METER TEROS 54 - Apparent Dielectric Permittivity; Maintenance Guidelines; Troubleshooting Guide

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TEROS 54
4.1.2 APPARENT DIELECTRIC PERMITTIVITY
Apparent dielectric permittivity ε
a
(can be used to determine VWC using external published
equations such as the Topp equation (Topp et al. 1980). Dielectric permittivity is also used for
calculating pore water EC. Dielectric permittivity is given by Equation2:
ε = –1,0898E-04 × RAW
4
+ 2,0718E-02 × RAW
3
– 1,4095E+00 × RAW
2
+4,2535E+01 × RAW + 4,7540E+02
Equation2
4.2 MAINTENANCE
TEROS 54 may be returned to METER for maintenance in the following areas: system
inspection, parts replacement, and instrument cleaning. Replacement parts can also be
ordered from METER. Contact Customer Support for more information. The nominal lifespan
for outdoor usage is 10 years, but the lifespan can be substantially extended by proper and
careful usage and by protecting the sensor against ultraviolet (UV) radiation and frost.
NOTE: Do not use any solvents for cleaning TEROS 54.
4.3 TROUBLESHOOTING
Table2 lists common problems and their solutions. If the problem is not listed or these
solutions do not solve the issue, contact Customer Support.
Table2 Troubleshooting the TEROS 54
Problem Possible Solutions
TEROS54 not responding
Check power to the prbe.
Check probe cable and stereo plug connector integrity.
Try a different port on the data logger.
Check data logger wiring to ensure the following connections:
3-wire SDI-12
Power (brown), Data (orange), Ground (bare)
4-wire SDI 12
Power (brown), Data (white), Ground (blue and black)
4-wire M12
Power (brown), Data (white), Data (black), Ground (blue)
If the probe does not respond, use the ZSC to rule out damage to
the logger.
TEROS 54 reading too low
(or slightly negative)
Check for air gaps around the probe.
Ensure the calibration equation being used is appropriate for the
media type.
There are significant differences between substrate calibrations, so
be sure to use the one specific to the substrate.