American Magnetics 05500PS-430-601 High Stability Integrated Power Supply System - Manual (Page 54)

36 Rev. 5
Operation
Single-key Commands : Persistent Switch Control
switch was cooled at the rate set by the PSw P/S Ramp Rate variable and
then the persistent switch heater is energized.
Pressing SHIFT followed by the PERSIST. SWITCH CONTROL key toggles
the Model 430 Programmer persistent switch heater between energized
(turned on) and de-energized (turned off). If the persistent switch heater is
energized and this key is pressed, the persistent switch heater is de-
energized. If the persistent switch heater is de-energized and this key is
pressed, the persistent switch heater is energized.
Note
The power supply current is unchanged when SHIFT + PERSIST.
SWITCH CONTROL is used. Only the state of the persistent switch heater
is changed.
When the persistent switch heater is energized, the Model 430
Programmer is supplying current to the appropriate pins (9 & 10) of the
Magnet Station Connectors in order to drive the persistent switch into a
normal state, which takes the magnet out of persistent mode. Magnet
persistent mode is indicated by the MAGNET IN PERSISTENT MODE
LED
1
.
The Model 430 Programmer will beep once (indicating an error) if the user
attempts to activate the switch heater control without first indicating a
persistent switch is installed in the Load submenu and specifying the
switch heating current, heated time, and cooled time 2 .
The nominal switch heating current is listed on the magnet specification
sheet, and may be entered in the Model 430 Programmer by accessing the
Load submenu 3 . In addition to the heating current, the user must also
specify a heated time, cooled time, PSw P/S Ramp Rate and cooling gain.
The heated time allows the Model 430 Programmer to delay compensating
the internal control logic until the magnet is guaranteed to be in the
circuit. The heated time can be set from a minimum of 5 seconds to a
maximum of 120 seconds within the Load submenu 4 . The default heating
period of 20 seconds is adequate for the majority of persistent switches.
If the magnet appears unstable just after the switch heating period
expires, increase the switch heated time to allow for complete heating. The
cooled time allows the persistent switch sufficient time to be cooled to
superconducting state before the current is changed in the magnet. The
cooled time can be set from a minimum of 5 seconds to a maximum of 3600
1. Refer to section 3.8.2.2 on page 46.
2. Refer to section 3.10.2.6 on page 60, section 3.10.2.8 on page 61, section 3.10.2.9
on page 61, and section 3.10.2.10 on page 62.
3. Refer to section 3.10.2.8 on page 61.
4. Refer to section 3.10.2.9 on page 61.