• Topic ID: id_11038895
  • Version: 3.0
  • Date: Apr 22, 2019 12:56:01 AM

Generator Software (LS16, Ultra, Plus)

1 Functional Overview

The generator software runs on the kV control CPU. Its main functions are:

  • Console and/or system communication

  • Exposure sequencing (rotation, heater, exposure control, mA regulation)

  • Tube/generator thermal protection

  • Tube/generator tracking

  • Generator diagnostics (application background diagnostics and service diagnostics)

2 System Communication

The generator has CAN communication capabilities.

Each communication path is connected to the application software through a communication driver. This mechanism allows:

  • The same generator behavior regardless of the communication path used to drive the generator.

  • Connecting several interfaces at the same time on the generator

3 Exposure Sequencing

See kV, mA and rotation functions.

4 Tube/Generator Thermal Protection

The generator software simulates HV power inverter, HV tank and tube temperature in real time.

These algorithms are based on generator and tube models. They use the real kV and mA applied to the tube.

They are used to:

  • Protect the generator and tube against overloads.

  • Predict the exposure parameters/number of exposures allowed based on the current generator and tube thermal status.

The algorithms parameters are tube and generator power dependent. They are included in the tube and generator database downloaded in the generator during manufacturing integration or installation.

Depending on the system using the generator, the algorithms can be either active or inhibited.

For CT systems, the tube thermal algorithm included in the generator is inhibited. Tube protection is managed at the OC level.

4.1 Calibration

There is no manual calibration on Jedi 60DC.

Automatic Calibration: Filament Aging

Tube filaments are aging during the tube life leading to mA inaccuracy. In order to get accurate mA, the mA accuracy is tracked over the entire tube life:

  • At the beginning of each exposure, the difference between the mA demand and the real mA is measured.

  • The drift is recorded. It is used with a slow time constant to correct the filament drive initial values.

  • During the generator's life, the software logs the drift on both focal spot in the generator saved RAM.

4.2 Tube Spits Counting

The generator software counts the number of tube spits occurring during an exposure.

The count generates an error if:

  • The number of tube spits exceeds the maximum number allowed for the medical application (CT applications: (100+8*T) spits where T is the exposure time in seconds).

  • the tube spits rate exceeds the maximum allowed for the medical application (CT applications: 20 spits/0,1s or 32spits/sec.)

In both cases, the exposure is stopped and the error is reported to the system.

If the count does not exceed the limits, the number of spits is reported to the system at the end of the exposure.

During all the generator life, the software adds the number of tube spits detected and log it in the generator saved RAM.

5 Generator Usage Tracking and Trending (TnT)

During generator life, the software logs in the saved RAM (JEDI database) the following parameters: