Examples of luminaire calculation

Problem

There is a illuminator. It is necessary to create its model in VideoCAD.

Sensitivity of cameras is modeled only in VideoCAD Professional

Solution

To create new illuminator click the Illuminator button on the Tool bar.

To edit existing illuminator double click on its icon on the layout.

To edit just created illuminator click the Edit button on the Current construction parameter panel.

To open the Illuminator calculation box click the Illuminator calculation button on the Current construction parameter panel.

The calculation may be approximate or more precise, depending on that parameters are known.

1. Approximate calculation of visible light luminaire

2. More precise calculation of visible light luminaire

3. Approximate calculation of IR illuminator

4. More precise calculation of IR illuminator

1. Approximate calculation of visible light luminaire

It is known:

•	Lamp type, power consumption of one lamp and number of the lamps;

•	Angle of radiation (degree).

Order of calculation:

1. Choose lamp type in the Lamp type combo box.

2. Enter power consumption of one lamp in the Lamp power (watt) combo box.

3. Choose number of lamps in the luminaire in the Lamp quantity combo box.

4. Choose Efficiency factor=0.6 in the Efficiency factor combo box.

For projectors with angle of radiation less than 50 degrees select efficiency factor=0.3.

If efficiency factor is known from specification, this known factor should be entered.

If a lamp without reflector is being modeled, 0.8 should be entered in the efficiency factor box and the Omnidirectional light source panel should be selected. After that jump to the step 7.

5. Enter Angle of radiation.

6. Enter 0.5 to the Concentration combo box.

At concentration=0.5 light intensity on the edges of the light cone makes a half of axial light intensity.

7. Click OK.

2. More precise calculation of visible light luminaire

It is known:

•	Lamp type, total light flux of one lamp and number of the lamps;

•	Light intensity curve with lamp with full light flux of 1000 lumen.

You can find the Total light flux of lamp in the lamp specification. You can find the the Light intensity curves with lamp with full light flux of 1000 lumen in the luminaire specification.

Order of calculation:

1. Choose Lamp type in the Lamp type combo box.

2. Enter Full light flux of one lamp to the Light flux emitted by lamp (lm) combo box.

3. Choose number of lamps in the luminaire in the Lamp quantity combo box.

4. Using the Light intensity curve with lamp with full light flux of 1000 lumen determine the angle of radiation (degree) and the axial light intensity (candle).

5. Enter Angle of radiation to the Angle of radiation combo box.

6. By choosing concentration value in the Concentration box or by moving grips when editing illuminator (holding Ctrl), try to obtain light intensity curve, close to light intensity curve from the specification.

Light intensity distribution curve is displayed by orange line during drawing or editing illuminator.

Light intensity distribution curve represents relative light intensity distribution. The curve does not depend on absolute values.

7. Recalculate the axial light intensity of the luminaire in proportion to the total light flux of the lamps.

For example: The total light flux of all lamps is F=3000 lumen. In this case an axial light intensity value obtained from the light intensity curves (with the lamp of 1000 lumen) has to be multiplied by 3.

8. By choosing Efficiency factor in the Efficiency factor combo box, obtain the axial light intensity in the Axial light intensity (cd) box which is equal to the axial light intensity calculated in step 7.

9. Click OK.

3. Approximate calculation of IR illuminator

It is known:

•	Consumed electrical power and wavelength of radiation maximum;

•	Angle of radiation.

Order of calculation:

1. Choose LED of known wavelength in the Lamp type combo box.

2. Choose consumed electrical power of the IR illuminator in the Lamp power (watt) combo box.

Consumed power of the illuminator is equal to the product of supply voltage (volt) multiplied by consumed current (ampere). These parameters are given in the illuminator's specification.

3. Choose '1' in the LED quantity combo box.

4. Choose in the Efficiency factor combo box:

Efficiency factor=0.3 for narrow angle illuminator (angle of radiation is 20-50 degrees);

Efficiency factor=0.5 for wide angle illuminator (angle of radiation is 60-120 degrees).

For hot climate select efficiency factor=0.2-0.3.

5. Enter Angle of radiation to the Angle of radiation combo box..

6. Enter 0.5 to the Concentration combo box.

At concentration=0.5 light intensity on the edges of the light cone makes a half of axial light intensity.

7. Click OK.

4. More precise calculation of IR illuminator

It is known:

•	Wavelength and number of LEDs in the illuminator;

•	Axial radiant intensity (watt/steradian) of one LED and angle of radiation of one LED (degree);

•	Radiant intensity curve in dependence of angle for one LED (not obligatory).

Wavelength, axial radiant intensity and radiant intensity curves could be found in the LED specification. For this it is necessary to know LED model.

Radiant intensity in operating mode is changed in direct proportion to current through the LED.

Order of calculation:

1. Choose LED of known wavelength in the Lamp type combo box.

2. Choose number of LEDs in the illuminator in the LED quantity combo box.

3. Enter Angle of radiation to the Angle of radiation combo box.

4. By choosing concentration in the Concentration box or by moving grips when editing illuminator (holding Ctrl), try to obtain the radiant intensity curve, close to radiant intensity curve of one LED.

Light intensity distribution curve is displayed by orange line during drawing or editing illuminator.

The Light intensity distribution curve represents relative light intensity distribution. The curve does not depend on absolute values.

In case of the Light intensity distribution curve is not available, - enter 0.5 to the Concentration combo box.

5. Choose 0.9 in the Efficiency factor combo box (temporarily).

6. By choosing radiant power in the Radiant power (watt), obtain the axial radiant intensity in the Axial radiant intensity (watt/Sr) box which is equal to the product of axial radiant intensity of one LED multiplied by the number of LEDs in the illuminator.

7. Choose 0.5 in the Efficiency factor combo box for considering power lost in internal circuits.

For hot climate and for illuminators which are get hot select efficiency factor=0.3.

8. Click OK.

The created illuminator model with specified parameters will be the calculation result.

For information in the box the following values are displayed:

•	Axial light intensity;

•	Illumination produced by the illuminator at specified distance an axis of radiation.

Using a luxmeter you can check illumination value on specified distance from the real illuminator, then choose parameters to achieve full identity of the model and the real illuminator.

You can change location of created illuminator model in horizontal projection by moving and rotating similarly to other constructions.

You can specify installation height, vertical inclination angle, dispersion, switch illuminator ON/ OFF on the Current construction parameter panel. Illuminators can be copied.

To allow for lamp aging, supply voltage deviation, as well as luminaire dirt depreciation in operation it is necessary to set Maintenance factor of illuminators on the Illuninationtab of the Options box according to CIE 97.

External link: "The principles of CCTV design in VideoCAD. Part 4. Illumination and camera sensitivity in CCTV"(*.pdf) .

Help URL: http://www.cctvcad.com/videocad_help/index.html?prim14_lampcalcexample.htm

Examples of luminaire calculation						PRIM14_LampCalcExample Dear CCTVCAD Software,
Examples of luminaire calculation