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This product is no longer available and has been replaced by: SDM8X50. Some accessories, replacement parts, or services may still be available.
SDMX50SP 50 Ohm Coaxial Multiplexer with Strain-Relief Bracket
Services Available
Repair Yes
Calibration Yes
Free Support Yes

Overview

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). 

Images

Specifications

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.)

FAQs for

Number of FAQs related to SDMX50SP: 6

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  1. Why might an SDMX50-series multiplexer make clicking sounds?
    The clicking sounds come from mechanical relays making and breaking their contacts.
  2. Does an SDMX50-series multiplexer require a separate power supply?
    No. All SDMX50-series multiplexers in a TDR100 system may be connected to the same 12 V power supply.
  3. What is the difference between the SDMX50, SDMX50SP, and SDMX50LP coaxial multiplexers?

    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.

  4. Where is PC-TDR available for download?

    PC-TDR is a free download in the Downloads section of the PC-TDR web page.. 

  5. Are SDMX50-series and SDM8X50 multiplexers only usable with the TDR100 or TDR200 system?
    Yes.
  6. How far can an SDMX50-series or SDM8X50 multiplexer be separated from a TDR100 or TDR200?

    In applications where TDR probes are used to measure soil water content, the maximum distance from the TDR probe back to the TDR100/TDR200 (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).

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