Agilent Technologies 5517B Operation And Service Manual page 35

3-11. When power is applied to the HP 5517B, 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 the READY LED
indicator on the rear panel to indicate that the laser head is ready for use. The following table gives the proper
operating sequence for the HP 5517B rear panel LEDs from initial power-up (warmup mode) to when the laser is
ready to use (optical mode).
Table 3-1. Proper 5517B Rear Panel LED Power-up
Sequence
LEDs
+15V
POWER ON
(Green LED)
-15V
POWER ON
(Green LED)
READY
(Green LED)
LASER ON
(Amber LED)
Laser Head, Heater Full On, HVPS Turns On,
Laser Beam On,
Laser Cavity Length Controlled By Monitoring
Warmup Error Amplifier Output.
Stabilization Period)
* 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 8-99 for further explanation of laser operating modes.
3-12. Warmup Time Operating Notes
• Allow a full 10-minute warmup period for the HP 5517B.
• Warmup completion is indicated by the READY LED on the HP 5517B rear panel.
• If warmup is not complete after 10 minutes, a failure may be indicated.
• If the READY indication at the laser head is not convenient to use because of the mounting scheme,
try the alternate monitoring suggestions that follow:
3-13. HP 10740A Coupler Based Systems - Manual Monitoring
• The REFerence and MEASurement signals terminate at either the HP 10760A Counter Card or the HP
10764C Fast Pulse Converter Card.
• Each of these cards includes an LED to monitor the presence of the REFerence and MEASurement signals.
WARMUP
PREHEAT
<-3-6 Min** h>
ON
ON
OFF
ON
±15V Applied to (Begin 100
sec
OPERATING MODES*
LOCKING
HEATER
QUALIFIED
<- 100 sec —>
<r- 50 sec ->
ON ON
ON ON
FLASHING FLASHING
(-2 Hz Rate) (-2 Hz Rate)
ON ON
Laser Controlled by Monitoring
Cavity
Power of Two Laser Frequency
Length
Now Components.
OPTICAL
LOCKED
ON
ON
ON
ON
Reference
Signal
Present,
Laser Now
Ready For
use.