Справочник Пользователя для Pelco C3427M-D (2/09)

C3427M-D (2/09)

19

VERTICAL PHASE ADJUSTMENT
Use this procedure for 24 VAC operation only.

When using more than one camera power supply, a brief vertical roll may occur on the monitor when 
switching from one camera to another.

To eliminate vertical roll, reverse the 24 VAC connections on one camera. If both cameras are connected to 
the same transformer, this should solve the problem. If the problem persists, adjust the phase control by 
synchronizing, or line-locking, the cameras to one another. 

NOTE: When adjusting vertical phase, line sync (SW4-3) must be set to OFF for AC line lock.

You may need two people when synchronizing the cameras: one at the camera, the other at the monitor to 
observe the vertical roll and the effect of any camera adjustments.

To synchronize the cameras:

1. Choose a reference camera to which all other cameras will be phased.

2. Select the camera to synchronize. Use buttons SW1 and SW2 to synchronize the camera to the 

reference camera (refer to Figure 10 on page 17). SW1 increases vertical phase; SW2 decreases 
vertical phase.

3. Each time an adjustment is made, switch back and forth between the camera you are adjusting and 

the reference camera. Repeat this process as many times as necessary until the roll between the 
cameras is no longer noticeable.

4. Adjust the phase of all other cameras by repeating steps 2 through 3. Always adjust to the reference 

camera selected in step 1.

NOTE: The preferred method for camera phase adjustment is to use a dual trace oscilloscope to align the 
vertical sync pulses of the reference camera to the selected camera(s).

If small white or color spots appear in the video image, one or more pixels on the camera imager may be 
defective. (This condition is common for both CCD and CMOS imagers.)

DN and CH Series cameras with auto iris lenses automatically detect and correct defective pixels during 
startup. Video turns on, then off, and then on again. If white or color spots still appear, you can correct the 
defective pixels manually.

CH Series cameras with fixed iris lenses do not automatically detect and correct defective pixels. You can 
correct the defective pixels manually.

To manually correct defective pixels (refer to Figure 10 on page 17):

1. Cover the lens completely. Make sure no light can enter the lens.

NOTE: The mechanical iris lens aperture does not completely block the light.

2. Press and hold button SW3 for one second. The camera will find and correct defective pixels; 

however, any defective pixels that cannot be completely corrected may still appear.

3. Release button SW3.

4. Uncover the lens for normal camera operation.