GE Healthcare
Senographe DS
Revision 1
Service Information and Procedures Class A 2385072-16-8EN
Job Card CAL A048 - Calibration of Compression Force Sensor
Page no. 1709
Chapter 9
JC-CAL-A-048.fm
Job Card CAL A048 - Calibration of Compression Force Sensor
Chapter 9
1
SUPPLIES
None
2
TOOLS
•
Calibrated force detector capable of measuring compression force between the compression paddle
and the image receptor: required accuracy ±0.5 daN. The
Mammography compression scale with
is recommended.
•
3
REQUIRED EFFORT
Personnel: 1 Field Engineer
Time: 20 minutes
4
SAFETY PRECAUTIONS
None
5
PREREQUISITES
None
6
COMPRESSION FORCE CALIBRATION
6-1
Principle
•
The compression force sensor is factory calibrated. However, if parts have been replaced or dis-
turbed which affect the software or hardware settings, calibration must be carried out.
•
The calibration establishes a suitable transfer function relating the signal from the internal force sen-
sor to the true force. This is done by comparing the force reported by the internal sensor with the
force measured externally by a calibrated force detector at several points over the working range.
The system software can then calculate compression forces to an accuracy of 1 daN.
Note:
If the Paddle Holder Assembly, Force Sensor or Paddle Holder Board has been replaced it is pos-
sible that system reports
122/021H03 COMPRESSION CONTROL ERROR
on the Gantry LCD
Readout when Gantry is powered on.
This error can occur when the old calibration information stored in the system differs too much from
the parts that have been installed causing system to think that compression force is out of allowed
range.
When this situation happens it is not possible to enter calibration mode. If this happens first try add-
ing some compresion force with the manual compression knobs and reboot the Gantry. Try 10, 20
and 30 daN and use calibrated force sensor to measure it. If the system does not boot with any of
these settings remove compression by manual knobs and add 10daN negative force by adding ap-
proximately a10 kg mass on top of the Paddle.
When the system boots, enter the calibration mode and when the Gantry LCD Readout requests
calibration for 0 daN force remove the compression or weight on paddle and continue calibration
normally.