Instruction manual

12.0 TROUBLESHOOTING SM425 INSTRUCTION MANUAL
42500001 REV A 199
increases. Visually inspect the sensor for cracks. If any crack is found, replace the sensor
assembly. Cracks do not necessarily trigger an Error-1.
(Note) Data such as cell robustness displayed in the detailed data display should also be used for
.
< Causes and Corrective Actions >
acceptable fluctuations in measured process oxygen
crease in the moisture content of the calibration gases. A large change of moisture
This
mize fluctuations in oxygen
concentration due to moisture, use a reference gas whose moisture content is constant such as
instrument air. Small fluctuations can also be caused by changes in the moisture content of the
gas tubing. Verify
and the needle. Check solenoid valves used in automatic calibration.
s are fully closed.
ing in the sensor reducing the oxygen
te.
b. Check if the signal wiring or signal wires.
2.
ch, or breaker as other
ue to vibration or other factors if
cked or the sensor-mounting is leaking.
deciding sensor quality
12.3.2 Measured Value Lower Than Actual Value
1. The process gas pressure decreases. Un
concentration due to pressure changes can be minimized by taking the steps referred to in
subsection 12.3.1 (1).
2. Significant de
in reference air may cause an error in the measured oxygen concentration value (vol% O
2
).
may occur if ambient air is used as the reference gas. In order to mini
process gas.
3. Calibration gas (zero gas) is leaking into the detector through the calibration
the integrity of tubing joints
Confirm that manual valve
4. Combustible particulate in the process gas are burn
content. Check there are no combustible particula
5. Temperature of the detector cell reaches 750°C or more.
12.3.3 Intermittent Abnormal Measurements
< Causes and Corrective Actions >
1. Electrical noise on the detector output wiring.
a. Verify the converter and detector are electrically grounded.
is run with other power
The power supply is generating noise.
a. Check if the converter power is supplied from the same outlet, swit
equipment.
3. Poor wiring contact
a. Sensor voltage or thermocouple emf (voltage) may vary d
there is poor wiring contact.
b. Check for loose wiring connections or loose crimps on the crimp-on terminal lugs.
4. Combustible particulate in the process gas may be getting into the sensor.
a. Particulate filtering may be improved by using a dust-removing filter 96751017.
5. The sensor is cra
a. Check for a crack in the sensor or if the sensor-flange metal O-ring needs replacement.
6. The calibration gas tubing may be leaking.
a. A negative process pressure magnifies this cause.