205B Series User’s Manual
3
118124-001-Rev.A
2.4.1 POLARITY REVERSAL 1kV TO 5kV
OUTPUT MODELS
The screwdriver-rotatable POLARITY SELECTOR
switch (S3) is accessible at the rear panel of the
unit. Rotate as required for the desired polarity.
2.4.2 POLARITY REVERSAL 10kV TO 50kV
OUTPUT MODELS
The polarity is reversible by means of an internal
polarity module, which is easily accessible upon
removal of the top cover. Polarity is reversed by
removing two diagonally opposed Philips head
screws, lifting up on the module, rotating it 180°,
and then reinserting it. A safety interlock
automatically ensures that the high voltage cannot
be turned on unless this module is fully seated and
installed in one polarity position or the other.
A remote polarity indication is provided at J107
(PROGRAMMING/MONITOR)
connector
jack
located on the rear panel of the unit (see section
4.3).
SECTION III: LOCAL OPERATION
CAUTION! THIS UNIT CAN STORE
HAZARDOUS VOLTAGE. COMPLETELY
DISCHARGE HIGH VOLTAGE AT REAR PANEL
GROUND TERMINAL BEFORE ATTEMPTING
REMOVAL OF THE HIGH VOLTAGE CABLE
3.1
FRONT PANEL CONTROLS
Figure 4.1 below is the typical layout of the 205B
Series front panel
Figure 3.1
SWITCHES/PUSH
BUTTONS/
INDICATORS/DIALS
FUNCTION/PURPOSE
POWER ON-OFF
Enables and disables AC power
kV/mA SWITCH
Controls the output parameter
that the front panel display
exhibits
VOLTS
Illuminated when the meter is
displaying the output current
mA
Illuminated when the meter is
displaying the output current
HIGH VOLTAGE
CONTROL
Adjusts the high voltage output
3.2
PROGRAM CONTROL SWITCH
The front panel controls of the unit are only
functional for programming purposes when the
units’ rear panel PROGRAM CONTROL switch
(S101) is in the LOCAL position. However, if the
unit receives a voltage programming command
while S101 is in the Remote Analog position, the
switching of S101 to its LOCAL position afterwards
will then cause the value of that programming
command to take effect.
3.3
LOCAL OPERATION
The local mode of the 205B Series provides all of
the control and monitoring functions available with
front panel control.
SECTION IV: REMOTE ANALOG OPERATION
CAUTION! THIS UNIT CAN STORE
HAZARDOUS VOLTAGE. COMPLETELY
DISCHARGE HIGH VOLTAGE AT REAR PANEL
GROUND TERMINAL BEFORE ATTEMPTING
REMOVAL OF THE HIGH VOLTAGE CABLE
4.1
PROGRAM CONTROL SWITCH
Before a unit can be programmed with a remote
analog (0 to +5VDC) signal, it must be configured
by setting its rear panel PROGRAM CONTROL
switch (S101) in the REMOTE ANALOG. Note:
All other monitoring and non-programming
functions remain active, regardless of the S102
position.
4.2
REMOTE CONTROL
The high voltage output can be remotely
programmed from an external voltage source. A 0
to +5VDC programming voltage applied to Pin 6 of
the J107 (PROGRAMMING/MONITOR) connector
jack on the rear panel will remotely program the
high voltage output from zero to maximum voltage.
Programming can also be accomplished using a
potentiometer connected between Pin 4 (+5VDC),
Pin 7 (GND) with the wiper connected to Pin 6.
The potentiometer should be a low temperature
coefficient wirewound or cermet type of 5k
ȍ
to
20k
ȍ
resistance value. The output will then be in
proportion to the wiper position.
4.3
ANALOG MONITORING SIGNALS
Analog monitoring signals of 0 to +5VDC via 10k
ȍ
are provided, which are linearly proportional to the
unit’s output voltage and current. A TTL-
compatible logic TRIP input, a +5VDC reference
voltage output and an NPN open collector polarity
indicator are all available at J107.
