Sutter Instrument Lambda 10-3, Operation Manual

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LAMBDA 10-3 OPERATION MANUAL – REV. 3.03 (20110829)
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Figure 1-8. SmartShutter timing.
The timing of a SmartShutter is shown in the figure above. The bottom trace is a TTL signal,
the middle trace is a 25 mm SmartShutter, and the upper trace is a 35 mm SmartShutter.
Operation is slower in the ND (Neutral Density) and SOFT modes. In the SOFT mode, the
SmartShutter has a typical time to open of 60 msec. from the point a complete command or
TTL signal is received. The time to close is also 60 msec. This is true for both the 25 mm and
the 35 mm versions. In the ND mode, the time to open and the time to close will depend on
the number of steps selected. For a complete opening of 144 steps, the time to open and the
time to close will each be about 38 msec. The time required will be approximately
proportional to the number of steps, or about 2.6 msec per 10 steps.
1.4.3.3 Repetition Rates and Duty Cycle
Operation does not require over-driving the motor windings, so the motor windings are not
damaged by frequent opening and closing over long time periods. 25 mm (one inch) versions
can usually operate well at up to 20 Hz. 35 mm versions can usually operate well at up to 15
Hz. These shutters may be operated at higher rates up to 40 Hz, but there will normally be
specific frequencies in the higher ranges that will produce errors in motion of the shutter
blade. This is the result of resonances in the mechanical and electrical systems.
If the duty cycle is substantially different from 50%, errors in movement may occur at lower
frequencies. At 40 Hz, the cycle time is 25 msec., with 12.5 msec. between open and close