Teledyne 200AH 用户手册
Teledyne API Model 200AH NO
X
Analyzer Instruction Manual, 06492, Rev. G2
4-6
4.2.3. Pneumatic Sensor Board
The sensor board consists of 2 pressure sensors and a flow sensor. One pressure sensor measures
the pressure in the reaction cell. The reaction cell is maintained at about one-quarter of
atmospheric pressure. The second pressure sensor measures the pressure upstream of the reaction
cell, which is near ambient pressure. From these two pressures the sample flow rate can be
computed and is displayed as sample flow in the TEST menu. Finally, a solid state flow meter
measures the ozone flow directly. Likewise, it is displayed as a TEST function.
the pressure in the reaction cell. The reaction cell is maintained at about one-quarter of
atmospheric pressure. The second pressure sensor measures the pressure upstream of the reaction
cell, which is near ambient pressure. From these two pressures the sample flow rate can be
computed and is displayed as sample flow in the TEST menu. Finally, a solid state flow meter
measures the ozone flow directly. Likewise, it is displayed as a TEST function.
The M200AH displays all pressures in inches of mercury-absolute (in-Hg-A). Absolute pressure
is the reading referenced to a vacuum or zero absolute pressure. This method was chosen so that
ambiguities of pressure relative to ambient pressure can be avoided.
is the reading referenced to a vacuum or zero absolute pressure. This method was chosen so that
ambiguities of pressure relative to ambient pressure can be avoided.
For example, if the vacuum reading is 25" Hg relative to room pressure at sea level the absolute
pressure would be 5" Hg. If the same absolute pressure was observed at 5000 ft altitude where
the atmospheric pressure was 5" lower, the relative pressure would drop to 20" Hg, however the
absolute pressure would remain the same 5" Hg-A.
pressure would be 5" Hg. If the same absolute pressure was observed at 5000 ft altitude where
the atmospheric pressure was 5" lower, the relative pressure would drop to 20" Hg, however the
absolute pressure would remain the same 5" Hg-A.
4.2.4. Computer Hardware and Software
The M200AH Analyzer is controlled by a micro computer. The computers' multitasking
operating system allows it to do instrument control, monitor test points, provide analog output
and provide a user interface via the display, keyboard and RS-232 port. These operations appear
to be happening simultaneously but are actually done sequentially based on priority queuing
system maintained by the operating system. The jobs are queued for execution only when
needed, therefore the system is very efficient with computer resources.
operating system allows it to do instrument control, monitor test points, provide analog output
and provide a user interface via the display, keyboard and RS-232 port. These operations appear
to be happening simultaneously but are actually done sequentially based on priority queuing
system maintained by the operating system. The jobs are queued for execution only when
needed, therefore the system is very efficient with computer resources.
The M200AH is a true computer based instrument. The microprocessor does most of the
instrument control functions such as temperature control, valve switching. Data collection and
processing are done entirely in the CPU with the final concentration values being sent to a D/A
converter to produce the instrument analog output.
instrument control functions such as temperature control, valve switching. Data collection and
processing are done entirely in the CPU with the final concentration values being sent to a D/A
converter to produce the instrument analog output.
The computer memory is divided into 3 sections: ROM memory contains the multi-tasking
operating system code plus the instructions that run the instrument. The RAM memory is used to
hold temporary variables and current concentration data. The EEPROM memory contains the
instrument set-up variables such as range and instrument ID number. The EEPROM data is non-
volatile so the instrument can lose power and the current set-up information is preserved.
operating system code plus the instructions that run the instrument. The RAM memory is used to
hold temporary variables and current concentration data. The EEPROM memory contains the
instrument set-up variables such as range and instrument ID number. The EEPROM data is non-
volatile so the instrument can lose power and the current set-up information is preserved.