Removing Active Shim Coils

1 Overview

The ShimConfig.cfg file is located in /usr/g/w/config and contains the following information for each coil:

harmonic naming order
current calculation; on or off
existing coil current value
pertubation current value
maximum power supply current
power supply or gradient coil name
harmonic name.

The vi editor is used to edit this file.

2 Coil Removal

At the operator workspace, select the Tools icon in the desktop control panel.
In the Service Browser, select the Calibration tab, then in the menu options on the left side of the browser, click LVShim. On the right side, click the link Click here to start this tool. Refer to Table 1.

Table 1. COIL REMOVAL
{unix prompt} ..................................	cd /usr/g/w/configEnter
{unix prompt} ..................................	Verify the file exists ls -al Shim.Enter ShimConfig.cfg is part of Load From Cold software.
If ShimConfig exists, the following is displayed: -rw-rw-rw- 1 sdcbin informix 7973 Sep20 18:25 ShimConfig.cfg	vi ShimConfig.cfg to edit the file. 1. Move cursor to appropriate coil set. 2. Position on the line of the power supply to be turned off. 3. Move cursor to 2nd column of line and change the 1 to 0. 4. Exit vi saving changes. The power supply with 0 in the 2nd column has been eliminated from the coil matrix.