13
SECTION 2
MECHANICAL DESCRIPTION
2.1 GENERAL
The 1061 has been
designed
to
be either rack
mounted in a standard
19"
rack
OVz"
(2U)
height re-
quired)
or bench top/portable with
integral tilt
stand. An
exploded view of
the instrument
is shown in Fig
2.1.
2.2
FRONT
PANEL
The
front
panel incorporates the signal input termin-
als, range,
function,
mode,
keyboard,
compute and power
switches
and
a numeric/legend
gas
discharge display.
2.3 REAR PANEL
The rear
panel incorporates the mains supply,
power
input
socket and fuses, digital
and analog output sockets,
rear
and ratio signal input
sockets,
rear/front
panel signal
input
selection switch,
run/calibrate keyswitch,
calibration
interval
(error) select switch
and
current
option
fuse.
2.4 EXTERNAL
CONSTRUCTION
A screen printed key designation overlay adheres
to
the front
panel retaining
the polarising filter in front of
the
display.
Both the front
and
rear
panels are held together by
two
side
extrusions running from front
to
rear. These
side
extrusions provide both
slots
for the
handles or rack
mounting
'ears' and
locating points
for the
structural
foam
covers. The
bottom cover
is
fitted with the
tilt-
stand, rubber
feet and
instruction
card. Earth
screening
of the covers and
guarding is
provided by
aluminium plates,
heat-staked to the
inside of
the covers with
electrical
connections
made by
spring contacts.
2.5
INTERNAL CONSTRUCTION
An internal chassis is
constructed from
five printed
circuit boards,
held together by
connectors
at
each corner
and
held rigid by two inner
aluminium shields fixed hori-
zontally on the instrument's centre
line
running
from
front to rear. Input
terminals, switches and display are
mounted on the front printed circuit board (pcb) and the
power supply
on
the rear pcb. The two side and centre
pcb's are used
for interconnections between
the
main
circuit boards.
All the main circuit boards are
mounted on the inner
shields with
hinges and quick release fasteners
with
flexible
connections
to allow operation in the 'hinged-up' position.
The Analog
output circuitry is fixed on
to the
rear
pcb of
the chassis and
the
Ratio/Rear
Input circuitry on
to
the
rear panel. The options
are
mechanically fitted
and require
no
soldering.
The chassis
is mounted
on to
the
side extrusions with
nylon screws, spacers
and an insulation sheet
to
ensure
that the 'electrical spacings' of
the BSI,
UL and
VDE
specifications are
achieved.
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