Newport FSM-300, User Manual

Page: 22 / 42

22 Unpacking the FSM
FSM operation is limited to an envelope of mirror deflection amplitude
versus frequency. For the FSM-300, amplitude is mechanically limited to 26
mrad up to 40 Hz. Above 40 Hz, long-term, continuous operation is limited
by the allowed thermal loading of the drive coils. The latter is approximately
proportional to signal amplitude times frequency squared. This means that
above 40 Hz, the maximum allowed amplitude is inversely proportional to
the square of frequency.
If the coils reach a temperature warning threshold, as measured by thermis-
tors, a yellow warning light labeled CURR comes on; however, the system
continues to operate as before. If the coils reach an upper temperature shut-
off threshold, a red warning light labeled TEMP comes on, and the mirror
reverts to the unpowered state. Upon cooling of the coils, the red light will
go off, and the system will automatically resume normal operation.
If the yellow warning light comes on during normal, continuous operation,
consider decreasing the drive signal frequency and/or amplitude to prevent
overheating of the drive coils and avoid a possible thermal shutdown.