GE Moisture monitor series 3, Programming Manual

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Features and Capabilities 1-3
March 2008
Probes
Probes are the part of the system that come into contact with the
process flow. The
MMS-3
uses various types of probes to fit the needs
of different applications.
The term “probe” includes devices such as moisture sensors, pressure
transducers, and oxygen cells. Although users can supply their own
probes for certain measurements, GE Sensing provides the following
standard probes to make moisture, temperature, pressure, and oxygen
measurements:
•
Moisture (M) Series - moisture and temperature (in gases and
liquids)
•
Three Function (TF) Series - moisture, temperature, and pressure
(in gases and liquids)
•
Delta-F Cells - oxygen measurement (in gases).
The most commonly used probes are discussed in more detail below.
M Series and TF Moisture
Probes
The M Series and TF Series probes are very similar. Both probes use
GE aluminum oxide sensors to measure moisture, and thermistors to
measure temperature (the thermistor is optional). The TF Series,
however, has an optional built-in strain-gage-type pressure
transducer. The sensor assemblies are secured to a probe mount and
are usually protected with a sintered stainless-steel shield (TF-9
probes typically do not have a shield). Other types of shields are
available. See Figure 1-2 below and Figure 1-3 on page 1-4.
When using an M Series probe, a separate pressure transmitter is
required if in-line pressure measurement is needed. The
MMS-3
can
use any pressure transmitter with a 0/4 to 20-mA and/or a 0 to 2-V
output. Alternatively, the user can enter fixed values for temperature
and pressure into the
MMS-3
memory if the process conditions are
constant.
Figure 1-2: M Series Probe