American Magnetics 430, Инструкции по установке, эксплуатации и обслуживанию

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R
EV
9 201
A
MERICAN
M
AGNETICS
, I
NC
. A
PPENDIX
: Q
UENCH
I/O C
ONNECTOR
is in driven mode, the Model 430 Programmer ramps the magnet field/
current to zero. If the magnet is in persistent mode, the Model 430
Programmer ramps the power supply to match the last known persistent
magnet current, turns on the persistent switch heater, waits the specified
heated time (or detects the transition using the magnet voltage per the
PSwitch Transition
setting
3
) and then ramps the magnet field/current to
zero.
This function may be used with the AMI Model 1700 Liquid Level
Instrument
4
. The level instrument has a NO relay associated with the low
level condition and this contact closure can be connected to the External
Rampdown Input so that when a low helium level occurs in a system, the
magnet is safely and automatically ramped down, preventing a magnet
quench. AMI offers a cable for this purpose or the user can make a
suitable cable to connect pins 5 and 6 of the Aux I/O connector of the
Model 1700 instrument to pins 6 and 7 of the 430 Programmer, Quench
I/O connector.
CAUTION
The separate external segmented-rampdown option
described below ignores the Voltage Limit during the
rampdown process.
NOTE
If the number of external-rampdown ramp segments is set to
zero, the modified rampdown is not used and the standard ramp
rate table will be effective during external rampdown. The Model
430 Programmer defaults to an empty rampdown table (number
of segments equal zero).
A separate, optional segmented-ramp-rate table is available for external
rampdown. This option is accessible only via the external interface
commands (see page 167).
E
XTERNAL
Q
UENCH
D
ETECTION
O
UTPUT
The external quench detection output is a set of dry contacts (pins 1 and
2 of the Quench I/O connector) which
close
when the Model 430
Programmer internal circuitry detects a quench condition. Note that the
Model 430 Programmer internal quench detection must be enabled to
assure that the Model 430 Programmer will indicate a detected quench
(see page 89).
The contacts remain shorted (when a quench has been detected) until
the
RESET QUENCH
SHIFT-key is used to clear the quench condition.
3. See page 85.
4. Or the Model 13x series of Liquid Helium Level Instruments for legacy systems.