Section 7. Installation
intersects two known points sequentially entered in the
FieldCal()
KnownVar
parameter. Subsequent measurements are scaled with the same multiplier.
FieldCal()
Option 3
does not affect
offset
.
Some measurement applications do not require determination of offset.
Frequency analysis, for example, may only require relative data to characterize
change.
Example Case: A soil-water sensor is to be used to detect a pulse of water moving
through soil. A pulse of soil water can be detected with an offset, but sensitivity
to the pulse is important, so an accurate multiplier is essential. To adjust the
sensitivity of the sensor, two soil samples, with volumetric water contents of 10%
and 35%, will provide two known points.
Table 32.
Calibration Report for Water Content Sensor
CRBasic Variable
At Deployment
SimulatedWaterContentSignal
175
mV
KnownWC
10
%
SimulatedWaterContentSignal
700
mV
KnownWC
35
%
WCMultiplier
0.0476
%/mV
The following procedure sets the sensitivity of a simulated soil water-content
sensor.
1. Send CRBasic example
FieldCal() Multiplier
(p. 221)
to the CR1000.
2. To simulate the soil-water sensor signal, place a jumper wire between terminals
VX1
and
SE1
.
3. Simulate deployment-calibration conditions in two stages as follows:
a. Set variable
SimulatedWaterContentSignal
to
175
. Set variable
KnownWC
to
10.0
.
b. Start the calibration by setting variable
CalMode
=
1
.
c. When
CalMode
increments to
3
, set variable
SimulatedWaterContentSignal
to
700
. Set variable
KnownWC
to
35
.
d. Resume the calibration by setting variable
CalMode
=
4
4. When variable
CalMode
increments to
6
, the calibration is complete.
Calibrated multiplier is
0.0476
.
CRBasic Example 43.
FieldCal()
Multiplier
'This program example demonstrates the use of FieldCal() in calculating and applying a
'multiplier only calibration. A multiplier calibration compares the signal magnitude of a
'sensor to known standards. The calculated multiplier scales the reported magnitude of the
'sensor to a value consistent with the linear relationship that intersects known points
'sequentially entered in to the FieldCal() KnownVar parameter. Subsequent measurements are
'scaled by the multiplier.
221
Summary of Contents for CR1000
Page 2: ......
Page 4: ......
Page 6: ......
Page 32: ......
Page 36: ......
Page 38: ......
Page 40: ......
Page 60: ...Section 4 System Quickstart Figure 16 PC200W View Line Graph 60 ...
Page 96: ......
Page 98: ...98 ...
Page 302: ......
Page 453: ...Section 8 Operation Figure 115 Using the Keyboard Display 453 ...
Page 456: ...Section 8 Operation Figure 118 Real Time Custom 456 ...
Page 457: ...Section 8 Operation 8 8 1 3 Final Memory Tables Figure 119 Final Memory Tables 457 ...
Page 458: ...Section 8 Operation 8 8 2 Run Stop Program Figure 120 Run Stop Program 458 ...
Page 460: ...Section 8 Operation Figure 122 File Edit 460 ...
Page 461: ...Section 8 Operation 8 8 4 PCCard Memory Card Display Figure 123 PCCard CF Card Display 461 ...
Page 478: ......
Page 506: ......
Page 536: ......
Page 636: ......
Page 642: ......
Page 644: ......
Page 676: ......
Page 677: ......