45 minutes (plus 30 minutes for Agilent wattmeter power up)
5 minutes
Table 2. Tools and test equipment
Item
Quantity
Effectivity
Part number
Manufacturer
12 inch Crescent
Wrench
1
-
-
-
Medium Phillips
Screwdriver
1
-
-
-
Small Flat Head
Screwdriver
1
-
-
-
RF power measurement
kit (use one of the following kits):
1
-
EITHER 5307511-2 or 5307511-3 (Bird wattmeter)
BOTH 5491202 (Agilent wattmeter) and 5491202-2 (dummy load)
-
Digital Multimeter
1
-
46-194427 P284
-
Table 3. Safety
DANGER
FATAL ELECTRIC SHOCK HAZARD!
THE RF AMPLIFIER IS NOT DISABLED.
TO PREVENT FATAL ELECTRIC SHOCK, ENSURE THE RF AMPLIFIER
IS DISABLED WHILE CONFIGURING THE CALIBRATION TOOLS.
Warning
ELECTRICAL/RF BURN HAZARD!
RF BURNS Can Occur AS A RESULT OF DISCONNECTING HELIAX CABLES
WHILE THE SYSTEM IS SCANNING.
PREVENT POSSIBLE RF BURNS WHEN DISCONNECTING HELIAX CABLES
FROM THE RF AMPLIFIER BY VERIFYING THAT THE SYSTEM IS NOT MANUALLY
PRESCANNING OR SCANNING. VERIFY THAT THE SCAN DESKTOP ICON DISPLAYS
THE “IDLE” MESSAGE AND THE RF ENABLE SWITCH IS IN THE
“OFF” POSITION.
CAUTION
Possible equipment damage!
Operating the RF amplifier with an improper load can cause
permanent damage to the amplifier.
Do not operate the RF amplifier with an improper load connected
to its output.
CAUTION
Possible equipment damage!
Hardware and phantoms left in the magnet bore can cause
equipment damage.
Prevent coil and associated switch damage by removing all
phantoms and hardware (such as head coil or surface coil) from the
magnet bore.
CAUTION
Possible equipment damage!
If the wattmeter sensor is connected or disconnected while
the meter is ON, equipment damage can occur.
Do not connect/disconnect the wattmeter sensor while the
meter is ON. Always turn the meter OFF before plugging/unplugging
sensor.
Table 4. Required conditions
Condition
Reference
Effectivity
Before beginning this procedure, confirm that the exciter
has been on for at least 20 minutes.
-
-
When using the Agilent wattmeter,
plug in the wattmeter and turn it on. The wattmeter must be powered
for at least 30 minutes for stable and accurate readings.
-
-
About this task
Overview
This procedure provides instruction to set up and calibrate
the maximum power for the RF amplifier. The procedure also proceeds
through the calibration and functional check of the Universal Power
Monitor (UPM) for each channel.
Use the UPM Tool to process each channel through each procedure.
For example, when you select head mode, the tool executes the RF amplifier
calibration and, if the amplifier passes, proceeds to the UPM calibration
and then to the functional check. The process is order-dependent.
Process the body channel first and then the head channel.
RF amplifier and UPM calibration are performed for forward power
on a channel. UPM functional check is performed after the channel
is calibrated.
Using Bird Wattmeter and Power Adjustment
Kit for RF Body Calibration
Setting up RF Coupler for Body Calibration
Procedure
Insert the 50 kW element into the Forward sensor port (green
4300A374-2). Lock the element in place using the locking tab on the
sensor. The Reflected port is not used during this procedure. Placing
the 5000 W element (green 4300A374-5) into the Reflected port is just
a safety measure, and is not used during body calibration.
Make sure the arrows on the elements point in opposite directions.
Figure 3. RF Coupler Setup for Body Mode
Use the DVM to measure the resistance of input to the dummy
load. Confirm that the resistance measures 50 ohms +/- 5 ohms.
Note:
If the dummy load is out of spec, return the RF kit for
repair. Do NOT proceed with the RF amplifier output calibration.
Wattmeter and Dummy Load Setup for Body Channel (XRFD Amplifier)
Procedure
DANGER
FATAL ELECTRIC SHOCK HAZARD!
THE RF AMPLIFIER IS NOT DISABLED.
TO PREVENT FATAL ELECTRIC SHOCK, ENSURE THE RF AMPLIFIER
IS DISABLED WHILE CONFIGURING THE CALIBRATION TOOLS.
Warning
ELECTRICAL/RF BURN HAZARD!
RF BURNS Can Occur AS A RESULT OF DISCONNECTING HELIAX CABLES
WHILE THE SYSTEM IS SCANNING.
PREVENT POSSIBLE RF BURNS WHEN DISCONNECTING HELIAX CABLES
FROM THE RF AMPLIFIER BY VERIFYING THAT THE SYSTEM IS NOT MANUALLY
PRESCANNING OR SCANNING. VERIFY THAT THE SCAN DESKTOP ICON DISPLAYS
THE “IDLE” MESSAGE AND THE RF ENABLE SWITCH IS IN THE
“OFF” POSITION.
Notice
Possible equipment damage. Do not connect/disconnect the wattmeter sensor while the meter is ON. Always turn the meter OFF before plugging/unplugging the sensor.
Verify that the scanner is idle. Confirm that the RF ENB switch
on the DTX1 exciter is in the Disable (down) position.
Disconnect the body output cable from J4 on the front panel
of the RF amplifie.
Connect the input of the coupler to J4 on the front panel of
the RF amplifier.
Figure 4. Connection of RF Coupler to Body Output
Warning
Electric shock risk!
Failure to connect the dummy load correctly could result
in electric shock.
pay close attention to the connections to the dummy load.
Connect the output of the RF coupler to the dummy load.
Figure 5. Complete Body Output Test Setup (16 kW XRFD Amplifier)
Plug in the wattmeter to use wall power (batteries are often
not charged). Connect one end of the wattmeter cable to the sensor
connector (RS232 is unused). Connect the other end to the coupler.
Notice
Do not apply RF power to the dummy load without its fan in operation. Doing so will result in catastrophic damage to the dummy load due to overheating.
Plug the fan for the dummy load into a service outlet located
in the upper right part of the PGR cabinet. Never use this dummy load without its fan running.
Set the RF ENB switch to ENABLE (up).
The power measurement kit can have one of two Bird wattmeters.
The setup instructions are different for each.
Press the ON button on the wattmeter.
(If the coupler and sensor are not correctly attached to the amplifier
you will see a “No Sensor” indication.)
Select the arrow ▲ button under Scale.
Enter 50000 to set the range.
Select the ENTER button.
Check the setting by selecting the arrow button under Scale.
Press the ENTER button to exit.
Select the arrow button under Fwd Units. Make sure the scale reads W (or kW on some
wattmeters). If the scale reads dBm, select the arrow button under Fwd Units again to toggle the scale to read W (Watts) or kW (kiloWatts) on the TOP, forward power
scale. Ignore the BOTTOM, reflected power scale value. It is not used
during maximum power calibration.
Select the SHIFT button.
Select the arrow button under Setup.
This displays the sensor type configured in the wattmeter. This
procedure uses sensor type 43, which is optimized for peak power measurement.
Verify that the output reads 43, and
then press the ENTER button.
Figure 7. Wattmeter Display Set to Read
Press the ENTER button.
Press the arrow ▲ button under Type and
then toggle to change the unit of measurement to Peak.
All kits require an offset to ensure accurate measurement. Locate
the Element Offset Factors card in the kit.
Find the offset for “1.5T Body Output.”
Figure 8. Example Element Offset Factors Card
Press the Offset button on the wattmeter.
Enter the numerical value from the offset card and press the Enter button.
Note:
To enter a negative value, first enter the numerical value,
then the minus symbol (–).
Press the MENU button. Press the ▼ button
to SCALE MENU, and then press OK.
Press 50000 to set the range, and then
press OK.
Check the setting by pressing ▼ to SCALE MENU, and then press OK.
Press OK to exit. Press ◄ to return to
measurement mode.
Press ▲ to make sure the scale reads W (or uW or kW on some wattmeters). If
the scale reads dBm, press ▲ again to toggle
the scale to read W (or uW or kW on the TOP, forward power scale. Ignore
the BOTTOM, reflected power scale value. It is not used during maximum
power calibration.
Press MENU.
Press ▼ to select ELEMENT TYPE, and then
press OK.
This displays the sensor type configured in the wattmeter. This
procedure uses sensor type 43, which is optimized for peak power measurement.
Verify that the output reads 43, and then
press OK.
Figure 11. Wattmeter Set to Read
Press OK. Press ◄ to return to measurement
mode.
All kits require an offset to ensure accurate measurement. Locate
the Element Offset Factors card in the kit.
Find the offset for “1.5T
Body Output.”
Figure 12. Example Element Offset Factors Card
Press the MENU button on the wattmeter.
Select OFFSET, and then press OK. Enter in the numerical value that was displayed on the kit’s
offset card and press OK. (The wattmeter rounds
to three significant digits.) Press ◄ to return to measurement mode.
Note:
To enter a negative value, first enter the numerical value,
and then the minus symbol (–).
Press MENU. Press ▼ until SMOOTHING is selected, and then press OK.
To verify that SMOOTHING has been set, press ▼until SMOOTHING is selected, and then press OK.
Using Agilent Wattmeter and
Power Adjustment Kit for RF Body Calibration
About this task
The Agilent wattmeter must be powered on for at least 30 minutes
for stable and accurate readings. Plug in the wattmeter and turn it
on at the beginning of this procedure.
Agilent Wattmeter Setup
Procedure
CAUTION
Possible equipment damage!
Physical shocks to the sensor and coupler (for instance,
dropping them) can damage them or cause them to go out of calibration.
Take care when handling the coupler and adapter. When connecting
to the sensor, hold the sensor steady and turn the knurled rings on
the connectors to tighten them. Take care not to cross-thread the
sensor connections.
Notice
Make sure the serial numbers for the RF coupler and RF sensor match each other. They are calibrated together, and should not be swapped between power measurement kits.
Set up the wattmeter for calibration as shown in the following
illustration.
Connect the Agilent sensor probe cable to the sensor.
Connect the sensor to the power reference (PWR REF) port on the wattmeter.
Connect the other end of the sensor probe cable to the Channel A port on the wattmeter.
Figure 14. Agilent Wattmeter Calibration Setup
1
Front of wattmeter
4
Zero/Cal button
2
Power reference (PWR REF) port
5
Channel A port
3
Agilent RF power sensor
6
Agilent sensor probe cable
On the front of the wattmeter, press Zero/Cal.
Press the Zero + Cal softkey to start
the calibration process.
The wattmeter displays a wait screen while it zeros. While the
wattmeter calibrates, a green LED next to the power reference port
turns on (indicating RF power is being transmitted from the reference
port). When this LED turns off, the calibration is complete.
If there is a calibration error, an error message appears on
the wattmeter screen. If this happens, check the connections to the
meter and sensor and press the Zero + Cal softkey
to re-run the calibration.
Note:
Expect to see a fluctuating low power reading on the wattmeter
on the order of ±3.0 dBm (± 2.0 mW) after it is calibrated.
Wattmeter and Dummy Load Setup for Body Mode (XRFD Amplifier)
Procedure
DANGER
FATAL ELECTRIC SHOCK HAZARD.
THE RF AMPLIFIER IS NOT DISABLED.
TO PREVENT FATAL ELECTRIC SHOCK, ENSURE THE RF AMPLIFIER
IS DISABLED WHILE CONFIGURING THE CALIBRATION TOOLS.
Warning
ELECTRICAL/RF BURN HAZARD.
RF BURNS Can Occur AS A RESULT OF DISCONNECTING HELIAX CABLES
WHILE THE SYSTEM IS SCANNING.
PREVENT POSSIBLE RF BURNS WHEN DISCONNECTING HELIAX CABLES
FROM THE RF AMPLIFIER BY VERIFYING THAT THE SYSTEM IS NOT MANUALLY
PRESCANNING OR SCANNING. VERIFY THAT THE SCAN DESKTOP ICON DISPLAYS
THE “IDLE” MESSAGE AND THE RF ENABLE SWITCH IS IN THE
“OFF” POSITION.
Notice
Possible equipment damage. Do not connect/disconnect the wattmeter sensor while the meter is ON. Always turn the meter OFF before plugging/unplugging the sensor.
Verify that the scanner is idle. Confirm that the RF ENB switch
on the DTX1 exciter is in the Disable (down) position.
Disconnect the body output cable from J4 one the front panel
of the RF amplifier:
Connect the input of the coupler to J4 on the front panel of
the RF amplifier:
Setting up Agilent Wattmeter to Measure Forward Body Maximum
Power
Procedure
Warning
Electric shock risk!
pay close attention to the connections to the dummy load.
Failure to connect the dummy load correctly could result in electric
shock.
Use a digital multimeter to measure the resistance between the
dummy load RF connector center pin and the shield. Confirm a reading
of 50 ohms (+/- 5 ohms). Replace the dummy load if the resistance
is out of range.
Connect the remaining Agilent power components as shown below.
Figure 15. Agilent Power Meter Setup for RF Body Calibration
1
RF amplifier (front)
6
RF cable to dummy load
2
RF output port
7
RF coupler
3
Wattmeter
8
Agilent 50 ohm terminator connected to the Reflected port on the coupler
4
Agilent sensor probe cable
9
Dummy load with internal fans
5
RF sensor connected to the Incident port
on the coupler
Connect one end of the RF sensor to the wattmeter. Connect the
other end to the coupler.
Notice
Do not apply RF power to the dummy load without its fan in operation. Doing so will result in catastrophic damage to the dummy load due to overheating.
Plug the fan for the dummy load into a service outlet located
in the upper right part of the PGR cabinet. Never use this dummy load without its fan running.
CAUTION
Possible equipment damage!
Physical shocks to the sensor and coupler (for instance,
dropping them) can damage them or cause them to go out of calibration.
Take care when handling the coupler and adapter.
Notice
Make sure the serial numbers for the RF coupler and RF sensor match each other. They are calibrated together, and should not be swapped between power measurement kits.
When the power meter has started, press Preset/Local.
The meter displays a list of predefined applications. Use the
up and down cursor keys to highlight 15T_BodyHead.
Perform a landmark for a body scan. A phantom is not needed.
(For non-proprietary mode) On the Common Service
Desktop, select Calibration > UPM Tool and select Click here to start this tool.
Make the following selections for the settings.
Table 6. Body Mode Settings for Single Drive RF Amplifiers
Setting
Value
Nuclei
1H
Task
Launch RF Cal
RF Chain
Body
Note:
Power Type is grayed out. This is
normal.
Select Start.
When a popup appears asking if the system is properly set up,
click Yes.
The system sets the proper sequence for RF calibration of the
selected body channel. This process takes about one minute.
When a popup titled RF Amp Calibration appears as shown Figure 16, do not select the Success or Failure button at this time. First,
go to the Scan Desktop as shown in Figure 17.
Figure 16. RF Amp Calibration Popup
Click the Patient icon to go to the Scan
workplace.
Figure 17. Patient Icon
In the Prescan Looping window, set Transmit Gain (TG) to 180.
Figure 18. Prescan Looping Window
Confirm that a reading of more than 1 kW is present on the wattmeter.
If the reading is zero or very low, then 1) confirm the correct
center frequency value and 2) select Done to
stop looping and recheck the test setup cabling.
If the amplifier trips, reset TG to the highest setting it reached
before tripping.
Note:
If Manual Prescan must be stopped and restarted, you must
relaunch the calibration sequence using the UPM Tool. Select Failure in the RF Amp Calibration popup (see Figure 16), and then click Start on the UPM Tool with
the same menu selections, to relaunch the calibration sequence.
Slowly increase TG to 200.
Note:
Allow 10 seconds for the meter reading to stabilize before
making the next adjustment.
Check the wattmeter to see if the reading is 16 kW ±
500 watts. If yes, proceed to the next step. If no, adjust the gain
for the body channel.
(For 16 kW XRFD amplifier) Rotate the single
HD/BDY adjustment encoder on the RF amplifier front panel and, if
necessary, increase the TG in small increments until the wattmeter
reads 16 kW ± 500 watts when the TG is 200. Only adjust while
the amplifier is actively pulsing. If output does not change, cycle
amplifier power, wait 10 minutes, and then repeat the adjustment again.
Figure 19. Gain Adjustment Controls
After the RF output is calibrated to specification, reduce TG
to 0 (zero) and then click Done.
From the scan desktop, click the CSD icon.
Figure 20. CSD icon
When the RF output is within specification, click Success on the RF Amp Calibration popup (see Figure 16). If the RF out put cannot be adjusted to spec, see: RF Amp Power Check Tool
Note:
The RF Amp Calibration popup may be hidden behind the ICW window. Move the ICW window to the left or right to see the RF Amp Calibration popup.
Click Yes to confirm that the RF output
calibration was successful.
After a few seconds, PASS appears in the
status area of the UPM Tool.
Calibrating UPM Forward Power for Body Channel
Procedure
Proceed to calibrating forward power for the UPM in body mode. On the UPM Tool, make the following selections:
Select Yes when the prompt asks if the
hardware setup is correct.
After approximately one minute, you are asked to confirm the
peak power value output from the amplifier.
If the power read from the power meter is within specification,
click Yes. Otherwise, click No and recheck the calibration of the RF amplifier.
The tool reports the steps as they progress. In about three
minutes, the Status field on the UPM Tool displays PASS or FAIL.
UPM Functional Check for Body Mode
About this task
After completing the UPM calibration, continue with the UPM functional check.
Procedure
From the UPM Tool, make the following selections:
Table 8. UPM Functional Check Selections for Single Drive RF Amplifiers
For this setting:
Select:
Nuclei
1H
Task
UPM Func Chk
RF Chain
Body
Note:
Power Type is grayed out. This is
normal and is not used.
Select Start.
Select Yes when the prompts ask if the
hardware is set up correctly.
Prompts are displayed during test execution, including a popup
message about the UPM tripping and a power trip error message. The
tool performs three tests before the host trip. This takes 2 to 3
minutes before any user interaction is required.
From the CSD, open the error log. Verify the error log contains
the message that the UPM has “detected a power fault on Body
Short Term Average.” Select Yes if an
error message is displayed.
Using Bird Wattmeter and Power Adjustment
Kit for RF Head Calibration
Setting up RF Coupler for Head Calibration
Procedure
Insert the 5 kW element into the Forward sensor port, (green
4300A374-5). Make sure the arrow on the element points in the direction
of the arrow (from Input to Output) on the sensor. Lock the element
in place using the locking tab on the sensor.
Figure 21. RF Coupler Setup for Head
Mode
Insert the 50 kW element into the Reflected sensor port (green
4300A374-2). Make sure the arrows on the elements point in opposite
directions. Lock the element in place using the locking tab on the
sensor. (See Figure 21).
The Reflected port is not used during this procedure. Placing
the 50 kW element into the Reflected port is a safety measure.
Use the DVM to measure the resistance of input to the dummy
load. Confirm that the resistance measures 50 ohms +/- 5 ohms.
Note:
If the dummy load is out of specification, return the
RF kit for repair. Do NOT proceed with the RF amplifier output calibration.
Wattmeter and Dummy Load Setup for Head Mode
Procedure
Verify that the scanner is idle. Confirm that the RF ENB switch
on the DTX1 exciter is in the Disable (down) position. See Figure 2.
Disconnect the head output cable from J3 on the front of the
RF amplifier:
Connect the input of the coupler to J3 on the front of the RF
amplifier:
Figure 22. Connection of RF Coupler to Head Output
Warning
Electric shock risk!
Failure to connect the dummy load correctly could result
in electric shock.
pay close attention to the connections to the dummy load.
Connect the RF coupler output to the dummy load.
Figure 23. Complete Head Output Test Setup
Plug in the wattmeter to use wall power (batteries are often
not charged). Connect one end of the wattmeter cable to the wattmeter
sensor output connector (RS232 is unused). Connect the other end to
the coupler.
Plug the fan for the dummy load into a service outlet in the
PGR cabinet. Never use this dummy load without
its fan running.
Notice
Do not apply RF power to the dummy load without its fan in operation. Doing so will result in catastrophic damage to the dummy load due to overheating.
Set the RF ENB switch to ENABLE (up).
The power measurement kit can have one of two Bird wattmeters.
The setup instructions are different for each.
Press the ON button on the wattmeter.
(If the coupler and sensor are not correctly attached to the amplifier,
you will see a No Sensor indication).
Select the arrow button under Scale.
Type 5000 to set the range and then press Enter.
To validate the setting, select the arrow button under Scale.
To exit, press Enter.
Select the arrow button under Fwd Units. Make sure the scale reads W (or kW on some wattmeters). If the scale reads dBm, select the arrow button under Fwd Units again to toggle the scale
to read W (or kW) on the
TOP, forward power scale. Ignore the BOTTOM, reflected power scale
value. It is not used during maximum power calibration.
Select the Shift button.
Select the arrow button under Setup.
This action displays the sensor type configured in the wattmeter.
This procedure uses sensor type 43, which is optimized for peak power
measurement.
Verify that the wattmeter display reads 43. If not, type 43 and then press Enter.
Figure 24. Wattmeter Display Set to Read Sensor Type
Press Enter.
Select the arrow button under Type, and
change the unit of measurement to Peak.
Some kits require an offset to ensure accurate measurement.
Locate the Element Offset Factors card in the kit.
Find the offset for “1.5T Head Output,” 2000 W.
Figure 25. Example Element Offset Factors Card
Press the Offset button on the wattmeter.
Enter the numeric value from the offset card, and press Enter.
Note:
If entering a negative value, first enter the numerical
value, then the minus symbol (–).
Figure 26. Wattmeter Set to Display Peak Power and Watts
The meter is now configured to read RF peak power, in watts,
for the head maximum output calibration.
Press MENU. Press ▼ to SCALE
MENU, and then press OK.
Type 5000 to set the range, and then press OK.
Check the setting by pressing ▼ to SCALE MENU, and then press OK.
Press OK to exit. Press ◄ to return to
measurement mode.
Press ▲ to make sure the scale reads W (or uW or kW on some wattmeters). If
the scale reads dBm, press ▲ again to toggle
the scale to read W (or uW or kW) on the TOP, forward power scale. Ignore
the BOTTOM, reflected power scale value. It is not used during maximum
power calibration.
Press MENU.
Press ▼ to select ELEMENT TYPE. Press OK.
This action displays the sensor type configured in the wattmeter.
This procedure uses sensor type 43, which is optimized for peak power
measurement.
Verify that the wattmeter display reads 43. If not, type 43 and then press OK.
Figure 27. Wattmeter Display Set to Read
Press OK. Press ◄ to return to measurement
mode.
Press ► button repeatedly to change the unit of measurement
to Forward Peak.
Some kits require an offset to ensure accurate measurement.
Locate the Element Offset Factors card in the kit.
Find the offset for “1.5T Head Output,” 2000 W.
Figure 28. Example Element Offset Factors Card
Press MENU on the wattmeter. With OFFSET
selected, press OK. Enter the numerical value
from the offset card and press OK. (The wattmeter
rounds the number to three significant digits.) Press ◄ to return
to measurement mode.
Note:
If entering a negative value, first enter the numerical
value, then the minus symbol (–).
Press MENU. Press ▼ until SMOOTHING is selected, and then press OK.
Press ▼ until 4 Samples is displayed, and
then press OK.
To verify that the SMOOTHING has been set, press ▼ until SMOOTHING is selected, and then press OK.
The wattmeter should read 4 Samples. Press OK.
Press ◄ to return to measurement mode.
Figure 29. Wattmeter Set to Display Peak Power and Watts
Using Agilent Wattmeter and
Power Adjustment Kit for RF Head Calibration
About this task
Confirm that the Agilent wattmeter is still powered on. If the
wattmeter has been turned off, it must be powered for at least 30
minutes for stable and accurate readings. The wattmeter must also
be zero calibrated Agilent Wattmeter Setup.
Procedure
Use a digital multimeter to measure the resistance between the
dummy load RF connector center pin and the shield. Confirm a reading
of 50 ohms (+/- 5 ohms). Replace the dummy load if the resistance
is out of range.
Before setting up the wattmeter and dummy load for head mode,
verify that the scanner is idle. Confirm that the RF ENB switch on the DTX1 exciter is in the Disable (down) position. See Figure 2.
Disconnect the head output cable from J3 on the front of the
RF amplifier:
Connect the input of the coupler to J3 on the front of the RF
amplifier:
Connect the remaining Agilent power components as shown below.
Figure 30. Agilent Wattmeter Setup for RF Power Output for Head
1
RF amplifier (front)
6
RF cable to dummy load
2
RF output port
7
RF coupler
3
Wattmeter
8
Agilent 50 ohm terminator connected to the Reflected port on the coupler
4
Agilent sensor probe cable
9
RF adapter
5
RF sensor connected to the Incident port
on the coupler
10
Dummy load with internal fans
Connect one end of the RF sensor to the wattmeter. Connect the
other end to the coupler.
Notice
Do not apply RF power to the dummy load without its fan in operation. Doing so will result in catastrophic damage to the dummy load due to overheating.
Plug the fan for the dummy load into a service outlet in the
ISC cabinet. Never use this dummy load without
its fan running.
Adjusting RF Amplifier Output Power for Head Mode
Procedure
Set RF ENB to ENABLE (up).
Press Landmark. Then, advance to scan. A phantom is not needed.
Note:
No phantom is needed since dummy command for head connection
is set in UPM Tool Head mode for SIGNA Voyager.
Figure 31. Adv to scan
On the UPM Tool, make the following selections for the settings.
Table 9. Head Mode Settings
Setting
Value
Nuclei
1H
Task
Launch RF Cal
RF Chain
Head
Note:
Power Type is grayed out. This is
normal.
Select Start.
When a popup appears asking if the system is properly set up,
click Yes.
A message displays asking if you have completed the body mode.
Click Yes.
The system sets the proper sequence for RF calibration. This
process takes about one minute.
When a popup titled RF Amp Calibration appears, do not select
either the Success or Failure button at this time. First, go to the
Scan Desktop.
Click the Patient icon (shown in Figure 17) to go to the Scan workplace.
In the Scan workplace, click the patient model to open the manual
prescan window.
Slowly move the Transmit Gain (TG) slider to 180. Make sure
everything is functioning normally and there is a reading on the wattmeter.
Slowly increase the TG to 200 (if the amplifier
trips, reset the TG to the highest setting it reached before tripping).
Check the wattmeter to see if the reading is 2000 watts (2.0
kW) ± 100 watts. If yes, proceed to the next step. If no, adjust
the gain for the head channel.
(For 16 kW XRFD amplifier) Rotate the single
HD/BDY adjustment encoder on the RF amplifier front panel and, if
necessary, increase the TG in small increments until the wattmeter
reads 2kW ± 100 watts when the TG is 200. Only make adjustments
while the amplifier is pulsing. If the output does not change, cycle
the amplifier power. Wait 10 minutes and then repeat the adjustment
process.
Allow 10 seconds for the meter reading to stabilize before the
next adjustment.
After the RF output is calibrated to specification, reduce the
TG to 0 (zero).
From the scan desktop, click the CSD icon (see Figure 20).
If the RF output is within specification, click Success on the RF Amp Calibration popup.
Note:
The RF Amp Calibration popup may be hidden behind the
ICW window. Move the ICW window to the left or right to see the RF
Amp Calibration popup.
Click Yes to confirm that the RF output
was successful.
After a few seconds, PASS appears in the
status area of the interface.
UPM Calibration for Head Mode
Procedure
Proceed to calibrating the UPM in head
mode.
Table 10. UPM Calibration for Head Mode
For this setting:
Select:
Nuclei
1H
Task
Calibrate UPM
RF Chain
Head
Power Type
Forward
Select Start.
Select Yes when the prompt asks if the hardware setup is correct.
After approximately one minute, you are asked to confirm the
peak power value output from the amplifier.
If the power read from the power meter is within specification,
click Yes. Otherwise, click No and recheck the calibration of the RF amplifier.
The tool reports the steps as they progress. In about three
minutes, the Status field on the UPM Tool displays PASS or FAIL.
UPM Functional Check for Head Mode
Procedure
After completing the UPM calibration, continue with the UPM functional check.
On the UPM Tool, make the following selections:
For this setting:
Select:
Nuclei
1H
Task
UPM Func Chk
RF Chain
Head
Note:
Power Type is grayed out. This is
normal and is not used.
Select Start.
If the functional check passes, select Quit.
After the RF amplifier and UPM are calibrated for head mode,
proceed to Finalization.
Finalization
Procedure
Warning
ELECTRICAL/RF BURN HAZARD!
RF BURNS Can Occur AS A RESULT OF DISCONNECTING HELIAX CABLES
WHILE THE SYSTEM IS SCANNING.
PREVENT POSSIBLE RF BURNS WHEN DISCONNECTING HELIAX CABLES
FROM THE RF AMPLIFIER BY VERIFYING THAT THE SYSTEM IS NOT MANUALLY
PRESCANNING OR SCANNING. VERIFY THAT THE SCAN DESKTOP ICON DISPLAYS
THE “IDLE” MESSAGE AND THE RF ENABLE SWITCH IS IN THE
"OFF" POSITION.
Notice
Possible equipment damage. Do not connect/disconnect the wattmeter sensor while the wattmeter is ON. Always turn the wattmeter OFF before plugging/unplugging sensor.
Set the RF ENB switch to DISABLE (down).
Adjust connections as disconnect the RF coupler from J3 and
reconnect the head transmit line.
Re-enable the TR and DD fault switches on the front of the driver
module. See Figure 1.
Set RF ENB switch to ENABLE (up).
Confirm that the other RF amplifier system cables are reconnected
to their correct locations for clinical scanning.
Note:
