Thermistor Interface; Analog Outputs - Teledyne 100E Instruction Manual

Model 100E Instruction Manual Theory Of Operation
PMT TEMPERATURE: This signal is the output of the thermistor attached to the PMT cold
block amplified by the PMT temperature feedback circuit on the PMT preamp board. It is
digitized and sent to the CPU where it is used to calculate the current temperature of the
PMT.
This measurement is stored in the analyzer. Memory as the test function PMT TEMP and
is viewable as a test function (Section 6.2.1) through the analyzer's front panel.
SAMPLE GAS PRESSURE SENSOR: This sensor measures the gas pressure at the exit of
the sample chamber.
SAMPLE FLOW SENSOR: This sensor measure the flow rate of the sample gas as it exits
the sample chamber.

10.4.10.3. Thermistor Interface

This circuit provides excitation, termination and signal selection for several negative-
coefficient, thermistor temperature sensors located inside the analyzer. They are:
SAMPLE CHAMBER TEMPERATURE SENSOR: The source of this signal is a thermistor
imbedded in the of the sample chamber block. It measures the temperature of the
sample gas in the chamber. This data are used by the CPU to control sample chamber
the heating circuit and as part of the SO , calculations when the instrument's
2
Temperature/Pressure Compensation feature is enabled.
This measurement is stored in the analyzer. Memory as the Test Function RCEL TEMP
and is viewable as a test function (Section6.2.1) through the analyzer's front panel.
IZS OPTION PERMEATION TUBE TEMPERATURE SENSOR: This thermistor, attached to the
permeation tube in the IZS option, reports the current temperature of that tube to the
CPU as part of control loop that keeps the tube at a constant temperature.
BOX TEMPERATURE SENSOR: A thermistor is attached to the motherboard. It measures
the analyzer's inside temperature. This information is stored by the CPU and can be
viewed by the user for troubleshooting purposes through the front panel display. This
measurement is stored in the analyzer. Memory as the test function BOX TEMP and is
viewable as a test function (Section 6.2.1) through the analyzer's front panel.

10.4.11. Analog Outputs

The analyzer comes equipped with four Analog Outputs: A1, A2, A4 and a fourth that is
a spare.
A1 and A2 Outputs: The first two, A1 and A2 are normally set up to operate in parallel
so that the same data can be sent to two different recording devices. While the names
imply that one should be used for sending data to a chart recorder and the other for
interfacing with a datalogger, either can be used for both applications.
Both of these channels output a signal that is proportional to the O3 concentration of the
Sample Gas. The A1 and A2 outputs can be slaved together or set up to operated
045150102 Rev XB1 187