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Example of drive circuit for Vinit1 input circuit
75
Ω
6
Vinit1 IN
VC C
3.3V
4.7k
47p
3.3V
10k
100
Ω
NORMAL
INVERTED
3.9 ZD
* The Vinit signal should not include unnecessary
noise components such as chattering.
●
Polarity reversal of Vinit2 input
The input polarity of the trigger signal (Vinit2) to be applied via CC1 of Camera Link can be inverted.
Some capture boards may have the polarity of the trigger signal input from CC1 that is fixed to positive logic (L level at
normal/H level at active), which is not compatible with the trigger signal of negative logic input (factory preset polarity
of this equipment). In this case, the input polarity of the trigger signal (Vinit2) via CC1 can be inverted to change from
negative to positive logic by the setting of the camera.
→
Refer to “(6-3) How to set operation mode” for the specific setting method.
(Note) The setting of the polarity reversal is valid only for Vinit2. The input polarity of Vinit1 is always negative logic
regardless of this setting.
(4-3) Other input/output circuit
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Strobe signal output circuit
The internal output circuit is shown in the
right figure.
(4-4) Strobe signal in continuous shutter mode
Although conventional cameras output the strobe signal (STRB) only in the asynchronous shutter mode, this equipment is
capable of outputting the strobe signal even in the continuous shutter mode by changing the settings.
The default setting is OFF (no strobe signal in continuous shutter mode). This setting can be changed on the configuration
menu (Operation Mode Setting Group C) or by way of rewriting the configuration register with serial communication
commands.
[Explanation] Use of strobe signal in continuous shutter mode
In the continuous shutter mode, only the incoming light for the time matching the exposure time of the camera is valid.
Accordingly, when a lighting unit is used in the continuous lighting mode, the lighting in any time other than this exposure time
period would be wasted.
Since this equipment is capable of outputting strobe signal (STRB) even in the continuous shutter mode, this output is used as a
trigger to control a LED light or other lighting units that can be turned on or off, which helps eliminating the lighting during the
useless lighting time.
The following benefits are derived from this type of lighting control:
●
The consumption of the power to a light can be saved by way of lighting only during the valid time for exposure.
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The occurrence of smear is reduced because no light enters any time other than the exposure time periods.
(Note) When the strobe signal is used in the continuous shutter mode to make ON/OFF control on a lighting source unit,
the following must be taken into consideration:
Wherever possible, use a strobe lighting unit or others that are equipped with a power source separated from that
of the camera (electrically isolated power source) and a trigger input terminal (photo coupler input, etc.). If a
lighting unit that shares a power source or a ground circuit with the camera is turned on or off by the strobe signal,
the image output from the camera may have noise due to the influence of the fluctuation of the power supply
voltage or change in the electric potential that occurs at the ON/OFF timing.
Even when the insulation aforementioned is applied, the electromagnetic induction may lead to the occurrence of
noise on the image signal if the electric current of the lighting unit to be control is large. In this case, a measure
must be introduced to reduce electromagnetic induction noise arising from the lighting unit.
74AC04 or
others
Inside of camera
TC74LVX14
(or equivalent)
To internal circuit
Setting of Vinit2 polarity
CC1 (Vinit2) input
Camera
connector
VCC is +5V or +3V
[Example of user circuit]
+5V
100
6.8V.ZD
Strobe signal: Pin 5
of camera connector
From internal
circuit
74VHCT04A
(or equivalent)
Shutter exposure time
Continuous lighting
STRB signal
Exposure
Exposure
Valid
Useless lighting time
Valid
Useless lighting time
