Section 7. Installation
219
terminals
VX1
and
SE1
. The following variables are preset by the program:
SimulatedRHSignal
=
100
,
KnownRH
=
0
.
3. To start the 'calibration', set variable
CalMode
=
1
. When
CalMode
increments to
6
, zero calibration is complete. Calibrated
RHOffset
will equal
-
5
% at this stage of this example.
4. To continue this example and simulate a zero-drift condition, set variable
SimulatedRHSignal
=
105
.
5. To simulate conditions for a 30-day-service calibration, again with desiccated
chamber conditions, keep variable
KnownRH
=
0.0
. Set variable
CalMode
=
1
to start calibration. When
CalMode
increments to
6
, simulated 30-day-
service zero calibration is complete. Calibrated
RHOffset
will equal
-5.2
%.
FieldCal()
Zero
'This program example demonstrates the use of FieldCal() in calculating and applying a zero
'calibration. A zero calibration measures the signal magnitude of a sensor in a known zero
'condition and calculates the negative magnitude to use as an offset in subsequent
'measurements. It does not affect the multiplier.
'
'This program demonstrates the zero calibration with the following procedure:
' -- Simulate a signal from a relative-humidity sensor.
' -- Measure the 'sensor' signal.
' -- Calculate and apply a zero calibration.
'You can set up the simulation by loading this program into the CR800 and interconnecting
'the following terminals with a jumper wire to simulate the relative-humidity sensor signal
'as follows:
'
Vx1
---
SE
1
'For the simulation, the initial 'sensor' signal is set automatically. Start the zero routine
'by setting variable CalMode = 1. When CalMode = 6 (will occur automatically after 10
'measurements), the routine is complete. Note the new value in variable RHOffset. Now
'enter the following millivolt value as the simulated sensor signal and note how the new
'offset is added to the measurement:
' SimulatedRHSignal = 1000
'NOTE: This program places a .cal file on the CPU: drive of the CR800. The .cal file must
'be erased to reset the demonstration.
'DECLARE SIMULATED SIGNAL VARIABLE AND SET INITIAL MILLIVOLT SIGNAL MAGNITUDE
Public
SimulatedRHSignal =
100
'DECLARE CALIBRATION STANDARD VARIABLE AND SET PERCENT RH MAGNITUDE
Public
KnownRH = 0
'DECLARE MEASUREMENT RESULT VARIABLE.
Public
RH
'DECLARE OFFSET RESULT VARIABLE
Public
RHOffset
Summary of Contents for CR800 Series
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Page 446: ...Section 8 Operation 446 8 11 2 Data Display FIGURE 100 CR1000KD Displaying Data ...
Page 448: ...Section 8 Operation 448 FIGURE 102 CR1000KD Real Time Custom ...
Page 449: ...Section 8 Operation 449 8 11 2 3 Final Storage Data FIGURE 103 CR1000KD Final Storage Data ...
Page 450: ...Section 8 Operation 450 8 11 3 Run Stop Program FIGURE 104 CR1000KD Run Stop Program ...
Page 452: ...Section 8 Operation 452 FIGURE 106 CR1000KD File Edit ...
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Page 523: ...Section 11 Glossary 523 FIGURE 116 Relationships of Accuracy Precision and Resolution ...
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