Teledyne 9110T Diag  Signal I/O Using the Diagnostic Signal I/O Function, Indicated Failures

Model 9110T NOx Analyzer Troubleshooting & Service

TEST FUNCTION

NOX OFFset

NO SLOPE

NO OFFSet

TIME

INDICATED FAILURE(S)

concentration incorrect; leaks

Incorrect span gas concentration; low-level calibration off

HVPS out of range; low-level calibration off; span gas concentration incorrect; leaks Incorrect span gas concentration; low-level calibration off

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.

Teledyne Analytical Instruments 267