Liquid Bearing Tube Service Tool Impact

1 General

This document describes Service Tool Impact when VCT system is with Liquid Bearing Tube.

2 Liquid Bearing Tube Rotor management

Liquid Bearing Tube requires unique rotor management in order to prevent rotor damage. The followings are basic constraint of rotor management.

Gantry rotates 2sec./rev. when rotor acceleration starts. (Some Service Tools can rotor start without the rule as exception)
Rotor rotating speed is Low or High. Usually rotor rotates with High Speed and it decelerates to Low speed 20min. past after End exam event.
Rotor rotates continuously unless E-Off, HVDC Off, or some service tools execution.
Rotor acceleration is required manually when rotates gantry faster than 2 sec./rev. because it does not start automatically.

Dedicated rotor control tool for Service engineer was implemented to manipulate rotor start or stop in any time (Refer to Rotor Control Tool for Liquid Bearing Tube (VCT) manual for details).

And Liquid Bearing Tube unique gesyslog messages were also implemented (refer to gesyslog for Liquid Bearing Tube (VCT) manual for details).

Refer to the following Table for each Service Tool impact.

Table 1. Service Tool impact by Liquid Bearing Tube VCT system
Service Tool Impact	Differences from Ball Bearing System
Generator Tool - JEDI	Scan is aborted at faster Gantry speed than 2sec./rev. when rotor is NOT rotating. The information is posted to gesyslog message. Use "rotor_ctrl -start" command to start rotor. Use "rotor_ctrl -start" command to start rotor.
Detailed Cal.	Gantry Balance is skipped in case of SP2.2 installed at both of Bearing type selection.
Collimator Functional	Before the tool starts, use "rotor_ctrl -start" command to start rotor for high speed (1.0sec./rev. or faster) Gantry rotation.
Axial Functional	Before the tool starts, use "rotor_ctrl -start" command to start rotor for high speed (1.0sec./rev. or faster) Gantry rotation.
DAS Tools	Scan is aborted with gesyslog message at the following conditions. 1. Rotate Gantry faster than 2sec./rev. without rotor High speed. 2. Select Rotor Off at Option setting with Gantry rotation faster than 2sec./rev. 3. X-ray Off scan (0mA scan) with Gantry rotation faster than 2sec./rev. Check gesyslog message when scan is aborted. Check gesyslog message when scan is aborted. Note: Option setting of rotor on/off is ignored at Auto Test. (Same as Ball Bearing)
Scan Data Path	Rotor becomes high speed at any combination of Scan protocol automatically.
DDC	Scan is aborted with gesyslog message at the following conditions. 1. Rotate Gantry faster than 2sec./rev. without rotor High speed. 2. Select Rotor RxOverrides Off setting with Gantry rotation faster than 2sec./rev. 3. X-ray Off scan (0mA scan) with Gantry rotation faster than 2sec./rev. This scan can be available by setting Rotor RxOverrides to ON. Check gesyslog message when scan is aborted. Error: 260100193 Gantry rotation of faster than 2.0 sec/rot was requested although Liquid Bearing tube rotor is not rotating. Rejected the request because it will do fatal damage to the tube.
Gantry Service Balance	The tool can't start up without using "rotor_ctrl -start" command to start rotor for high speed (1.0sec./rev. or faster) Gantry rotation. Use "rotor_ctrl -start" tool to start rotor at first.
Flash Download	The tool starts and aborted when rotor is rotating. Stop rotor by using "rotor_ctrl -stop" command when "update" is executed. Otherwise the Tool is aborted.
Cold ISO, Tube Alignment	Filament Cal., HHS Scan and Hot ISO has been moved after Gantry Cover Installation in order to prevent “Hot landing” of X-ray Tube rotor.

Other Service impact	Differences from Ball Bearing System
Gantry Service Switch Panel	1. Rotation speed at "Manual high speed" became 2sec./rev. from 1sec./rev. 2. It's recommended to wait before turning off HVDC or 120VAC if X-ray tube is hot. When Hot ISO, heat soak or Detail cal are done, they bring the tube to full hot and need to waiting until the casing is cool.
System shutdown	Rotor rotates 30min. continuously (low speed) after system shutdown, and High Voltage for HV system is alive. Be careful when turn off HVDC or 120VAC, refer to Service impact about Gantry Service Switch panel.
LFC	Warning Pop-up message is displayed at LB Tube installed without Service Pack 2.2. Need to install SP2.2 at VCT Liquid Bearing Tube because it will cause of Tube fatal damage without the patch. The following pop-up message is displayed during start up. Tube Identification not detected. Please contact Service. Scanning is permitted.

3 SWHWINFO / CHECK_CONFIG

New Tube type has been added for VCT LB Tube. The following shows the comparison of Tube type and example.

Ball Bearing: H
Liquid Bearing: NV

Example:

{ctuser@bay}[1] swhwinfo <Enter>
12HW14.6_SP2-2-1.V40_H_V64_G_GTM (Hercules)
12HW14.6_SP2-2-1.V40_NV_V64_G_GTM (VCT LB)
{ctuser@bay}[2]

4 Tube rotor damage prevention

Follow to the procedure VCT Liquid Bearing Tube Rotor Control Thermal Guidance for Hot landing prevention to prevent X-ray Tube rotor damage.

5 Pop-up message for Hot landing prevention

The following pop-up will appear. This is to notify FE to confirm Tube temperature is less than 210 deg. C. This message also appears when Ball Bearing tube (BB Tube) is installed, press “Proceed” anytime at BB Tube installed system. Refer to the Table 1 in case of pop-up appears.

Table 2. Tool list with attention pop-up
Service Tool (Refer to the list below for affected sub-menu)	Sub menu
Gen Tool	Meter Verification Gate Command in kV Diagnostics No Load KV in kV Diagnostics Inverter Short Circuit in kV Diagnostics Heater Diagnostics Fan Diagnostics Rotor Diagnostics Initialize Database Save Runtime Parameters Restore Runtime Parameters
DDC	Static X-ray off with rotor override default Static X-ray off with rotor override off Rotating X-ray off with rotor override default Rotating X-ray off with rotor override off
System Reset	• Scan
DAS Tool	Auto Test Pop Noise & Micro with Rotor Off Rotating Noise in Manual Test with Rotor Off Plateau Noise Manual test DC Noise Offset in Manual test