
B-70315EN/02 5.TROUBLESHOOTING
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ALM No.4088
LASER VOLTAGE DOWN
This alarm is issued, if the voltage applied to the discharge tube
drops largely.
Alarm output condition
1) Immediately before the oscillation ready state (LSTR) is established,
the RF voltage of the power supply with the smallest number in the
selected discharge tubes is compared with the discharge tube
voltage in normal condition (parameter No. 15270). This alarm is
issued if the voltage has dropped by at least the allowable discharge
tube voltage drop. If the drop is less than the allowable drop, the RF
value at this time is stored in parameter No. 15270 as the discharge
tube voltage in normal condition.
2) During power compensation or in LSTR in which external power
control is not in progress, the RF voltage is compared with the
discharge tube voltage in normal condition (parameter No.15270). If
the voltage has dropped by at least the allowable discharge tube
voltage drop, another comparison is made in one second. This
alarm is issued if the state remains unchanged.
Related parameters
PRM.15270 Discharge tube voltage in normal condition
PRM.15272 Allowable discharge tube voltage drop
Related data
DGN.909-924 Discharge tube voltage and current
No. Cause of trouble Solution
1 Invalid parameter
setting
Check whether the values of PRM Nos. 15242,
15243, 15270, and 15272 are set as indicated in the
attached parameter table. If a different value is set,
set the value specified in the data sheets.
2 The laser gas
composition is not
as specified.
Replace the laser gas with specified laser gas.
3 Anomaly of
discharge tube
voltage detection
system
If discharge is performed, but the monitored
discharge tube voltage is extremely low, replace the
matching box.
4 Degradation of
turbo blower gas
circulating
performance
Check whether the turbo blower and high-frequency
inverter are normal. Replace the turbo blower or
inverter if found to be faulty.
ALM No.4089
ASSIST GAS NO SELECT
This alarm is issued when no assist gas is output during beam
output.
Alarm output condition
This alarm is issued, if an attempt is made to radiate a laser beam,
when no assist gas is selected, or an assist gas condition is not set up.
Related data
F222#0 to #2 Assist gas selection signal