10
World Precision Instruments
the regulating mechanism is self- venting, vacuum is automatically released when
the regulator setting is decreased. Although the vacuum gauge cannot be read
accurately at very low vacuum settings (below 2 in. Hg), reproducible settings may
still be obtained by means of the 20-turn dial regulator knob.
Vacuum–
When the
Vacuum
switch is in the
vac
position, the vacuum output port is
connected to the regulated vacuum line. When the switch is in the
atm
position, the
output port is vented to the atmosphere.
Power–
Switching the
Power
on allows the solenoid of the
Eject Pressure
line to be
activated. An amber light above the switch indicates when power is on.
Timing–
Electronic timing of the
Eject
pressure solenoid is effected by the control
section on the right hand side of the instrument front panel. Operation of the
Eject
pressure solenoid can be initiated by means of any of three different methods:
•
by manually pushing the
Start
button.
•
by applying a +5V level at the EXT Input.
•
by depressing the optional
Remote
footswitch. (The
Remote
connector is
used for accessing the footswitch only).
The length of the pulse is determined by setting the
Duration
switch. In the gated
mode the pressure solenoid opens and remains open as long as any of the three
commands is maintained. In the timed mode, an electronic timer controls the time
duration that the pressure solenoid stays open and the three commands serve only
to start the timer. Long pulses in the timed mode may be aborted by pressing the
Stop
button. A green lamp next to the
Eject
pressure gauge illuminates for as long
as the pressure solenoid is open (energized).
Period and Range–
The duration of the solenoid open time, in the timed mode, is
determined by the 10-turn
Period
dial and the setting of the
Range
switch. In the
100ms range, the solenoid times may be set from 1–101ms (every turn of the dial
is 10ms) and in the 10s range pulses may be set from 100ms to 10.1s (every turn of
the dial is 1.0s). The minimum time interval is limited by the speed of the solenoid,
which varies from approximately 10ms at 0 psi to 3ms at 100 psi.
Monitor–
The
Monitor
output connector produces a logic-level output (+5 V)
corresponding to the time interval during which the
Eject
pressure solenoid is
energized. At all other times the monitor output is low (0V).
Rear Panel
A polarized, 3-conductor, connector is used for line (mains) power input to the
instrument. A removable cordset, terminated with a grounded 3-prong connector,
is standard. An alternate cordset may be supplied when local circumstances dictate
different mains voltages and connections.
A fuseholder contains a protective fuse in series with the high side (brown or black
wire) of the mains. The holder accepts
1
/
4
by 1
1
/
4
inch (6.35mm by 31.8mm) fuses of
the type indicated on the rear panel (120V, 0.5A–#
6402
or 230V, 0.25A–#
6409
).
