Pulnix TM-7EX Specifications download pdf (Page 6)

The 12-pin connector provides connections for power

(+12V DC) and composite video. If the camera model is a

RGB camera such as the TMC-74 it will provide a sepa-

rate line for each video color (RGB). The 12-pin connec-

tor is also where the external sync input is located.

The BNC connector is used for composite video output.

The 6 pin connector is for auto iris or shutter control. This

six pin connector is used to connect to a thumb wheel

switch to set variable shutter speeds (variable shutter is

on the newer lines of video cameras). If an auto iris lens

is required, then this six pin connector is used to control

the auto iris lens.

One final note on connectors. Always consult a data

sheet for connector pinout information because there may

be a subtle difference in the way the connector is wired

from model to model.

A typical way to operate a PULNiX video camera would

be to use a PD12P desk-top power supply and connecting

it to the 12-pin connector on the camera, and take the

video out from the BNC connector to a monitor. Another

common method is to use our standard 12P-02 cable (12-

pin female connector on one end and 12 flying leads on

the opposite end) and connect it to the camera on one

end and wire the opposite end to a power supply (yellow

wire +12V DC and the grey wire 0V DC). The video out-

put is now available both on the flying leads (video red

coax and ground is red shield) or by using the BNC con-

nection. This method also allows for connections for

external sync input and other special signals through the

flying lead end of the cable.

Internal Features

Most of PULNiX's camera series provide certain functions

that enhance the functionality of a camera to meet a wide

range of applications. Some of the common features are

as follows:

Shuttering

For you camera buffs, this may be nothing new to you, but

for the newcomer here is the story behind shuttering.

Typically when an object is moving at a fast pace and you

take a picture of that object, you will notice that the image

is somewhat blurred. The reason for this is that when the

snapshot was taken, the shutter inside the camera opens

to capture an image over a period of time (known as

exposure time). During this time the object is moving

across the image plane of the camera and the end result

is a blurred image. To compensate for this problem we

need to shorten the time the shutter stays open. This will

allow the object to be exposed to the camera's image

plane for a short time period, thus freezing the object and

eliminating the blur. On a 35mm, camera shuttering is

done by mechanical means, but on CCD video cameras

it's done by electrical means.

On our newer line of CCD cameras, shuttering is done by

reducing the amount of time that each pixel captures

exposed light during each field. The shorter the time the

faster the shutter speed.

Many machine vision applications require shuttering

because typically during an inspection process the object

is moving. When shuttering at higher speeds, higher

intensity lighting may be required. Remember that high

shutter speeds translate into shorter exposure times

which means less light that the pixels are exposed to.

One drawback to shuttering a CCD video camera is that

the resolution is cut down to one field. To solve this prob-

lem, the best thing would be to use strobe lighting instead

of shuttering. In this way, a full frame of resolution is

achieved.

Integration

Long term integration is the opposite of shuttering.

Integration refers to the time that the pixels are accumu-

lating a charge (light). Long term integration is defined as

an exposure time longer than one field. Applications that

involve long term integration usually are in a very dark

environment. To compensate for this situation, we

expose the pixels longer than one field to capture as

much of light as possible. The limiting factor in this type

of application is usually the noise (thermal) that is accom-

panied with long term integration. The longer the integra-

tion time the more noise present. To help this noise prob-

lem we have made peltier cooling available to help keep

the thermal noise down by cooling the imager. The cam-

eras that have this feature require an external signal to

control the integration. Also, to capture the exposed

image, it is necessary to use a field or frame grabber to

store (freeze) the image. PULNiX has a field grabber

(VF-400X) for this purpose.

Asynchronous Reset

The asynchronous reset capability allows the camera to

reset the internal vertical drive (sync) to start a scan

again. This feature is used when an application requires

a camera to scan at a specific time. Machine vision usu-

ally requires a camera to capture an image of an object

on the fly at a specific time and place to guarantee that

the image will be in the center of the FOV (field of view).

A scenario would be that a box is flying down a conveyor

and a camera is suppose to capture a bar code image off

the side of a box to verify the quality of the bar code. Now

the box is positioned next to the camera and a sensor is

triggered to signal the camera to start a new scan so that

the bar code is in the total FOV. This will allow the image

processing side (computer) of the application to capture

the image and perform the necessary task of making a

decision (Go/ No/Go) to accept or reject this bar code

image based on what the camera has seen. Think what

would happen if the camera was free running when the

box was in the FOV. Probably what would happen is the

camera would scan and only capture a portion of the bar

code, thus the image processor would reject that box.

Note that in an application like this, shuttering would be

used in conjunction with the asynchronous reset. One of

our newest cameras, the TM-720, is a perfect fit for this

application. It has both the shuttering and async features.

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Pulnix TM-7EX Specifications Page 6

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