THEORY GUIDE Sequence of Operation
10DEC05
TG4825-1
Page
28 of 120
3 The PLATE PRESENT SENSOR S5 detects that a PLATE is fastened and sends a
message of the status to the MSC BOARD A1.
Scanning the SCREEN
1 The MCPU BOARD A2:
• actuates the GALVO
• sends a signal to the MSC BOARD A1 to start the scan, which starts the SLOW
SCAN MOTOR
• sends a signal to the INTERNAL PC that the scan is starting
2 The INTERNAL PC displays a TIMED PROGRESS BAR on the TOUCH SCREEN
MONITOR. This is a graphic display only and not a real-time indication of the status of
the scanning operation.
3 The SLOW SCAN MOTOR rotates, moving the SCREEN at a continual speed through
the field of scan in the slow scan direction.
4 The GALVO BOARD A4 controls the motion of the laser beam across the SCREEN in
the fast scan direction. The SCREEN is scanned one pixel at a time, one line at a time.
See “Scanning the SCREEN - Slow Scan/Fast Scan.”
Note
• The fast scan motion is an almost horizontal trace across the SCREEN, from the back of
the SCREEN toward the front. When it reaches the end of a line, it does a fast retrace to
start another line. During the scanning, the SCREEN is moving down at a controlled
speed to make each fast scan trace one pixel line higher up on the SCREEN than the line
before. The result is that the fast scan is in a slightly diagonal trace across the SCREEN.
• The slow scan runs for a determined number of lines in the vertical direction. A set
number of samplings occur for each line. The number is determined by the size of the
Status Summary: Prepared for Scanning
• PMTs are energized
• SIGNAL CHANNEL is set to 0