Uniblitz VMM-T1, User Manual

Page: 30 / 43

VMM-T1 User Manual 30
Shutter Frequency of Operation
The repeat exposure specification as listed in this manual is specified at 35 ms. This is an optimum
value to ensure enough pulse energy to open any
UNIBLITZ
shutter. However, the VMM-T1 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 6 and 7.
Contact the factory for specific information concerning shutter and/or drive modifications that may be
necessary for operating shutters at their maximum frequency.
Please note 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 in which the shutter is used please contact the factory for further details regarding specific fuse
selection.
Trigger Cautions and Trouble Shooting Tips
The VMM-T1 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 .
Visual inspection of a fuse is 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.
Particular shutter units respond to different minimum pulse widths. For example, a standard VS25
shutter with Teflon coated shutter blades has a minimum exposure pulse of 6 msec. If the timing or
pulse width is set for an exposure pulse width less than 6 msec the shutter may not open fully. If the
unit still does not operate properly, when using the proper pulse width, please contact Vincent
Associates immediately.
Please note that if a Vincent Model 910RS RS-232C interface cable is not being used, a standard RS-
232C cable will not work with these controls. A “ NULL MODEM ” type interface cable must be used
in this situation.
When operating shutters with apertures larger than 25 mm, please be sure that the FUNCTION slide
switch “E” is set to the upper position. Failure to make this change may result in incomplete shutter
opening and causing immediate shutter close resulting in probable loss of capture.
When operating shutters with a 25 mm aperture or smaller, please be sure that the FUNCTION slide
switch “E” is set to the lower position. Failure to observe this setting is likely to cause damage to the
shutter, thereby voiding the shutter warranty.
The shutter may be shipped with a small circular white plastic protective ring around the male connector
contacts. This ring protects the male connector’s contacts during shipping. It is held on by friction and
must be removed prior to attaching the female end of the Model 710C cable to the shutter. This ring can
be removed by gently pulling up off the top of the connector. No tools are required.