Campbell Scientific CR800 and CR850 Measurement and Control Systems - Manual (Page 155)

Section 7. Installation
155
1. Send CRBasic example FieldCal Zeroing Demonstration Program
(p. 155)
to the
CR800. An excitation channel has been programmed to simulate a sensor
output.
2. To place the simulated RH sensor in a simulated-calibration condition (in the
field it would be placed in a desiccated chamber), place a jumper wire between
channels VX1/EX1 and SE6 (3L). Set variable mV to 1000. Set variable
KnownRH to 0.0.
3. To simulate a calibration, change the value in variable CalMode to 1 to start
calibration. When CalMode increments to 6, zero calibration is complete.
Calibrated Offset will equal -50% at this stage of this example.
Figure 48: Zero (Option 0)
4. To continue this example and simulate a zero-drift condition, change variable
mV to 1050.
5. To simulate conditions for a 30-day, service-calibration, again with desiccated
chamber conditions, set variable KnownRH to 0.0. Change the value in
variable CalMode to 1 to start calibration. When CalMode increments to 6,
simulated 30-day, service zero calibration is complete. Calibrated Offset will
equal -52.5%.
CRBasic Example 26. FieldCal() Zeroing Demonstration Program
'Jumper VX1/EX1 to SE6(3L) to simulate a sensor
Public mV 'Excitation mV Output
Public KnownRH 'Known Relative Humidity
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 RH 'Measured Relative Humidity
'Data Storage Output of Calibration Data -- stored whenever a calibration occurs
DataTable (CalHist,NewFieldCal,200)
SampleFieldCal
EndTable
BeginProg
Multiplier = .05
Offset = 0
LoadFieldCal (true) 'Load the CAL File, if possible