Teledyne 9110T - Nitrogen Oxides Analyzer - Manual (Page 267)

Model 9110T NOx Analyzer Troubleshooting & Service
Teledyne Analytical Instruments 267
TEST FUNCTION INDICATED FAILURE(S)
concentration incorrect; leaks
NOX OFFset Incorrect span gas concentration; low-level calibration off
NO SLOPE HVPS out of range; low-level calibration off; span gas concentration incorrect; leaks
NO OFFSet Incorrect span gas concentration; low-level calibration off
TIME Internal clock drifting; move across time zones; daylight savings time?
12.1.3. DIAG  SIGNAL I/O: USING 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 instrument’s principles of operation (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. Following is 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.