Lake Shore Model 475 Gaussmeter User’s Manual
Advanced Operation
5-5
5.2.2
Ohms Measurement Mode
The Model 475 may be configured to make a 4-lead resistive measurement. If the sensitivity of the probe is set to 0, the
instrument will read in ohms. Instrument features are limited in this mode. The following ranges are available in this
mode: 350 µ
Ω
, 3.5 m
Ω
, 35 m
Ω
, 350 m
Ω
, 3.5
Ω
, 35
Ω
, and 350
Ω
. The available ranges are dependant on the hall
current selected (100 mA, 10 mA, or 1 mA).
5.3
FIELD CONTROL
The Model 475 includes algorithms to perform electromagnet field control. The Analog Output 3 is used to program a
voltage controlled magnet power supply.
5.3.1
Control On/Off setting
The Model 475 is capable of closed loop (PI) control. The control mode may also be set to Off, which sets the control
output to zero. If a key related to control is pressed when control is off, a message will appear, indicating that control is
off and needs to be configured.
NOTE
: Since the field control uses Analog Output 3, if control is turned On, the Analog Output 3 mode will be set to
Control. If control is then turned Off, the Analog Output 3 mode will be set to Off and the user must press the Analog
Output key to reconfigure the output.
To begin control setup, press the
Control
key. The first control setup screen appears as a prompt for turning control On
or Off. If control is already On, this screen will be skipped and the setpoint change screen will appear.
Sel ec t Wi t h ° ®
Co n t r o l Of f
Use the
s
or
t
key to select from Off or On. Press
Enter
to accept the new selection and continue to the next setting
screen. Press
Escape
to cancel the selection and return to the normal display.
5.3.2
Changing Control Setpoint
If control is turned On, the control setpoint indicates the desired magnetic field. It may be expressed in gauss, tesla,
oersted, or amp/meter.
To change the control setpoint, press the
Control
key. The control setpoint screen appears as a prompt for entering the
control setpoint.
Ent er f or Cont r ol
CSP +1 . 0 0 0 0 0 k G
Use the data entry keys to enter the setpoint between ±350 kG or equivalent depending on selected field units. Enter the
numeric value first. Press
Enter
to accept the new value and advance to the units multiplier. Use the
s
or
t
key to
select a units multiplier of µ, m, blank, k or M, depending on selected field units. Press
Enter
to accept the new selection
and continue to the next setting screen. Press
Escape
to restart the setting sequence and enter a new value. Press
Escape
again to cancel the sequence and return to the normal display.
NOTE
: When Setpoint Ramp is enabled (Refer to 5.3.4), the instrument will start ramping from the current field reading
rather than the current setpoint.
Содержание 475
Страница 16: ...Lake Shore Model 475 Gaussmeter User s Manual 1 6 Introduction 1 4 SAFETY SYMBOLS ...
Страница 25: ...Lake Shore Model 475 Gaussmeter User s Manual Background 2 9 Figure 2 8 Examples of PI Control ...
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Страница 68: ...Lake Shore Model 475 Gaussmeter User s Manual 4 32 Operation This Page Intentionally Left Blank ...
Страница 82: ...Lake Shore Model 475 Gaussmeter User s Manual 6 6 Remote Operation Figure 6 2 Model 475 Status System ...