Operating Modes; Table 3-1. Proper 55018 Rear Panel Led Power-Up Sequence - HP 5501B Operating And Service Manual

3-10. OPERATING MODES

3-11. When power is applied to the HP5501B, an internal state machine resets the laser head to a
warmup mode. This mode is used to establish the initial operating temperature of a glass rod
that controls the laser cavity length. When this temperature is reached, the state machine
switches to an optical tuning mode. Upon successfully switching from warmup to optical mode,
the laser head enables the REFerence signal and lights a READY LED indicator on the rear panel
to indicate that the laser head is ready for use. The following table will give the proper operating
sequence for the HP5501B rear panel Led's from initial power-up (warmup mode) to when the
laser is ready to use (optical mode).

Table 3-1. Proper 55018 Rear Panel LED Power-up Sequence

LED's
+15V SUPPLY
UNBALANCE
(Red LED)
-15V SUPPLY
UNBALANCE
(Red LED)
+15V
FUSE OPEN
(Red LED)
-15V
FUSE OPEN
(Red LED)
+15V
POWER ON
(Green LED)
-15V
POWER ON
(Green LED)
READY
(Green LED)
LASER ON
(Amber LED)
15V Applied
to Laser
Head. Heater
Full On
*Time intervals reflect that laser tube was cold at turn-on; shorter times can be expected if tube is warm
at turn-on.
**Refer to paragraph 8-100 for further explanation of laser operating modes.
WARMUP
PREHEAT HEATER
QUALIFIED
←3-6 Min**→ ← 100 sec →
OFF
OFF
OFF
OFF
ON
ON
OFF Flashing 2Hz
OFF
↑ ↑
Glass rod
reaches
temperature
(begin 100
second
stabilization
period
OPERATING MODES*
LOCKING
← 50 sec →
OFF OFF
OFF OFF
OFF OFF
OFF OFF
ON ON
ON ON
Flashing
2Hz
OFF ON
↑
HVPS Turns Reference
on signal
Laser Beam present
on Laser now
ready for use
HP5501B
Operation
OPTICAL
LOCKED
Continuous use
OFF
OFF
OFF
OFF
ON
ON
ON
ON
↑
3-13