American Magnetics 430, Инструкции по установке, эксплуатации и обслуживанию

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R
EV
9 85
A
MERICAN
M
AGNETICS
, I
NC
. O
PERATION
: S
ETUP
S
UBMENU
D
ESCRIPTIONS
: S
WITCH
S
UBMENU
the value determined in step 4 above is discarded and the previously
set persistent switch current is retained.
PS
WITCH
C
URRENT
The persistent switch heater current can be manually set to any
value between 0.0 and 125.0 mA. The value can be set by using
either the numeric keypad as described on page 54 or the fine
adjust knob (on page 55). The default value is 10.0 mA unless
preset by AMI to match a specific superconducting magnet.
PS
WITCH
T
RANSITION
The persistent switch transition (from heated-to-cooled and vice-
versa) can be detected by one of two methods: timer-based or by
direct sensing of the magnet voltage.
The timer-based method is the default and simply uses heated
and cooled state timers as entered by the operator in the PSwitch
Heated Time and PSwitch Cooled Time settings.
Optionally, the operator can choose to use the magnet voltage
method. This method works by directly sensing the running mean
and variance of the magnet voltage and comparing them to
preset limits. This method has the advantage of typically
requiring much less time to sense the transition of the persistent
switch from the heated to cooled state.
NOTE
In order to use the magnet voltage switch transition detection,
higher resolution of the magnet voltage measurement is
necessary. This is achieved by connecting the magnet voltage to
Auxiliary Input 1, which has a ±1.0 VDC input range with 20 times
more resolution (~0.5 mV/bit) than the standard magnet voltage
input.
Model 430 units that ship with version 3.00 or later firmware
installed have internally connected the magnet voltage input from
the Magnet Station connector to the Auxiliary Input 1 (therefore,
the Auxiliary Input 1 is consumed and is not available for general
use). For older, already fielded units the user will be required to
+50.00 A — PSwitch Current (mA)
+0.50 Vs 10.0
+50.00 A — PSwitch Transition
+0.50 Vs Timer Magnet Voltage