
B–70115EN/03
E. CONTROL SEQUENCES
IN LASER OSCILLATOR
APPENDIX
455
[SQ 294]
When normal base discharge is confirmed and PRM15000 bit 4 [200 bit
4] is 1 (power calibration is done), this sequence begins to obtain power
calibration coefficient. Power calibration is to calibrate so that real and
command powers become equal. The equation used is as follows.
PRM15204 [241] = Pc/Pa×1024 (2)
PRM15204 [241] : Power calibration coefficient
Pc : Command power
Pa : Actual power
The power calibration coefficient is calculated by outputting the value
specified with PRM 15200 (power used for power calibration when half
of the discharge tubes are used) or PRM 15201 (power used for power
calibration when all the discharge tubes are used) [PRM 230 for two
discharge tubes][PRM 231 for four discharge tubes][PRM 232 for eight
discharge tubes] then assigning that value to the above equation. The
actual power measured three minutes after the start of output is used as
Pa.
The difference between the specified power and actual power is also
monitored. The laser is judged as being normal provided the difference
is less than the value specified with PRM 15271 [242] (power decrease
limit).
The power calibration coefficient is clamped to the value specified for
PRM 15203 [240] (power calibration limit).
Once the above procedure has terminated normally, the laser enters the
LSTR state.