Using The Diagnostic Signal I/O Function - Teledyne T700 Operation Manual

Troubleshooting and Service
TEST FUNCTION
2
PH STEMP
2
PH SLOPE
2
PH OFFST
TIME
1
Only appears when the optional O
2
Only appears when the optional O

9.1.3. USING THE DIAGNOSTIC SIGNAL I/O FUNCTION

236
DIAGNOSTIC RELEVANCE AND CAUSES OF FAULT CONDITIONS.
The temperature of the gas in the photometer‟s sample chamber is used to calculate the
concentration of O in the gas stream. Incorrect sample temperature can cause inaccurate
3
readings.
Possible causes of faults are:
- Bad bench lamp heater
- Failed sample temperature sensor
- Failed relay controlling the bench heater
- Failed Relay PCA
- I 2
C Bus malfunction
- Hot lamp
Values outside range indicate:
 Contamination of the Zero Air or Span Gas supply.
 Instrument is miss-calibrated.
 Blocked Gas Flow.
 Faulty Sample Pressure Sensor or circuitry.
 Bad/incorrect Span Gas concentration.
Values outside range indicate:
 Contamination of the Zero Air supply.
Time of Day clock is too fast or slow.
 To adjust see Section 4.5.
 Battery in clock chip on CPU board may be dead.
generator is installed.
3
photometer is installed
3
The Signal I/O parameters found under the DIAG Menu combined with a thorough
understanding of the instrument‟s Theory of Operation (found in Section 0) are useful
for troubleshooting in three ways:

The technician can view the raw, unprocessed signal level of the calibrator‟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 calibrator. Figure 9-1 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 API – Model T700 Dynamic Dilution Calibrator
06873E DCN7106