset: ±30 mV
RDO
12 months or as required
by user protocol
12 months
2-point Slope:
0.7 to 1.3
2-point Offset:
±0.3 mg/L
Temperature
Only when required by
user protocol
Only when required
by user protocol
Offset: ±0.5
Turbidity
Only when required by
user protocol
12 months
Slope: 0.7 to 1.3
Pressure/Depth
Only when required by
user protocol
Only when required
by user protocol
<2 times the full scale
accuracy specification
Barometer
Only when required by
user protocol
Only when required
by user protocol
<2 times the full scale
accuracy specification
Ammonium
Monthly
N/A
Slope > 20 mV/decade
Chloride
Monthly
N/A
Slope < -20 mV/decade
Nitrate
Monthly
N/A
Slope < -20 mV/decade
1-970-498-1500
www.in-situ.com