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4.5 Instrument settings
4.5.1 PILOT LASER Menu
The Laser Diode Controller can drive a pilot laser up to 300mA. Before you enable, make sure that
your Laser Diode was purchased with the appropriate pilot laser, see Delivery Note. This source
deliver constant voltage (+5,0V) for a build in pilot laser (with integrated small driver). Do not drive a
laser diode on this source directly.
Pilot Laser
Change the pilot laser setting between ON and OFF with the Rotary knob. Confirm the value with the
Enter key.
Power
The pilot laser power can be reduced by a PWM (pulse width modulation) of its supply voltage. It can
be set to values between 1% and 100%. Confirm the selection with the Enter key. The desired value
is stored permanently in a non-volatile memory, even when the instrument is switched off.
4.5.2 CALIBRATION Menu
Calibrations Points
Because the laser diode current and its optical output power are approximately linear to each other,
it is possible to calculate the optical power from the current if the user set two measured pairs of laser
current / optical power.
E.g. the user set current to 20A and measured 30W optical power by a power meter. I1=20A,
P1=30W.
Then he set current to 30A and measured 55W optical power. I2=30A, P2=55W.
Note: The deviations from the correct value can increase with distance from the measured value.
Confirm the selection with the Enter key. The desired value is stored permanently in a non-volatile
memory, even when the instrument is switched off.
Power Monitor
If the laser diode is provided with a power monitor (photo diode), the power monitor voltage will be
shown. So, the calibrating can be made without a power meter.
E.g. the user increases laser current up to the power monitor voltage is 1,2V. From the laser diode
data sheet the user read 1,2V = 55W optical power. The actual laser current is 30A. I=30A, P=55W.
4.5.3 CONFIG Menu
The config menu appears the laser diode driver and cooler driver configuration.
4.5.4 Interlock
The Laser Diode Controller is equipped with an interlock feature. The interlock is realized with a loop
which has to be provided via the interlock connector, see section Connector pin-out.
The interlock loop must be realized either with the provided dummy connector (permanent closed
loop) or a peripheral device. It is prior to the Laser key at the front panel. The laser diode can only be
turned on with pressing the Laser key at the front panel if the interlock loop is closed. If the interlock
loop is opened while the laser diode is on, the laser diode is immediately turned off and a error
message appears on the display. The laser diode can only be turned on again by closing the interlock
loop.
Summary of Contents for ldc1000
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