Appendix D Calibration (Using Generator Service Tools)
HF Series X-ray Generators - Service Manual Revision W
Quantum Medical Imaging, LLC D-35
6. If using an oscilloscope, observe the small filament current pulse wave-
form for "flatness" (see Figure D-18). If using a mAs meter, observe the
measured mA value. Ideally, the mA value appearing in the Small Fila-
ment Calibration Screen (Step 1.) will match the reading on the mAs
meter within allowable tolerance.
7. Press the Calibrate button.
8. If waveform is acceptable or if mA reading is within tolerance, press the
Confirm button. The calibration value is saved and the system advances
to the Large Filament Offset Calibration setting.
9. If mA is not within tolerance or if waveform is not flat, press the Repeat
button.
10. Increase or decrease the preheat value displayed on the Small Filament
Calibration screen (Step 2.) by adjusting the slide control, or by selecting
the data entry box and typing the value using a keyboard. The value
entered should be to the hundredths decimal place. The preheat value
adjustment range is from +2.00 down to -2.00, with 0.00 equating to no
offset applied to the tube’s default filament curve. To increase mA, raise
the filament offset value; to decrease mA, lower the filament offset value.
Note: An error message appears if the filament
current is set too low, which indicates the fila-
ment offset value for the filament being cali-
brated is set too low or high. If this occurs,
increase or decrease the filament current.
11. Re-take the exposure at same settings and adjust preheat value as nec-
essary. Repeat this step until measured mA is within tolerance, or if
using an oscilloscope, when waveform is sufficiently flat. Press the Con-
firm button to proceed to Large Filament Offset Calibration.
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