Campbell TDR100 Instruction Manual - page 25
TDR100
15
There are a maximum of three multiplexer levels (see FIGURE
). The
level 1 multiplexer has an address value equal to the TDR100 address plus 1.
Level 2 multiplexers have an address value equal to the TDR100 address plus 2
and the level 3 multiplexers have an address value equal to the TDR100
address plus 3.
Addressing for SDM8X50 multiplexers is set using the thumbwheel switch at
the top of the panel. For addressing details for SDMX50 series multiplexers,
(p. A-1)
7.2.6.2 SDM Cable and Cable Length Considerations
A 5-conductor cable with shield and drain is used for interconnection of SDM
devices. The 5 conductors are used for 12 volt power, ground and the three
SDM lines. A cable assembly (pn 13776) is provided with the TDR100 and
the ENCTDR100. This assembly is for SDM connection between the TDR100
and a datalogger and between the TDR100 and a SDM8X50 multiplexer. If
additional cable for SDM connection to other TDR system components is
required, the CABLE5CBL-L or the SDMCBL-L can be used. For both of
these cables, enter the cable length, in feet, after the –L. The maximum
recommended total length of all SDM cables should not exceed 500 feet.
Lengths greater than 500 feet can give unreliable communication between
SDM devices.
SDM communications use the C1, C2, and C3 ports on a CR6, CR800 series,
and CR1000. For the CR3000, use the ports labelled SDM-C1, SDM-C2, and
SDM-C3. No other devices should be connected to these ports.
The insulation for the individual wires of the SDM cable affects the frequency
response and reliability. PVC insulation has more attenuation than
polypropylene or polyurethane and should not be used for SDM
communication except when total SDM cable length is less than 250 feet.
7.2.7 ENCTDR100
Many TDR system applications require installation of equipment at field sites.
The ENCTDR100 is a weatherproof enclosure with a mounting plate for a
datalogger, power supply, TDR100, SDM8X50 or SDMX50SP, cable strain
relief bracket, and associated cabling. The ENCTDR100 can be mounted on a
CM106B tripod for free-standing installation.
7.2.7.1 Mounting Equipment in ENCTDR100
The ENCTDR100 is a 16 inch x 18 inch weathertight enclosure that is
modified for use with a Campbell Scientific TDR system (FIGURE
). The
ENCTDR100 comes with the following parts:
1. Enclosure Supply Kit; desiccant packs, humidity indicator, cable ties,
putty and mounting hardware
2. ENCTDR100 Enclosure Ground Wire Kit
3. TDR100/SDM8X50 Coaxial Interconnect Cable
4. TDR100/SDM8X50 and TDR100/Datalogger SDM 5-Conductor Cable
5. Enclosure ENC 16/18 with two 1.7 inch diameter cable penetration ports
6. Terminals for external deep cycle battery