O 2 Sensor Is Not Reading - Siemens LMV5 Series Technical Instructions

LMV Series
If the O value on the main screen is displayed as "XXXX", check the following:
2
1. Ensure that the QGO20 O
Params & Display > O2 Module > Configuration > O2 Sensor = QGO20
2. The PLL52 O module controls the QGO20 O
2
temperature of approximately 1292
o
1202 F. Check the temperature of the QGO20 sensor through the following menu path:
Params & Display > O2 Module > Process Data > QGO SensorTemp
If the temperature is below 1202 °F, check the heating load to the O
Params & Display > O2 Module > Process Data > QGO HeatingLoad
The maximum QGO heating load is 60%. If the heating load is at or near 60%, the QGO20
sensor temperature should be increasing. If it is, the O
temperature is over 1202 °F. If the temperature is not increasing, check the following:
 The stack velocity may be too high, thus cooling the sensor. The maximum stack
velocity is 33 ft / second.
 The wiring between the O
to Section 2 to check the wiring between the two devices.
 The heating element in the QGO20 O
resistance between terminals Q4 and Q5 on the QGO20 O
between 5 and 150 Ohms between these terminals. If there is an open circuit
between these two terminals, the heating element has been damaged and the
QGO20 O sensor needs to be replaced.
2
Note: The QGO20 sensor can take up to two hours to achieve operating temperature on the
initial startup.
SCC Inc.
O2 Sensor is Not Reading
sensor is activated through the following menu path:
2
sensor's heater to achieve a sensor
2
o
F. The sensor cannot read %O
sensor and the PLL52 O
2
sensor may be damaged. Measure the
2
Page 13
HOME
Technical Instructions
Document No. LV5‐1000
if the sensor is below
2
sensor:
2
sensor will begin reading once the
2
module may be incorrect. Refer
2
sensor. There should be
2
Section 7