MOGlabs DLC202, Руководство пользователя, Страница: 55 / 82

B.3 Locking 45
B.3 Locking
The
MOG
labs controller provides feedback via three channels each
with a complex servo loop function. A few common problems are
addressed here; for more difficult problems,
MOG
labs will be happy
to work with you to find the best possible solution.
B.3.1
SLOW
does not lock
• Try locking with
STACK
only,
DISC
only, or both (see
DIP
switches
1,2
).
It can be very useful to watch the
SLOW
output (via
CHAN A
)
when locking.
• Try locking with
FAST
channel only. If
FAST
locking works
but not
SLOW
, then there is a gain or polarity problem, or a
disconnect on one of the slow actuators (
STACK
,
DISC
).
•
STACK
feedback has wrong polarity. See
DIP
switch
10
.
• Lock signal zero-crossing too far from trigger point.
• Gain too high. Try smaller and smaller gain, but be careful to
ensure that the lock error signal is crossing zero.
• Loop response too fast for actuator. The controller is normally
shipped with slow-channel response gain of 1 (0dB) around
700 Hz. Please contact the factory for instructions on changing
this for slower actuators.
B.3.2
SLOW
locks only briefly
Usually this is because the
STACK
feedback has the wrong polarity.
Again, it can be very useful to watch the
SLOW
output (via
CHAN A
)
when locking. Try flipping
DIP
switch
10
. Ensure the laser frequency
is scanning properly, i.e. that the
STACK
is properly connected and
working.