4.5 Commands
4 – 29
4.5.8
Laser trip-off commands
Laser Trip-o
ff
on Current Limit
AILM(?)
{
z
}
Set (query) the laser to trip o
ff
upon current limit
{
to
z
=
(
NO 0
,
YES
1
)
}
.
Typically, this trip condition is left disabled by the user, since the
hardware current limit prevents the LD current from ever exceeding
the limit. If the user wants the LDC500 to automatically turn o
ff
the laser current if the laser current reaches the limit current, set
AILM
YES
.
Front panel:
LD :/@ABB
( 48
.
AILM?
Example:
0
Laser Trip-o
ff
on Photodiode (CP)
APLP(?)
{
z
}
Set (query) the laser to trip o
ff
in CP mode upon monitor photodiode
limit
{
to
z
=
(
NO 0
,
YES 1
)
}
.
This condition applies regardless of the
PDMW
setting, but only for
CP control mode. If the measured photodiode current (or optical
power) exceeds the corresponding limit,
APLP
YES
causes the laser
current source to shut down.
Note that this trip is implemented in firmware, and can only respond
after several hundred ms; if a fast overload occurs (for instance, due
to the analog modulation input),
APLP
cannot assure safe shutdown.
The user should always rely on voltage limiting (
SVLM
) and current
limiting (
SILM
) of the laser diode itself to assure safe device opera-
tion.
Front panel:
LD :/@ABB
48
.
APLP NO
Example:
Laser Trip-o
ff
on Photodiode (CC)
APLC(?)
{
z
}
Set (query) the laser to trip o
ff
in CC mode upon monitor photodiode
limit
{
to
z
=
(
NO 0
,
YES 1
)
}
.
This condition applies regardless of the
PDMW
setting, whether
RESP
is zero or non-zero, but only for CC control mode. If the
measured photodiode current (or optical power) exceeds the corre-
LDC500 Series Laser Diode Controllers
