Section 4 - Alignment & Calibration
4-27
entries are not present, or are zero, the motion limits are set to the mechanical limits, as in
the above example.
Type
Y<Enter>
to accept the calibration values or
N<Enter>
to reject them.
Note:
The last calibration scan data is saved in the file
MOTOR_AR.DAT
. You can re analyze
the data–e.g., after editing
hardware.ini
–by typing the command
CALIBRATE
@MOTOR_AR.DAT
at the MOTOR$AR> prompt in SQDRIVER.EXE.
LASER POSITIONING OFFSET ADJUSTMENT
Center the table and arm using Center Table, or utility A/P position feature. Turn on the laser
and set it on the point of a sharp object. At the DOS prompt type SCANSQ -PNOFLAT and
begin a scan. Using the F3 function, realign the arm to the proper position and exit before the
scan begins. Turn on the laser and physically adjust back to the point of the object as follows:
1.
Locate the 3 laser adjustment screws (small Phillips) under the C-arm. Adjust these
screws until the laser cross-hair is on the pointed object.
2.
Run another scan to check your adjustments.
A/D GAIN CONTROL ADJUSTMENT
Before performing the A/D Gain Control Adjustment, check the Hi/Lo Resolution jumper in the
upper left corner of the ADC board (the jumper is in for high resolution).
In order that all QDR 4500 machines have the same input to the A/D converter, regardless of
slight variation in X-ray flux detected, a potentiometer has been installed on the unit’s ADC
board.
All covers, that are normally in the X-ray beam, must be on.
This potentiometer is set
as follows:
1.
With the table all the way down, go to survey program SUSQ located in the MENU
directory.
2.
Set Pulse to 1. ALT-p
3.
Set High gains to 1 for QDR 4500A and SL. Set High gains to 2 for QDR 4500W and C.
4.
Set Low gains to 0 for QDR 4500A and SL. Set Low gains to 1 for QDR 4500W and C.
5.
Set X-ray Mode to 3.
6.
Set Aperture to 11 (this step for QDR 4500A and SL only).
7.
Bring up graphic display. CTRL PGDN
8.
Set to observe Hi Air.
9.
Turn on X-rays and observe the screen. Check that the X-ray level on the display is
between 4.5V and 8.5V. The graph should be approximately even from front to back. If
it is not, it indicates that the source and detector may require alignment. If any part of
the graph is below 4.5V or above 8.5V, it may indicate either bad detector(s), or an
adjustment is required. Note that a “spike” or “absence” may indicate a bad detector.
To Next Page
Loading...
