Bio-Science CI-900, Руководство по эксплуатации

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CI-900 Instruction Manual 8/10/2015
1554 NE 3
rd
Ave, Camas, WA 98607, USA Phone: (360) 833-8835
sales@ cid-inc .com www.cid-inc.com
34
Setup Calibration
Current Calibration Parameters and re-calibration steps for C
2
H
4
, CO
2
, and O
2
sensors can be found
in the Calibration Menu. Press Enter to confirm and get into the menu. The options at the
Setup>Calibration menu are C
2
H
4
, CO
2
, O
2
, system DAC and flow.
C
2
H
4
Calibration
**Re-calibration or changes to any of the Calibration Parameters for C
2
H
4
must be performed
under the supervision of a CID Technician only.**
The options from the C
2
H
4
Calibration menu are for the C
2
H
4
PPM sensor, C
2
H
4
PPB, offset
autocorrection or sensitivity correction. Calibration Parameters are set by a CID Technician during
factory calibration and are specific to each instrument. The internal offset is the ADC voltage output
from the sensor when no ethylene is present, and gain describes the linear increase in the ADC
voltage output from the sensor in the presence of ethylene. The RH, T slope and offset are applied to
the ADC voltage to correct for shifts in relative humidity and temperature that may occur during the
sample period.
The ethylene sensor calibration will drift over time. Occasional recalibration of the sensors can be
carried out using calibration gas in the range of each ethylene sensor. For example, 1 ppm C
2
H
4
gas
can be used to adjust the internal gain reading for the C
2
H
4
PPB sensor. To adjust the internal gain
of the C
2
H
4
PPM sensor, standard gas between 5-100 ppm could be used. The timeframe for
adjusting the gain depends on the specific sensor and its use. The C
2
H
4
PPB sensor may require
weekly gain adjustments, while the C
2
H
4
PPB sensor may require gain adjustments every 6 months.
Manual Gain (Span) Calibration
It is recommended to use the more automated calibration of the CI-900 sensors, as described in the
Setup>Connection section on page 50.
Always perform a zero calibration of the ethylene
sensors using KMnO
4
before adjusting the gain. Run the calibration gas for at least 15 minutes to
ensure correctly reading calibration standard. Use the following formula to find the new internal
gain and update it in the Calibration Parameters menu, where solving for “x” is the new internal
gain. The measured concentration is what the CI-900 is reading the calibration gas as. Do not use
the Chamber In with water when performing calibrations.
Calibration Parameters
Internal offset
Internal gain
Calibrated RH
Calibrated t
RH slope
RH offset
t slope
t offset