Michell Instruments QMA601, Руководство пользователя

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QMA601 User’s Manual
52 97449 Issue 3, June 2018
OPERATION
At the close of this 30 second sampling period, V1 is de-energized, and V2 is energized
so that the reference gas from the moisture generator is now routed to the sensor cell.
This is the beginning of the calibration phase, see
Figure 44.
The calibration reference gas is measured for a further 30 seconds, until V2 is de-
energized and the reference phase begins again.
The reference and sample paths are continually purged during each phase (as shown
by the green lines in Figure 44) during the calibration phase.
SAMPLE
IN
SAMPLE
OUT
DD
HE1 HE2
FC1 FC2 FC3
V1 V2 V3
MFC
QCH
PS
MG
Key
DD
Desiccant column
MG
Moisture generator
MFC
Mass flow controller
V1, V2, V3
Solenoid Valves
QCH
Sensor cell
HE1, HE2
Heat exchanger
PS
Pressure sensor
FC1, FC2, FC3
Flow control
Figure 44 Calibration Phase - Sample Flow
If an external calibration gas is used, the 'Cal Source' and 'Ext Ref' values should be
entered onto the Field Calibration screen (Section 3.6.4). The field calibration then
follows the same phases as used during a standard measurement cycle, as the internal
moisture generator is no longer required.
The analyzer will run though a number of 'settling cycles' to ensure the internal sample
system is fully equilibrated with the calibration gas before beginning to collect calibration
data.