Campbell Scientific CR1000 Measurement and Control System - Manual (Page 156)

Section 7. Installation
156
Table 23. Calibration Report for Salinity Sensor
Parameter
Parameter at
Deployment
Parameter at 7-Day
Service
mV output 1350 mV 1345 mV
KnownSalt (standard
solution) 30 mg/l 30 mg/l
Multiplier 0.05 mg/l/mV 0.05 mg/l/mV
Offset -37.50 mg/l -37.23 mg/l
RH reading 30 mg/l 30 mg/l
1. Send the program in CRBasic example FieldCal Offset Demo Program
(p. 156)
to the CR1000. An excitation channel has been programmed to simulate a
sensor output.
2. To simulate the salinity sensor in deployment-calibration conditions (30 mg/l
standard solution), place a jumper wire between channels VX1/EX1 and SE6
(3L). Set variable mV to 1350. Set variable KnownSalt to 30.
3. To simulate the deployment calibration, change the value in variable CalMode
to 1 to start calibration. When CalMode increments to 6, offset calibration is
complete. Calibrated offset will equal -37.48 mg/l at this stage of the example.
4. To continue this example and simulate an offset-drift condition, change
variable mV to 1345.
5. To simulate 7-day, service-calibration conditions (30 mg/l standard solution),
set variable KnownSalt to 30.0. Change the value in variable CalMode to 1 to
start calibration. When CalMode increments to 6, 7-day, service-offset
calibration is complete. Calibrated offset will equal -37.23 mg/l.
CRBasic Example 27. FieldCal() Offset Demo Program
'Jumper VX1/EX1 to SE6(3L) to simulate a sensor
Public mV 'Excitation mV output
Public KnownSalt 'Known salt concentration
Public CalMode 'Calibration trigger
Public Multiplier 'Multiplier (starts at .05 mg / liter / mV,
'does not change)
Public Offset 'Offset (starts at zero, not changed)
Public SaltContent 'Salt concentration
'Data Storage Output of Calibration Data -- stored whenever a calibration occurs
DataTable (CalHist,NewFieldCal,200)
SampleFieldCal
EndTable