K11208a;9/36
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●
Example of external sync input circuit and drive circuit
Camera
c onnector
Inside the c amera
To internal circuit
１０ Ｋ
Ｔ ｒ
１ ０Ｋ
４ ． ７ Ｋ
3.3V
3.3 V
22µ F
２ ２ ０
O
１ ００ｐＦ
７ ５Ω
Example of user circ uit
74AC04 or
others
ＶＣＣ
Vccis
+
5V or
+
3V
※
The Vi nt si gnal should not include unnec essary
nois e components s uc h as chattering.
Ext-VD
7
Ext- HD
9
(4-4) Other input/output circuit
●
Strobe signal output circuit
The internal output circuit is shown in the
right figure.
(4-5) 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 3) 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.
●
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.
(4-6)
Test pattern display function
When initially connecting this camera to an image capture board, the
use of the test pattern display function of the equipment makes it easier
to confirm that the output timing of the camera and the details of the
signal connection match the particulars of the capture board.
When the test pattern function is set to be ON, the imager device
outputs not pictures but the test pattern as shown on the right.
As for this pattern, a numerical value of 4 is simply added in an
incremental manner for every horizontal pixel, and a saw-tooth profile is
shown in the range from the numerical value of 0 to 1023.
(Lower part of the right figure)
+5V
100
6.8V.ZD
Strobe signal: Pin 11 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
0
1023
