Lambda SRS SR475, Руководство по эксплуатации

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1 – 4 Operation
the laser aperture, and in the closed position the shutter blade fully
covers the aperture.
The process of opening or closing the shutter consists of guiding the
blade along a smooth, pre-determined trajectory between the closed
and open positions. In what follows we will describe this in more
detail. For clarity we will discuss only the case of opening, but the
sequence of events applies equally to closing the shutter.
When the shutter is initially closed and it receives a signal to open,
it begins moving the shutter blade under servo-loop control along
the preprogrammed “opening” trajectory. Once this has begun, the
shutter will guide the blade along the entire trajectory—bringing
the blade to a full stop at the open position—before carrying out
any subsequent instruction to close. In other words, a transition
in progress cannot be reversed or aborted (except by disabling the
motor).
Sample trajectories for opening and closing are illustrated in Fig. 1.2.
For the SR475, each pre-programmed trajectory takes 5 ms to com-
plete when running at full speed. This means that the minimum time
to complete a closed-open-closed full cycle is 10 ms, which gives the
shutter’s maximum rate of 100 Hz. The minimum exposure time be-
tween the midpoint of opening and the midpoint of closing is 5 ms.
For the SR476, each full-speed pre-programmed trajectory takes 4 ms,
and a full cycle takes a minimum of 8 ms. This gives a maximum
rate of 125 Hz and a minimum exposure time of 4 ms. For both mod-
els, when full speed is not needed, there are alternate speed modes
available that use less power and create less vibration; see
§
1.6.
1.1.4 Power-off and standby states
The SR475 and SR476 Laser Shutters do not incorporate return
springs. The shutter blade is in an indeterminate position when-
ever the shutter is powered o
ff
or in the Standby mode.
The shutter is in the Standby mode whenever its
+
4.5 VDC “logic”
power supply is available but the motor is not enabled. In this mode,
the logic power supply provides power for serial communications,
but the motor is turned o
ff
and the shutter blade position is therefore
indeterminate.
The shutter head can be placed into Standby with a remote com-
mand. It also enters Standby mode automatically when certain fault
conditions are detected. These conditions include mechanical failure,
over temperature, and undervoltage on the
+
12 VDC power supply
for the motor. The shutter head may also be put into Standby by
intentionally turning o
ff
the
+
12 VDC power supply. To ensure that
SR475 and SR476 Laser Shutters