3.5 Constant power mode (CONST P)
LDC2xx / page 20
After pressing "ON" (L9) the LED "OPEN " (L6) extinguishes and the laser diode
current output can be switched on again by pressing "ON" (L9).
The laser current can be modulated via t
he connector "MOD IN" (R3) (refer to
chapter 3.7).
3.5.1 Changing the "I
PD
" setting range
To guarantee an easy setting of the operati ng point in constant power mode even
with small photodiode currents t he full scale of the adjustment knob (L10) can be set
with potentiometer "PD RANGE" (L24) between 0.6 mA and 2 mA.
Turn the potentiometer "PD RANGE" (L24) comp letely to the left (i.e. full scale = 0.6
mA).
Turn the adjust knob (L10) completely to the left.
Select constant power mode CONST P, connect the laser diode and the photodiode
and switch on the laser current.
Set the desired photodiode current with the knob (L10).
If the desired operating point cannot be reac hed even if the knob (L10) is turned
completely to the right (i.e. I
PD
> 0.6 mA), turn the potent iometer "PD RANGE" (L24)
to the right until the desired setting range has been reached.
NOTE:
Changing the position of the potentiometer "PD RANGE" (L24) changes
the set value in constant power mode. In constant current mode the
potentiometer "PD RANGE" is without function.
