Teledyne 6200A Manual page 71

TAI Model 6200A SO Analyzer Operator Manual, 02164, Rev. G
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PMT Voltage
The PMT VOLTAGE measures the PMT signal at the output of the preamp board. The waveform of
the PMT voltage can be complex, and vary up to 5000 mV when a high concentration of SO is
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being measured. If the PMT reading is consistently 5000 mV, that indicates an off-scale reading.
Typical readings bounce around, which is normal.
UV Lamp
UV Lamp reading is the measurement voltage from the reference detector preamp board. Reference
detector is solar blind and facing directly into the UV lamp. Typical value is between 2000 mV and
4000 mV. The minimum acceptable level is 1000 mV.
Stray Light
Stray Light is the background light of the reaction cell expressed in ppb while sampling zero gas. It
is only the indication of condition of the optical system such as lenses, UV filter, light leak, etc.
Dark PMT
This dark current of the PMT is measured periodically to compensate any PMT dark current drift.
Typical value is near –50 + 200 mV.
Dark Lamp
This is the dark current of the UV reference detector which is used to compensate any dark current
drift. This measurement is synchronized to the Dark PMT measurement period. Typical value is near
–50 + 200 mV.
Slope
The coefficient of straight line equation (y=mx + b) determines the calibration of the 6200A. The
slope parameter (m) can be thought of as a gain term which determines the steepness of the
calibration curve.
Offset
The offset parameter (b) compensates for differences in the background signal of the optical system.
High Voltage Power Supply(HVPS)
The HVPS reading is a measure of the scaled-up HVPS programming voltage. The voltage used to
set the HVPS output is generated on the preamp board. Its value is between 0 and 1 volt,
corresponding to a voltage of 0 to 1000 volts out of the HVPS. The HVPS front panel TEST
measurement should be greater than 500 volts and will typically be around 550-900V.
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