Rockwell Automation 6157 Industrial 20 inch Monitors - Manual (Page 18)

18 Industrial 20" CRT Monitor
Publication 6157-5.1
4. Use the left arrow button to lower the brightness until the dark gray
colors change back to black. This is the optimal brightness setting
given the current lighting conditions
5. Press the Select Mode button until the status LED indicator below
the Contrast icon is lit.
6. Use the left and right arrow buttons to change the value for the
contrast control to achieve the appropriate level of intensity in the
image.
Horizontal and Vertical Size and Position
The monitor is factory preset and normally requires no manual
adjustment for vertical or horizontal alignment. However, four
adjustable size and position controls are provided to permit adjustment if
it should become necessary.
To change size or position:
1. Press the Select Mode button until the status LED indicator below
the appropriate icon is lit.
2. Use the left and right arrow buttons to change the value for the
selected control.
Raster Rotation
A raster rotation control allows for corrections to any display
misalignment which might be present as a result of interaction between
the monitor and an external, low-level uniform magnetic field, such as
the earth’s magnetic field.
All CRT displays are affected by the earth’s magnetic field and by
similar low level uniform fields. Generally, the effects of such a field on
the display vary with the display’s spatial orientation relative to the field
lines. For example, when the unit’s screen is facing west, the effects of
the earth’s field are minimal. When the screen is rotated toward the north
or south, the display can exhibit a small amount of rotation, so that its
top and bottom edges are no longer parallel to the edges of the panel.
Note: This effect is different from the effect of magnetism on the
shadow mask, which takes the form of color impurity and is
corrected by the degaussing system.
Before making any adjustments, display a full screen image and check
for rotation (top or bottom edge of the image out of parallel with the
corresponding edge of the panel).