American Magnetics 03300PS-430-601 High Stability Integrated Power Supply System - Manual (Page 53)

Rev. 5 35
Operation
Single-key Commands : Target Field Setpoint
seconds within the Load submenu
1
. The default cooling period of 20
seconds is adequate for the majority of wet persistent switches.
Conduction cooled switches typically require longer time to transition from
resistive to superconducting.
The default cooling gain of 0.0% may be adequate for the majority of wet
persistent switches. However, this setting may result in some magnet drift
during persistent switch cooling, especially with conduction cooled
switches. Increasing the cooling gain adds control loop gain during the
switch cooling cycle. Too little may result in magnet drift during switch
cooling. Too much may result in power supply instability during switch
cooling, which could potentially prevent the switch from cooling. Most
systems requiring some cooling gain to control magnet drift will likely
work with value set to 25%.
Note
During the period the switch is being heated or cooled, the Model
430 Programmer will not allow ramping functions to be executed
and will beep once if the user attempts to initiate a ramping
operation.
Refer to section 3.13 on page 81 for a complete description of magnet
persistent switch control. A flowchart of the persistent switch control
functions are located in the Appendix beginning on page 199.
3.6.2 Target Field Setpoint Key
Pressing the TARGET FIELD SETPOINT key provides a menu for setting
the target field/current. The target field/current is the field or current to
which the Model 430 Programmer ramps the superconducting magnet
when it is not paused. The target field/current may be set to the lesser of
(1) the Magnet Current Rating, and (2) the Current Limit 2 or equivalent
field (per defined coil constant). The target field/current does not require a
sign (attempting to enter a negative value will cause the Model 430
Programmer to produce one beep to indicate an error).
When on the default display, pressing the SHIFT + TARGET FIELD
SETPOINT keys will temporarily display the Magnet Current/Field for
1. Refer to section 3.10.2.10 on page 60.
2. Refer to section 3.10.2.4 on page 56.
+50.00 A - Target Field (kG)
+0.50 Vs +50.000