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Vescent Photonics
D2 Series Product Manual
1.4.
Turning on the Laser Diode
In compliance with FDA requirements for a Class 3B laser, the Laser Controller has two safety interlocks.
If either interlock is tripped, the laser will turn off and stay off until the interlocks are reset AND the laser
switch is switched from the “off / reset” position to the “on” position. Additionally, if the Laser Controller
loses power, the laser diode will remain off when power is restored.
To turn on the laser diode, follow these instructions:
1) Flip the Laser switch into “off/reset” position
2) Insert the key into the keyhole and rotate the key 90 degrees (keyhole located on back panel)
3) Place grounding BNC terminator on “Remote Interlock” BNC (located on back panel)
4) Flip the Laser switch into the “on” position. The green light above the switch should turn on and
after a 5 second delay, the laser will turn on.
1.5.
Tuning the Temperature Controller
If you purchased the Laser Controller with a Laser Module, then the Laser Controller is properly tuned
for the Laser Module's thermal load and you can skip this section. This section will describe the basic
theory about tuning the temperature servo response and provide step-by-step instructions for tuning the
servo response to your thermal load.
To get good temperature stability, the temperature servo response needs to be tuned to match the thermal
load. Access to tuning the temperature response is provided on the right side panel of the Laser Controller
and requires removing that side panel to access the controls. The Laser Controller provides two
independent temperature controllers that are nominally identical. However, stage 2 has front panel
adjustment of the temperature set-point, while the stage 1 temperature set-point is a side-panel
adjustment. Additionally, the front panel TEMP SERVO INPUT adjusts the stage 2 set-point while stage
1 does not have an equivalent function. Stage 2 is accessed in the middle of the side-panel, while stage 1
is near the back of the side panel. Typically, stage 2 is used to control the laser temperature and stage 1 is
used to control the temperature surrounding stage 2. In this way temperature gradients between the laser
diode and the thermistor measuring the laser temperature are stabilized and temperature changes caused
by room temperature drift is greatly reduced.
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