Grafidy 3 utilizes Grafidy PSD (pulse sequence) and Grafidy
coil fixture, and has an improved user interface to allow more flexibility
and ease of use. Grafidy 3 will adjust and compensate for short, long
and very long time constants eddy currents, both linear and B0 terms.
It is expected that the FE will start the calibration process by
running Grafidy 3 in Auto Mode and then switch to Manual Mode only
if Grafidy 3 cannot bring a term into specification. This should
not often have to be done.
Refer to Table 1 for the suggested Grafidy 3 flow.
Table 1. Grafidy 3 Flow
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Always perform L-Coil Calibration before
starting either DC Offset Adjustment or Grafidy 3 Procedure.
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From the Calibration menu, select L-Coil
Calibration.
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Click on the selection to start the
tool. The calibration runs automatically.
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Always perform DC Offset Adjustment before starting Grafidy
3.
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Configure the system to run Grafidy 3.
Things that will be accomplished here are:
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Set up the standard two-coil Grafidy
kit. The 6-coil Grafidy fixture is not supported.
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Place a rotary attenuator set for 20dB
of attenuation between exciter output and RFI.
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Manual Prescan and get “enough
signal” to make sure the setup is good and the coils are good.
Then Auto Prescan.
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Perform the Auto Grafidy 3 Procedure.
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Start Grafidy3 tool. Select components
that are going to be calibrated and zero out their calibration values.
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Auto Mode is the mode from which Grafidy3
should normally be run. One coil axis is run at a time. Make sure
the physical coil axis and the axis selected on the tool’s user
interface are the same, and then scan.
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Perform Manual Mode if auto mode does not make
all components under spec (still in “red” in User Interface’s
result area/table), go to manual mode to do “touch up.”
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Additional information can be found for GE Service Pull-Down and Aborting/Exiting the Grafidy 3 tool.
