5
- archive memory, which are entered automatically with reference to the real-time
records, including: the results of measurements of the concentration of the controlled
components, temperature, pressure, the generalized fact of errors with the marking
"E1"..."E9", the fact of switching on the gas analyzer, the fact of discharge of the battery of
the power supply. Archive memory is read-only;
- memory of episodic measurements, in which, at the operator's command
(immediately or with a delay of 30 s, if necessary, the delay time can be increased or
decreased in the range from 0 to 99 s immediately before the measurement) are recorded at
the time of recording the readings, including: the value of the measured concentration of
methane (or combustible gases, or oxygen, or carbon monoxide, or hydrogen sulfide), the
value of the ambient temperature, the value of atmospheric pressure, the value of the current
time, generalized fact error appearance marked "E1" ... "E9", record number.
2.12 The volume of the archive memory allows you to memorize the records fixed
with a set time interval of 2 minutes for 60 hours with continuous operation of the gas
analyzer. After the specified time, the newly entered records are stored in memory, erasing
(overwrite) the first.
2.13 The amount of memory for episodic measurements is 4000 records. At filling of
the specified volume new records are brought in a place of the first. It is possible to clear
(format) the memory of occasional measurements in the tuning mode of the gas analyzer.
2.14 The operator can request from the memory of occasional measurements any
record with all the recorded values in the record displayed on the screen.
2.15 Records from the archive memory and the memory of occasional measurements
can be sending to a personal computer via an infrared port.
3. Operation and description
3.1. The action of the gas analyzer on the channel for measuring the volume fraction
of methane (or methane-hydrogen mixture) is based on measuring the signal of a
thermocatalysis sensor. The gas analyzer uses a scheme of periodic supply of voltage to the
sensor with a period of 7.5 sec. and an algorithm for auto-correction of readings.
When the volume fraction of methane exceeds 5.0%, the gas analyzer automatically
switches to the regime of thermal conductivity measurement of the volume fraction of
methane in the range up to 100%.
The action of the gas analyzer on the channel for measuring the volume fraction of
carbon dioxide is based on the thermal conductivity method.
The action of the gas analyzer on the channels for measuring the volume fraction of
oxygen, carbon monoxide and hydrogen sulphide is based on the electrochemical
measurement method.
3.2 Appearance of the gas analyzer is shown in Figure 1.
