There exists an invisible object whose task it is to keep track of the settings of the various current supplies connected to the conductors of the configuration. To change the settings of the current supplies, bring up an edit window using the Modify menu. The Specs page is a table of current supplies. The first entry of each row of the table is the supply name (any text without blanks) and the second entry is the associated current in amps.
On the Bias page, the bias box is provided to permit specification of a uniform bias field to be applied in the z direction. The units of bias are Tesla. Set it to zero if you do not want a bias field applied to your configuration.
Once you have modified the currents, the changes must be registered by pressing the Set or Done button. If AutoRecompute is enabled, the magnetic field will be recalculated immediately to reflect the new current supply and bias field settings.