Teledyne T400, User Manual, Page: 131 / 177

083730400A DCN8130 Teledyne API – Model T400 O
3
Analyzer 129
5.7.10 M
OTHERBOARD
5.7.10.1 A/D FUNCTIONS
The simplest method to check the operation of the A-to-D converter on the motherboard
is to use the Signal I/O functions under the Utilities>Diagnostics menu to check the two
A/D reference voltages and input signals that can be easily measured with a voltmeter.
•
View the value of REF_4096_MV and REF_GND.
• If both are within 3 mV of nominal (4096 and 0), and are stable, ±0.5 mV then the
basic A/D is functioning properly. If not then the motherboard is bad.
•
Choose other parameters such as SAMPLE PRESSURE or SAMPLE FLOW,.
• Compare these voltages at their origin (refer to the interconnect drawing in Appendix
B) with the voltage displayed through the signal I/O function.
•
If the wiring is intact but there is a large difference between the measured and
displayed voltage (±10 mV) then the motherboard is bad.
See also Section 5.7.3.
5.7.10.2 STATUS OUTPUTS
1 2 3 8 4 D 5 6 7 +
V +DC Gnd
1000 Ω
SYSTEM_OK
Figure 5-13. Typical Set Up of Status Output Test
To test the Status outputs:
1. Connect a jumper between the “D“ pin and the “

” pin on the status output
connector.
2. Connect a 1000 ohm resistor between the “+” pin and the pin for the status output
that is being tested.
3. Connect a voltmeter between the “

” pin and the pin of the output being tested (see
table below).
4. In the Utilities>Diagnostics>Digital Outputs menu (see Section 5.7.3), scroll through
the outputs until you get to the output in question.
5. Alternatively, turn on and off the output noting the voltage on the voltmeter.
• It should vary between 0 volts for ON and 5 volts for OFF.