Shutter Frequency of Operation
The repeat exposure specification as listed in this manual is specified at 35ms. This is an
optimum value to ensure enough pulse energy to open any
UNIBLITZ
shutter. However the
VMM-T1
or
VMM-D1
is capable of operating each Vincent shutter to its maximum frequency
with a slight sacrifice in shutter opening speed. This is due to the drive circuit, which allows
the pulse voltage to drop with an increase in frequency to compensate for the heat that is
developed in the shutter coil. (See graphs Figure #7 and 8) Please contact the factory for
specific information concerning shutter modifications and/or drive modifications that may be
necessary for operating shutters at their maximum frequency. Please note also that fuse
blowing problems, specifically shutter fuses, may be due to high frequency operation without
proper fuse selection. Due to the large number of different frequencies and duty cycles that the
shutter is used with, please contact the factory for further details regarding specific fuse
selection.
Trigger Cautions and Trouble Shooting Tips
1. The
VMM-T1
or
VMM-D1
system's capability can be greatly enhanced by external control as
described previously, however, extreme care must be taken to ensure that high voltages (see
SPECIFICATIONS) are not inadvertently switched into external control inputs. Also, note that
large negative voltages can cause irreparable damage to the unit's internal circuitry. Exercise
extreme caution.
2. As noted previously, a visual inspection of a fuse is usually
NOT
an adequate test to determine
if a fuse failure has occurred. Use a DMM (Digital Multi-Meter) or equivalent test device to
determine fuse continuity.
3. Particular shutter units respond to different minimum pulse widths. For example, a standard
VS25 shutter (with Teflon shutter blades) has a minimum exposure pulse of 6ms, if the timing
or pulse width presented is set for an exposure pulse width less than 6ms, the shutter may not
open fully. If the unit still does not operate properly, when using the proper pulse width, please
notify Vincent Associates immediately.
4. If you are
using a Vincent 910RS or 910RSDC RS-232 interface cable, please note, a
standard RS-232 cable will
work with these controls. You must use a “
NULL MODEM
”
type interface cable.
not
not
5. When you receive your controller and shutter, the shutter may be shipped with a small circular
white plastic protective ring around the shutter’s male connector contacts. This ring protects
the male connector’s contacts during shipping. This ring is held on by friction and must be
removed prior to attaching the female end of the 710C cable to the shutter. This ring can be
removed by gently pulling up off the top of the connector. Tools are not required to remove
this ring.
VMM-D1 & VMM-T1 User Manual
32
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