TELEDYNE API T100U, Дополнение к руководству по эксплуатации

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9. PRINCIPLES OF OPERATION
The T100U is a modified T100. The primary differences are the way in which the PMT
and UV reference signals are acquired and processed. The T100U has no shutter but
rather employs synchronous demodulation to capture the dark and light PMT and UV
reference signals several times per second. A printed circuit board, the Sync
Demodulator, attached to the end of the PMT housing, on the sensor assembly, includes
circuitry that digitizes the PMT and UV reference signals and synchronizes the operation
of the UV source with these measurements. This method of signal processing minimizes
the error that changing offsets could make in an instrument that is designed to operate
near its detection limit.
9.1 ELECTRONIC OPERATION
The following information is in addition to that contained in Section 13.5.2 of the T100
Manual.
9.1.1 SENSOR MODULE
At the heart of the T100U’s signal processing, illustrated in Figure 9-1 below, is the
Synchronous Demodulator PCA (Sync Demod board). The PCA is attached to the end
of the PMT housing and serves to seal the end of the PMT housing. The sync
demodulator controls the operation of the UV Lamp driver, digitizes the analog output
signals from the PMT UV reference detector and PMT temperature sensor, controls the
PMT cooler (thermo-electric cooler, TEC), controls the PMT HV via a local I2C bus,
and communicates with the analyzer’s CPU over the master I2C bus. Digitized and
processed data from the UV reference and PMT are passed to the analyzer’s CPU over
the master I2C bus and data for control of the PMT HV control DAC is passed from the
CPU to the DAC on the PMT preamp via the microcontroller on the Sync Demod board.
06840B DCN 6201