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Troubleshooting and Service Teledyne API – Model T700 Dynamic Dilution Calibrator
248
9.2. USING THE ANALOG OUTPUT TEST CHANNEL
The signals available for output over the T700’s analog output channel can also be used
as diagnostic tools. See Section 4.7 for instruction on activating the analog output and
selecting a function.
Table 9-3: Test Channel Outputs as Diagnostic Tools
TEST
CHANNEL
DESCRIPTION ZERO
FULL
SCALE
CAUSES OF EXTREMELY
HIGH / LOW READINGS
NONE
TEST CHANNEL IS TURNED OFF
O3 PHOTO
MEAS
The raw output of the
photometer during its
measure cycle
0 mV 5000 mV*
O3 PHOTO
REF
The raw output of the
photometer during its
reference cycle
0 mV 5000 mV
If the value displayed is:
- >5000 mV: The UV source has become brighter; adjust the
UV Detector Gain potentiometer.
- < 100mV – Bad UV lamp or UV lamp power supply.
- < 2500mV – Lamp output has dropped, adjust UV Preamp
Board or replace lamp.
If the value displayed is constantly changing:
- Bad UV lamp.
- Defective UV lamp power supply.
- Failed I
2
C Bus.
If the PHOTO REFERENCE value changes by more than
10mV between zero and span gas:
- Defective/leaking M/R switching valve.
O3 GEN
REF
The raw output of the
O
3
generator’s
reference detector
0 mV 5000 mV
Possible causes of faults are the same as O3 GEN REFERENCE
WARNING from Table 9-1.
SAMPLE
PRESSURE
The pressure of gas in
the photometer
absorption tube
0 "Hg 40 "Hg-In-A Check for Gas Flow problems.
SAMPLE
FLOW
The gas flow rate
through the photometer
0 cm
3
/min 1000 cm
3
/m Check for Gas Flow problems.
SAMPLE
TEMP
The temperature of gas
in the photometer
absorption tube
0 C 70 C
Possible causes of faults are the same as PHOTO STEMP from
Table 9-2.
PHOTO
LAMP
TEMP
The temperature of the
photometer UV lamp
0 C 70 C
Possible failure of:
- Bench lamp heater
- Bench lamp temperature sensor
- Relay controlling the bench heater
- Entire Relay PCA
- I
2
C Bus
- Hot Lamp
O3 LAMP
TEMP
The temperature of the
O
3
generator’s UV
lamp
0 mV 5000 mV Same as PHOTO LAMP TEMP WARNING
from Table 9-1.
CHASSIS
TEMP
The temperature inside
the T700’s chassis
(same as BOX TEMP)
0 C 70 C
Possible causes of faults are the same as BOX TEMP from Table
9-2.
O3 PHOTO
CONC
The current
concentration of O
3
being measured by the
photometer.
- - -
- I
2
C Bus malfunction
- Gas flow problem through the photometer.
- Electronic failure of the photometer subsystems.
- Failure or pressure / temperature sensors associated with the
photometer.
- Bad/incorrect Span Gas concentration.
- Contamination of the Zero Air supply.
- Malfunction of the O
3
generator.
- Internal A/D converter problem.
06873B DCN6388