44
Do not modify coefficients without factory authorization.
o
S4B GAIN – 0,0,0 for standard BNW
⁷
coefficient set.
(In any unique case where a factory-
approved non-standard filter coefficient set is used, recommended values will be supplied.)
o
S3K –Verify standard coefficient set: X kp = 0.1, X k1 = 1.0, X k2 = 1.0; same for Y, Z axes.
o
Select the appropriate System Configuration: MMA for MRI sites, MEA for EMFC sites.
o
Options – If designated in site work order, select configuration-specific options; leave
(ungreyed) box or boxes unchecked if no options required.
(Refer to MACS/D SW/FW
documents for option details.)
o
Important: Verify that the Serial number matches the serial number on the rear panel of the
MXA Controller. Contact factory if not in agreement.
5.3 FIELD COMPENSATION ADJUSTMENT AND VERIFICATION
Push the
DISABLE
pushbutton switch on the MXA controller front panel (FP) and observe that the machine
state goes to
DISABLED-PB
as indicated in the FP display, also indicated by flashing blue
RESET
and solid red
DISABLE
indicator lights.
Press the
RESET
pushbutton switch and observe that system goes through
ACQUIRE
state to
SETUP
state, then to
OPERATE
state.
Confirm monitor probe operation.
5.3.1 Setting the Axis Polarity and Gains (MEA and MRI):
• Test X-axis closed-loop polarity by increasing X Output Gain at 4 dB while observing channel behavior on
the MACS/D MXA controller FP “X” display. Look for a decrease in the interfering signal. If the signal increases,
keep the Output Gain setting at 4 dB, switch the polarity (at right side of Output Gain slider) and observe an
interference decrease of about 20%. If the interference level is low and the difference between the polarities is
not discernible, proceed to the next step.
• Open the “X Drive” display. While observing the “X” FP display, increase the Output Gain slider on the X-axis
until high-frequency oscillation occurs, as evidenced by a sudden jump in the axial display value, which should
occur at a slider setting of 30 dB or more, then back off the slider setting by 4 dB (two slider detent positions)
to achieve the best loop gain setting. During oscillation, the X Drive display should show both large positive and
large negative excursions. If the system instead “rails out” at a lower slider value, and with a constant maximum
positive or negative X Drive value, the loop polarity is incorrect. Reduce the Output Gain to 4 dB or below,
reverse the channel polarity and retry.
• Repeat the above procedure for the Y- and Z-axes, observing the applicable FP displayed value and
graphic chart.
5.3.2 ACR Setup:
5.3.2.1 MEA (Applicable only for large interfering gradients):
• Adjust Gamma values ± for optimum cancellation at Protected Volume (PV) survey probe location, which
may be at a distance from the system sensor probe actual position. Note: ACR adjustments are made in the
displacement axes only.
⁷ Second generation processing filter configuration and coefficient set.