Lake Shore 625, User Manual

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Lake Shore Model 625 Superconducting MPS User’s Manual
Introduction 1-3
Parallel Operation
If an application requires more output current than a single Model 625 can provide, two supplies can be connected in
parallel for 120 A/5 V operation. Each unit is programmed for half of the total output current, operates independently,
and retains 0.1 mA resolution at 60 A operation. When the units are properly configured, either unit can detect a fault,
protect itself, and issue a fault output signaling the other unit to automatically enter the proper protection mode.
Persistent Switch Heater Output
The integrated persistent switch heater output is a controlled DC current source capable of driving most switch heaters. It
sources from 10 mA to 125 mA with a setting resolution of 1 mA and selectable compliance voltage of 12 V or 21 V.
The minimum load that the persistent switch heater can drive is 10 W. Persistent mode operation is integrated into the
instrument firmware to prevent mis-operation of the magnet.
Interfaces
The Model 625 includes IEEE-488 and RS-232C interfaces that provide access to operating data, stored parameters, and
remote control of all front panel operating functions. In addition, the Model 625 includes a trigger function that is used to
start an output current ramp. When the trigger is activated, either by an external trigger or by computer interface
command, the power supply will begin ramping to the new setpoint.
The Model 625 provides two analog outputs to monitor the output current and voltage. Each output is a buffered,
differential, analog voltage representation of the signal being monitored. The current monitor has a sensitivity of 1 V =
10 A, while the voltage monitor has a sensitivity of 1 V = 1 V.
Display and Keypad
The Model 625 incorporates a large 8-line by 40-character vacuum fluorescent display. Output current, calculated field
in tesla or gauss, output voltage, and remote voltage sense readings can be displayed simultaneously. Five LEDs on the
front panel provide quick verification of instrument status, including ramping, compliance, fault, PSH status, and
computer interface mode. Error conditions are indicated on the main display along with an audible beeper. Extended
error descriptions are available under the Status key.
The keypad is arranged logically to separate the different functions of the instrument. The most common functions of the
power supply are accessed using a single button press. The keypad can be locked to either lock out all changes or to lock
out just the instrument setup parameters allowing the output of the power supply to be changed.
625_Front.bmp
Figure 1-1. Model 625 Front Panel