15
ENABLE/DISABLE OUTPUT
CURRENT
On the front panel, the LDD Enable and TC Enable buttons
dictate whether or not output current is enabled.
To enable either the LD or the TC current, push the
corresponding button on the front panel. If output current is
enabled, the LED will be lit (red for laser, blue for temperature
control). There is no time delay before temperature output
current is enabled after pushing the button. By default, there
is a 2 second delay after pushing the LDD Enable button for
current to be output to the laser.
To disable current, press the corresponding Enable button
again. Once the button is pushed, current will immediately
disable, and the LED will become dark.
DISPLAY EXISTING CURRENT
AND VOLTAGE VALUES
Press to access the Dual Monitor Screen.
Values on this screen cannot be changed and
are for information only.
Figure 21. Dual Monitor Screen
LD Current, LD Voltage, PD Power or PD Current (see
Note below), and PD Bias Status are the laser parameters
displayed. Temperature control parameters displayed
include Actual Temperature, Sensor Voltage, TE Current
(appropriately signed), and TE Voltage. If the temperature is
within the defined tolerance, the target icon will be visible.
NOTE: PD Current is displayed here if the PD Transfer
Function (specified on the Photodiode Screen) is zero (OFF).
PD Power is displayed here if the PD Transfer Function is
nonzero.
DISABLE CONDITIONS
If certain operational parameters are exceeded or improperly
configured, output current to the LD and/or TC will be disabled.
Using the
LASer:ENABle:OUTOFF
remote command, the
instrument can be configured to disable laser current if certain
temperature conditions are not met. See
• Load Open/Short:
»
The instrument will detect if there are open or shorted
conditions across either the LD or the TC connections.
The TC portion of the instrument will continue to
operate if the laser portion malfunctions. Whether
or not the LD portion of the instrument continues to
operate if the TC portion malfunctions can be set by
the user via remote commands.
• Over- or Under-Temperature:
»
If the temperature limits that are set by the user
are exceeded (either high or low), current to the
thermoelectric will be disabled. Current to the laser
can be disabled via remote commands.
• Over- or Under-Voltage:
»
The LDTC LAB monitors the power supply voltages
and triggers an error and shuts off the output if the
internal power supplies are out of a pre-determined
range.
