Agilent Technologies E7002, Reference Manual

Page: 16 / 33

16 E7002, E7012, and E7014 Emergency Discharge Unit
3
Operation and Testing
Operation
To initiate a magnet quench
1 Lift the emergency discharge button guard.
2 Press the red button.
Current will flow into the quench heater causing the
magnet to quench very quickly. Quench current will flow
for approximately 30 seconds, as indicated by the
illumination of the front panel emergency discharge
button.
To test the condition of the battery and heater circuit
1 Press the TEST button.
The BATTERY OK and HEATER OK LEDs illuminate only
if the battery capacity is okay and the quench heater
circuit is intact.
The test circuit can also be initiated by applying a TTL
input signal via the 9 ‘D’ PSU socket. A TTL output
signal is available to indicate heater integrity, making it
suitable for inclusion in digital control systems.
Option for E7012
Current can be set to flow through the B0 shield switch
heater by pressing the B0 DUMP button or via an external
TTL signal applied to the PSU or TEST connectors.
The B0 DUMP ON LED will illuminate to indicate that the
B0 shield switch heater is energized.
WA R N I N G
Following a quench, the bursting disc must be replaced and care must
be taken to ensure that the cryostat is properly sealed to prevent air
entering the helium reservoir.
C A U T I O N
When the B0 shield switch heater is quenched by these methods,
the winding remains permanently ‘dumped’ until the B0 DUMP
button is pressed or the TTL signal is removed.