VICI D-2-IM - Manual (Page 9)

5
Introduction
TEMPERATURE control and indicator
Sets the temperature (°C) of the detector heater block. The indicator is steadily on
when maximum power is being applied to the heater, steadily off when no power
is applied, and regularly blinking on/off when the set temperature has been
established.
Note that due to the fail-safe mechanism designed into the temperature controller,
the heater will not operate if mains power is applied before the heater is connected
or if the detector is too cold (< 0°C). If the heater is disconnected with mains on,
the unit must first be turned off to restore control of the heater; if the unit is
operated in a very cold environment, the detector should first be gently warmed
without power applied.
The fail-safe mechanism will also act under any condition resulting from loss of
control (e.g., over-heating, RTD failure, etc.). If proper procedures have been
followed and the controller will not heat the detector, there is cause to suspect that
the fail-safe mechanism has been activated. Consult the factory or an authorized
representative. Note that the maximum temperature for operation of the
PD-D2-IM is 400°C.
Heater control may be lost during periods of fast
electrical transients. The unit will self-recover.
MODE switch
Not used with this detector, since it is in the PDHID mode at all times.
RANGE switch
Determines the full-scale range of the electrometer: 100 nA @ 1X or 10 nA @ 10X.
CURRENT switch
Sets the standing current in PDECD mode. Not used with this detector, since it is in
the PDHID mode at all times.
ATTENUATION control
Determines the attenuation factor for the recorder output.
ZERO push button
Offsets the output signal to zero volts by a measurement of the standing current.
The offset is applied to the output when the button is released. Once set, the
offset is not changed unless the unit is re-zeroed or the mode is changed. To
remove any applied offset and restore the unit to an un-zeroed condition, toggle
the MODE or RANGE switch. The function of this control is duplicated by an
external logic connection; see UNATTENUATED OUTPUT on page 7.
Display
Indicates standing current. In the un-zeroed PDHID mode, the display indicates the
instantaneous signal current in nA. After zeroing, the display indicates the standing
current by which the signal is offset.