Teledyne gfc 7000ta Using the Diagnostic Signal I/O Function, Test Functions Slope Offset

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer

TEST

FUNCTIONS

SLOPE

OFFSET

INDICATED FAILURE(S)

Values outside range indicate

Contamination of the zero air or span gas supply Instrument is miss-calibrated

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. Values outside range indicate Contamination of the zero air supply Contaminated or leaking GFC wheel (either chamber) Faulty IR photo-detector

10.1.3. Using the Diagnostic Signal I/O Function

The Signal I/O parameters found under the DIAG Menu (See Section 6.9.2 and Appendix A) combined with a thorough understanding of the instrument’s Theory of Operation (found in Section 10) are useful for troubleshooting in three ways:

∙The technician can view the raw, unprocessed signal level of the analyzer’s critical inputs and outputs.

∙All 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 of the Analog and Digital Output signals.

This allows the technician to systematically observe the effect of directly controlling these signals on the operation of the analyzer. Below in Figure 11-2 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. The specific parameter will vary depending on the situation.

Teledyne Analytical Instruments 223