Teledyne GFC7001T 12.1.3. THE DIAGNOSTIC SIGNAL I/O FUNCTION

Troubleshooting and ServiceTeledyne API – Model T300/T300M CO Analyzer
Teledyne Analytical Instruments 255
TEST
FUNCTIONS
(As Displayed) INDICATED FAILURE(S)
BOX TEMP If the box temperature is out of range, check fan in the power supply module. Areas to the side and rear of
instrument should allow adequate ventilation. See Table 12-1 for BOX TEMP WARNING.
PHT DRIVE
If this drive voltage is out of range it may indicate one of several problems:
 A poor mechanical connection between the photodetector, its associated mounting hardware and the
absorption cell housing;
 An electronic failure of the IR Photo-Detector’s built-in cooling circuitry, or;
 A temperature problem inside the analyzer chassis. In this case other temperature warnings would
also be active such as BENCH TEMP WARNING or BOX TEMP WARNING.
SLOPE
Values outside range indicate
Contamination of the zero air or span gas supply
Instrument is Miscalibrated
Blocked gas flow
Contaminated or leaking GFC Wheel (either chamber)
Faulty IR photo-detector
Faulty sample faulty IR photo-detector pressure sensor (P1) or circuitry
Invalid M/R ratio (see above)
Bad/incorrect span gas concentration due.
OFFSET
Values outside range indicate
Contamination of the zero air supply
Contaminated or leaking GFC Wheel (either chamber)
Faulty IR photo-detector
12.1.3. THE DIAGNOSTIC SIGNAL I/O FUNCTION
The signal I/O diagnostic mode allows access to the digital and analog I/O in the
analyzer. Some of the digital signals can be controlled through the touchscreen. These
signals, combined with a thorough understanding of the instruments Theory of
Operation (found in Section 13), are useful for troubleshooting in three ways:
 The technician can view the raw, unprocessed signal level of the analyzer’s critical
inputs and outputs.
 Many of the components and functions that are normally under algorithmic control
of the CPU can be manually exercised.
 The technician can directly control the signal level Analog and Digital Output
signals.
This allows the technician to observe systematically the effect of directly controlling
these signals on the operation of the analyzer. The following flowchart shows an
example of how to use the Signal I/O menu to view the raw voltage of an input signal or
to control the state of an output voltage or control signal. (See also Sections 5.9.1 and
12.5.8.1).