TDR200-Based Time-Domain Reflectometry System
9
6.3 SDM8X50 Major Specifications
Consists of
Size
When Used
SDM8X50 50
Ohm Coaxial
Multiplexer
Multiplexer circuit
board encased in
metal housing and
a separate strain
relief bracket.
Both the circuit
board and bracket
include mounting
holes and hardware
for attaching them
to the backplate of
an enclosure
(typically the
ENCTDR100) or
to a wall.
Weight: 590 g
(1.3 lb)
Multiplexer Housing
Dimensions with
Mounts: 25 x 12 x
5 cm (10 x 5 x 2 in)
Strain Relief
Bracket
Dimensions: 20 x
4 x 1 cm (8 x 2 x
0.5 in)
When the
multiplexer
will be housed
in the same
enclosure as
the data logger
and power
supply or
when the
multiplexer
will reside in a
building
SDM8X50-E
SDM8X50
multiplexer with an
ENC10/12
environmental
enclosure.
Enclosure includes
a bracket for
mounting to a
tripod, a tower, or a
1.0 in. to 1.25 in.
IPS Schedule 40
pipe.
Weight: 4.4 kg
(9.8 lb)
Enclosure Outside
Dimensions with
Mounts: 40 x 29 x
17.5 cm (16 x 12 x
7 in)
Enclosure Inside
Dimensions:
25 x 30 x 13 cm
(10 x 12 x 5 in)
When the
multiplexer
will be housed
in its own
enclosure
without the
data logger
and power
supply
Temperature range:
–40 to 55 °C
Input power:
12 VDC
Quiescent current drain:
< 1 mA
Current drain during switching:
~90 mA (all multiplexers of the same level
switch simultaneously for less than 1 s.
See FIGURE
(p. 10)
.)
Relay contact life expectancy:
100 x 10
6
operations
7. Installation
7.1 System Components: Data Logger Control
shows the three multiplexer levels allowing up to 512 probes to
be measured. The first level includes the TDR200 and one multiplexer. Up to
eight coaxial cables connect to each multiplexer. The coaxial cables can be
connected to TDR probes or the next level multiplexers.
