Teledyne T100, Инструкция по эксплуатации, Страница: 276 / 404

Troubleshooting & Repair Teledyne ML - T100 UV Fluorescence SO2 Analyzer
276 06807A(DCNxxxx)
10.6.6. RELAY BOARD
The relay board circuit can most easily be checked by observing the condition of its status
LEDs as described in Section 10.2, and the associated output when toggled on and off
through the
SIGNAL I/O function in the DIAG menu, refer to Section 4.8.2.

If the front panel display responds to button presses and D1 on the relay board is not flashing,
then either the I
2
C connection between the motherboard and the relay board is bad, or the
relay board itself is bad.

If D1 on the relay board is flashing, but toggling an output in the Signal I/O function menu
does not toggle the output’s status LED, the there is a circuit problem, or possibly a blown
driver chip, on the relay board.

If D1 on the Relay board is flashing and the status indicator for the output in question (heater,
valve, etc.) toggles properly using the
Signal I/O function, but the output device does not turn
on/off, then the associated device (valve or heater) or its control device (valve driver, heater
relay) is malfunctioning.
Several of the control devices are in sockets and can easily be replaced. The table below
lists the control device associated with a particular function:
Table 10-6: Relay Board Control Devices
FUNCTION CONTROL DEVICE SOCKETED
Valve0
– Valve3
U5 Yes
Valve4
– Valve7
U6 Yes
All heaters K1-K5 Yes
10.6.7. MOTHERBOARD
10.6.7.1. A/D FUNCTIONS
A basic check of the analog to digital (A/D) converter operation on the motherboard is to
use the
Signal I/O function under the DIAG menu. Check the following two A/D
reference voltages and input signals that can be easily measured with a voltmeter. Using
the
Signal I/O function (refer to Section 4.8.2 and Appendix D), view the value of
REF_4096_MV and REF_GND .

The nominal value for REF_4096_MV is 4096 mV

10 mV.

The nominal value for REF_GND is 0 mV

3 mV, respectively, of their nominal values
(4096 and 0) and are

If these signals are stable to within ±0.5 mV, the basic A/D converter is functioning properly.

If these values fluctuate largely or are off by more than specified above, one or more of the
analog circuits may be overloaded or the motherboard may be faulty.

Choose one parameter in the Signal I/O function such as SAMPLE_PRESSURE (refer to
previous section on how to measure it). Compare its actual voltage with the voltage displayed
through the
SIGNAL I/O function. If the wiring is intact but there is a difference of more
than ±10 mV between the measured and displayed voltage, the motherboard may be faulty.