7-46 
TOF-Ratio Over 
Range 
Low 
ST-Ratio measurement is 
out of range. 
1. Recalibrate the sensor. 
2. If the alarm persists, replace the 
DBS-Ratio Over 
Range 
Low 
TOF-Ratio measurement 
is out of range. 
1. Recalibrate the sensor. 
2. If the alarm persists, replace the 
 
7.4 Typical Troubleshooting 
7.4.1 Failure to Exit the Standby Mode 
Cause Confirmation 
Solution 
Failure to exit 
the standby 
mode 
1. Check whether the gas 
supply is sufficient. 
pressure is less 
than 280 kPa (40 
Connect or replace the gas 
supply. 
2. Use the touchscreen and 
encoder for the main screen to 
tap the Exit Standby softkey. 
to respond to the 
touchscreen 
2. If the problem persists, 
replace the display (refer to 
to respond to the 
encoder 
2. If the problem persists, 
replace the encoder (refer to 
The system does 
to respond to both 
the touchscreen 
and encoder 
operations. 
1. If other operations are 
also unavailable, replace the 
CPU board (refer to 
11.1.1). 
2. If other operations are 
available, perform step 3 to 
3. Check whether the system 
selftest succeeds. 
The system 
selftest fails. 
Refer to 7.3.1. 
4. Check whether a technical 
alarm is generated. 
A technical alarm 
is generated. 
Refer to 7.3. 
 
7.4.2 Auto/Manual Switchover Failure 
Cause Confirmation  Confirmation Result  Solution 
Failure to turn 
the auto/manual 
switch 
Observe whether there is dirt 
or debris in the gap of the 
auto/manual switch. 
There is dirt or debris. 
Clean the 
auto/manual switch. 
There is no dirt or debris, 
or the problem persists 
auto/manual switch 
Manual Only 
displayed on the 
screen 
Check whether the system 
selftest succeeds. 
The system selftest fails.  Refer to 7.3.1. 
Check whether the leak test 
succeeds. 
The leak test fails.  Refer to 4.2.3. 
after the 
Check whether the gas supply 
is sufficient. 
The gas supply pressure is 
less than 280 kPa. 
Connect or replace 
the gas supply.