The SDMX50SP is one of three 50-ohm, coaxial, 8:1 multiplexers that can be used in a TDR100-based system. It consists of a surge-protected multiplexer circuit board enclosed in a metal housing and a separate strain-relief bracket. Both the multiplexer housing and strain relief bracket have holes drilled at a 1” spacing. This allows the SDMX50SP to be mounted onto a wall or attached to the backplate of a user-supplied enclosure or Campbell Scientific enclosure (e.g. ENCTDR100, ENC12/14, ENC16/18). 



Multiplexer Housing Dimensions 24.9 x 12.2 x 4.6 cm (9.8 x 4.8 x 1.8 in.) with mounts
Strain Relief Bracket Dimensions 20.3 x 4.3 x 1.3 cm (8.0 x 1.7 x 0.5 in.)
Weight 590 g (1.3 lb)

Power Requirements

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.)

Preguntas frecuentes

Número de FAQs relacionadas con SDMX50SP: 7

Expandir todoDesplegar todo

  1. The clicking sounds come from mechanical relays making and breaking their contacts.
  2. No. All SDMX50-series multiplexers in a TDR100 system may be connected to the same 12 V power supply.
  3. PC-TDR is a free download in the Downloads section of the PC-TDR web page.

  4. These three multiplexers all use the same relay board, but the housing differs. The multiplexers are described side-by-side on page 2 of this brochure.

    The most popular model is the SDMX50SP, followed by the SDMX50.

  5. In applications where TDR probes are used to measure soil water content, the maximum distance from the TDR probe back to the TDR100 (even through one or more multiplexers) cannot exceed 15 m (50 ft) when using RG58 coaxial cable; the CS605-L, CS630-L, and CS640-L TDR probes have an RG58 cable. When using low-loss coaxial cable, the distance cannot exceed ≈25 m (80 ft); the CS610-L, CS635-L, and CS645-L TDR probes have a low-loss coaxial cable.

    In slope stability and rock mass deformation applications, the maximum coaxial cable length should not exceed ≈1 mile (5,280 ft). The maximum combined length of all SDM cables in the system should not exceed ≈76 m (250 ft).

  6. Yes. PC-TDR can send control commands to advance through the channels of a SDMX50-series multiplexer. To do this, select Settings | Multiplexer and then add the multiplexers and probes that match the TDR100 system.