1
TDR200-Based Time-Domain
Reflectometry System
1. Introduction
The TDR200 is the core of the Campbell Scientific time-domain reflectometry
(TDR) system, which accurately monitors soil volumetric water content, soil
bulk electrical conductivity, rock mass deformation, slope stability, or user-
specific time-domain measurements. Campbell Scientific’s TDR system
consists of the TDR200, a data logger, SDM8X50 coaxial multiplexers, TDR
probes, and
PC-TDR
software.
This manual provides information only for CRBasic data loggers.
The TDR200 is not compatible with Edlog data loggers.
2. Precautions
•
manual.
•
WARNING: Because the TDR200 is sensitive to electrostatic discharge
damage, avoid touching the inner part of the panel BNC connector or the
cent
re
rod of TDR probes connected to the TDR200.
•
The maximum recommended total length of all synchronous device for
measurement (SDM) cables should not exceed 500 feet. Longer total
lengths cause unreliable communication between SDM devices.
•
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.
•
Although the TDR200, SDM8X50 multiplexers, and TDR probes are
rugged, they should be handled as precision scientific instruments.
3. Initial Inspection
•
Upon receipt of the equipment, inspect the packaging and contents for
damage. File damage claims with the shipping company.
•
Check the contents of the shipment (see Section
(p. 2)
, Section
(p. 2)
(p. 2)
). If there is a shortage, contact Campbell
Scientific.
NOTE
